Articles containing the keyword 'soil'

Growth data were collected from 40 European aspen (Populus tremula L.) stands growing on eight localities in Sweden. The stands ranged in latitude from 56 to 66°N. The mean age of the stands was 32 years (range, 12–63), the mean stand density 1978 stems ha^-1 (range, 300–6,000), and the mean diameter at breast height (on bark) 17 cm (range, 8–34).

Site index curves were constructed for total age. Curves for H₄₀ (dominant height at 40 years total age) were made for total Sweden. Curves fitted for H₄₀ total age have another shape than curves presented by other Nordic studies. The curves from the present study have slower growth for young aspens than curves from Norwegian and Finnish conditions. For 50–70-year-old aspen stands, curves from the present study indicate taller heights than from Nordic studies.

Classified soil types from the stands were grouped into three groups: sandy till (17), light clay (15) and medium clay till (4). As there was only one stand growing in the fine sand group and one stand in the heavy clay till group and two stands in the silty till group, these stands were not presented with growth curves. There were no statistically significant differences in site index between the three soil type groups. Some recommendations for management of aspen stand are given. Damages caused by moose, fungi and other injuries are discussed as a problem for height yield production and a good timber quality.

• Johansson, E-mail: tj@mm.unknown

The effect of species mixture was studied in a mixed stand of Norway spruce (Picea abies (L.) H. Karst.) and Scots pine (Pinus sylvestris L.) by simulating around 100 different treatment schedules during the rotation in a naturally regenerated even-aged stand located on a site of medium fertility in North Karelia, Finland. Both thinning from below and thinning from above were applied. Optimum rotations were determined by maximising the net present value calculated to infinity and different treatment schedules were compared with the net present value over one rotation as per rotation applied. In the optimum treatment programme, the proportion of pines was decreased by half of the basal area in the first thinning stage and by the end of the rotation to about one third. In thinning from above, the proportion of pines can be maintained at a slightly higher level. It is economically profitable to maintain the growing stock capital at approximately the level recommended by Forest Centre Tapio, a semi-governmental forestry authority. With non-optimum species composition, the loss in net present value over one rotation can be about 10 % in thinning from below and about 20 % in thinning from above.

• Vettenranta, E-mail: jv@mm.unknown

Fresh and herb-rich upland forest sites in the north-western part of the central boreal vegetation zone in Finland were studied with respect to vegetation structure and vegetation-environment relationships (soil, stand characteristics). Two fresh heath vegetation data sets, one from the northern boreal zone and the other from the central boreal zone, were compared with the data of this study using multivariate methods.

The variation in heath forest vegetation within the climatically uniform area was mainly determined by the fertility of the soil (primarily Ca and Mg) and the stage of stand development. N, P and K content of the humus layer varied little between the vegetation classes. Fertile site types occurred, in general, on coarse-textured soils than infertile site types, may be due to the fact that the sample plots were located in various bedrock and glacial till areas, i.e. to sampling effects.

The place of the vegetational units of the study area in the Finnish forest site type system is discussed. The vegetation of the area has features in common with the northern boreal zone as well as the southern part of the central boreal vegetation zone. The results lend some support to the occurrence of a northern Myrtillus type or at least that intermediate form of fresh and herb-rich mineral soil sites commonly occur in the studied area. It is argued that the older name Dryopteris-Myrtillus type is more suitable than Geranium-Oxalis-Myrtillus type for herb-rich heath sites in the study area.

• Lehtelä, E-mail: ml@mm.unknown
• Hotanen, E-mail: jh@mm.unknown
• Sepponen, E-mail: ps@mm.unknown

Spatial variation in the density of soil organic carbon (kg/m²) and the thickness of soil horizons (F/H, E) were investigated in a 6 m x 8 m area in Scots pine (Pinus sylvestris L.) stand in Southern Finland for designing an effective sampling for the C density and studying the effect of trees on the variation. The horizon thickness of the podzolized soil were measured on a total of 126 soil cores (50 cm deep) and the C density of the organic F/H and 0–10 cm, 10–20 cm and 20–40 cm mineral soil layers was analysed.

The C density varied 3–5 fold within the layers and the coefficients of variation ranged from 22 % to 40%. Considering the gain in confidence per sample, 8–10 samples were suggested for estimating the mean C density in the F/H and 0–40 cm layers, although about 30 samples are needed for 10% confidence in the mean. The C densities and horizon thicknesses were spatially dependent within the distances of 1–8 m, the spatial dependence accounting for 43–86% of the total variance. The F/H layer was thicker and contained more C within 1–3 m radius from trees. In the 10–20 cm and 20–40 cm layers (B horizon) the C density also increased towards the trees, but more pronouncedly in the immediate vicinity of the stems. Because the spatial patterning of the E horizon thickness was similar, the increase was attributed to stemflow and precipitation of organic compounds in the podzol B horizon.

• Liski, E-mail: jl@mm.unknown

A simple, manually-operated and easily portable device for sampling volumetric soil cores to a depth of 100 cm with a minimum soil disturbance is described. The device consists of a sample tube, a sampler and an extension tube. A dead blow nylon mallet is used to force the sampler into the soil and a small winch attached to an aluminium tube pulls the sampler from the soil. The total weight of the equipment (sampler, mallet and winch) is 18.5 kg and may be carried in the trunk of a small car. Sampling is easily done by one person in good physical condition but four-handed operation is recommended as more efficient. The sampling device has been in heavy use during the summers of 1993–95 when several hundred soil cores have been extracted on various sites all over Finland.

• Westman, E-mail: cw@mm.unknown

The effects of wood ash and PK fertilization on natural regeneration and sowing of Scots pine (Pinus sylvestris L.) were studied in field experiments on nitrogen-poor (N_tot 0.87–1.26%) peat substrates. The study material was derived from three drained, nutrient-poor pine mires (64°52’ N, 25°08’ E) at Muhos, near Oulu, Finland. The experimental fields were laid out in 1985 as a split-split-plot design including the following treatments; mounding, natural regeneration and sowing and fertilization; PK (400 kg ha^-1) and wood ash (5,000 kg ha^-1). The seedlings were inventoried in circles in July–August 1991.

Changes in the vegetation were small and there were no statistical differences due to the fertilization treatments in the ground vegetation. PK or ash fertilization did not cause vegetation changes harmful to Scots pine regeneration on nitrogen-poor peatlands. Both sowing and fertilization significantly increased the number of pine seedlings, but not their height. Wood ash increased seedling number more than PK fertilizer. The number of seedlings varied from 7,963 (control) to 42,781 ha^-1 (mounding + sowing + ash). The seedling number was adequate for successful regeneration even on non-mounded, non-fertilized naturally regenerated plots.

The number of birch seedlings varied more than that of pine (370–25,927 ha-¹). Mounding especially increased the number of birches. The difference between PK fertiliser and ash was less pronounced than that for pine. In addition, to the field studies the effects of ash and PK fertilizer on the germination of Scots pine seeds was studied in a greenhouse experiment. Soaking in ash solutions strongly reduced seed germination, while the PK solution was less harmful.

• Silfverberg, E-mail: ks@mm.unknown

One-hectare plot in a Scots pine (Pinus sylvestris L.) forest was systemically sampled for surface soil characteristics: humus layer thickness, soil carbon and nitrogen content, pH, electrical conductivity and respiration were determined from 106 samples. The effects of large trees on the plot were mapped and their joint influences at the locations of soil sampling were described as the influence potential, derived from the ecological field theory, and were calculated based on the locations and dimensions of trees.

The range of variation of soil characteristics was from three to sevenfold; no spatial autocorrelation was detected. The calculated influence potential of trees, as determined by their size and spatial distribution, was related to the spatial variation of top soil properties. Top soil properties were also related to thickness of the humus layer but they were poorly correlated with underlying mineral soil characteristics. Humus layer thickness, with the calculated influence potential of trees, may provide a means to predict top soil characteristics in specific microenvironments in the forest floor.

• Hokkanen, E-mail: th@mm.unknown
• Järvinen, E-mail: ej@mm.unknown
• Kuuluvainen, E-mail: tk@mm.unknown

Forest ecosystems may accumulate large amounts of nitrogen in the biomass and in the soil organic matter. However, there is increasing concern that deposition of inorganic nitrogen compounds from the atmosphere will lead to nitrogen saturation; excess nitrogen input does not increase production. The aim of this study was to determine the long-term changes caused by nitrogen input on accumulation of nitrogen in forest soils and in ground vegetation.

The fertilization experiments used in this study were established during 1958–1962. They were situated on 36- to 63-year-old Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) stands of different levels of fertility. The experiments received nitrogen fertilization 5–7 times over a 30-year period, and the total input of nitrogen was 596–926 kg/ha.

Nitrogen input increased the amount of organic matter in the humus layer and the nitrogen concentration in the organic matter. Furthermore, the total amount of nutrients (N, P, K, Ca and Mg) bound by the humus layer increased due to the increase in the amount of organic matter. However, nitrogen input decreased the biomass of ground vegetation. The nitrogen concentration of the plant material on the nitrogen-fertilized plots was higher than on the control plots, but the amount of nutrients bound by ground vegetation decreased owing to the drastic decrease in the biomass of mosses. Ground vegetation does not have the potential to accumulate nitrogen, because vegetation is dominated by slow-growing mosses and dwarf shrubs which do not benefit from nitrogen input.

• Mäkipää, E-mail: rm@mm.unknown

Relationships between bulk density and organic matter (OM) content, textural properties and depth are described for forested mineral soils from Central and Northern Finland. Core samples were taken of 0–5, 30–35 and 60–65 cm layers at 75 plots. Three measures of bulk density were calculated: the bulk density of the < 20 mm fraction (BD₂₀), the bulk density of the < 2 mm fraction (BD₂), and laboratory bulk density (BD_l). BD_l was determined from the mass of a fixed volume of < 2 mm soil taken in the laboratory. All three measures of bulk densities were strongly correlated with organic matter content (r ≥ -0.63). Depth and gravel (2–20 mm) content (in the case of BD₂) were also important variables. BD_l was sensitive to clay contents > 7% but did significantly improve the prediction of both BD₂ and BD₂₀ in coarse soils (clay contents ≤ 7%). Predictive models were derived for coarse soils.

• Tamminen, E-mail: pt@mm.unknown
• Starr, E-mail: ms@mm.unknown

It was examined whether the present site classification method, and especially its applicability to site productivity estimation, could be improved in upland Scots pine (Pinus sylvestris L.) forests in Southern Finland by developing a classification key based on Two-way Indicator Species Analysis (TWINSPAN), and/or by inclusion of soil texture, stoniness and the humus layer depth more closely in the classification method. TWINSPAN clusters (TW) explained 71%, and forest site types (FST) 64% of the variation in site index (SI) (H₁₀₀). When soil texture (TEXT) was added to the regression model, the explanatory power increased to 82% (SI = TW + TW * TEXT) and to 80% (SI = FST + FST * TEXT), respectively. Soil texture alone explained 69% of the variation in site index. The influence of stoniness on site index was significant (P <0.05) on sorted medium sand soils and on medium and fine sand moraine soils. The thickness of the humus layer (2–6 cm) was not significantly (P=0.1) related to site index.

It is suggested that the proposed TWINSPAN classification cannot replace the present forest site type system in Scots pine stands in Southern Finland. However, the TWINSPAN key may be used to aid the identification of forest types. The observation of dominant soil texture within each forest type is recommended.

The PDF includes an abstract in Finnish.

• Nieppola, E-mail: jn@mm.unknown

The article is a literature review focusing on the reaction of soil respiration, litter decomposition and microflora of forest soils to various pollutants like acidic deposition, heavy metals and unusual high amounts of basic cations. There is a great deal of evidence indicating that environmental pollution affects soil microbial activity and community structure. Much of the data originates from experimental designs where high levels of pollutants were applied to the soil under field or laboratory conditions. Furthermore, many were short-term experiments designed to look for large effects. These experiments have an indicative value, but it has to be kept in mind that environmental pollution is a combination of many pollutants, mostly at low concentrations, acting over long periods of time. There is therefore consequently a demand for research performed in natural forest environments polluted with anthropogenic compounds. 

• Fritze, E-mail: hf@mm.unknown

In producing time series of soil properties, there are many technical and statistical problems which need to be taken into account when sampling and analysing the measurement data. In field the reliable localization of sample plots and the precise distinction of different soil layers are important to reduce the variance caused by the sampling procedure. In laboratory the use of same extraction salt, sample pretreatment procedure and filter paper throughout a measurement series is important. The remarkable small-scale variation within a sampling plot leads to a need of a large number of samples to be collected.

In this study, no trends attributable to soil acidification in the contents of exchangeable base cations could be found among the years 1982, 1985 and 1988. However, in eluvial and illuvial layers the pH decreased and the content of extractable H+ increased during this period. In illuvial layer also the content of extractable aluminium increased.

The PDF includes an abstract in Finnish.

• Ilvesniemi, E-mail: hi@mm.unknown

Five ploughed research areas from Finnish Norther Karelia were selected for comparison studies of plough ridges and untouched soil. Measurements were made at a depth of 10 cm in sample plots on both mineral and paludified mineral soil and peatland parts of these areas. In summer 1987 daily soil water matric potential was measured using tensiometers, and volumetric soil moisture content and density were determined from soil samples at two dates during the summer. Water characteristics of the core samples were also determined. On paludified mineral and peat soils the water table depth from the soil surface was measured.

The results indicated that in plough ridges matric potential was lowest. Plough ridges were also seen to dry and wet faster and to a greater degree than untouched soils. In untouched soils, soil water relations and aeration were not affected by the distance to the furrow. The effect of the plough ridge was smallest on peatland, where there was a good capillary connection from plough ridge to the ground water, if the ditches were not very effective. The soil in the ridges did not dry too much to restrict seedling growth. The untouched surface soil in poorly drained peat and paludified minear soil was, at least in a rainy growing season, often and also for long times so wet that 10% minimum air space required for good seedling root growth was not available.

The PDF includes an abstract in English.

• Mannerkoski, E-mail: hm@mm.unknown
• Möttönen, E-mail: vm@mm.unknown

The structure and functional responses of roots in planted seedlings when acclimatizing at the planting site are reviewed. A wide range of methods for classifying roots has been employed, and the terminology used is not uniform. Roots can be classified by their morphology, origin, and function. The temporal and spatial variation of soil temperature, moisture, structure, and concentration of nutrients are among the most important properties to which root systems acclimatize. In order to reliably describe the function of the root system, several parameters usually have to be measured. Studies on the root-soil interface have indicated that roots are not necessarily in continuous contact with soil. The control mechanism of root growth is inadequately known and theoretically formulated. Generally, only the mass needed for water and nutrient uptake has been allocated to the roots. However, the amount of photosynthates allocated to the roots is high. Acclimatization of seedlings out at the planting site is a complicated process which is influenced by the growing conditions at both the nursery and at the site. The function, distribution and structure of roots are controlled by the environment in a way similar to the shoot, but the control mechanism is imperfectly known.

The PDF includes an abstract in English.

• Lippu, E-mail: jl@mm.unknown
• Puttonen, E-mail: pp@mm.unknown

The winter 1986–87 was unusually cold; the snow cover remained thin and consequently the soil froze to a considerable depth. In spite of the severe frost, the lowest temperatures measured at the ground surface was -10.3°C and in the soil at the depth of 10 cm -5.8°C. The temperature sum of the following summer was unusually small and the soil frost melted more slowly than usual. The winter frosts did not have a decisive influence on the survival of planted seedlings.

The PDF includes an abstract in English.

• Kubin, E-mail: ek@mm.unknown

The effect of root exposure on the shoot and root development of Pinus sylvestris (L.) seedlings was studied at two soil temperatures. Roots of bare-rooted three-year-old seedlings were exposed to the temperature of 32°C at relative humidity of 50–40% for 85, 155 and 270 minutes which corresponds to accumulated water pressure deficit of 24, 47 and 91 mbar·h, respectively. Thereafter, seedlings were grown for 65 days at the soil temperatures of 12 and 23°C. Drought exposures inhibited new root initiation, delayed shoot elongation, and reduced shoot and needle growth. The stronger the exposure the larger the proportion of needles from the lower part of current shoot that remained undeveloped. Low soil temperature increased the effect of exposures so that needle elongation and initiation of new root tips of seedlings in cold soil with the longest exposure were inhibited totally. Root growth assessments made in warm soil may overestimate the acclimation potential of planted seedlings.

The PDF includes an abstract in English.

• Rikala, E-mail: rr@mm.unknown
• Puttonen, E-mail: pp@mm.unknown

Gravimetrically expressed nutrient concentrations of soil analysis were converted to volumetric values using dry bulk densities measured in the natural state and in the laboratory after air-drying and sieving the samples. The aim was to examine, using volumetric samples representing different soil classes, exactly how the converted nutrient values calculated by this laboratory method describe volumetric nutrient contents in undisturbed soil. In the fine soil classes undisturbed bulk density was higher than laboratory bulk density and converted nutrient concentrations were too small. In coarser soil classes the reverse was true, and the values were too high.

The PDF includes an abstract in English.

• Niska, E-mail: kn@mm.unknown

The study deals with the interaction of various soil preparation and reforestation methods. The most favourable time of the year for broadcast sowing and the effect of stabilization after soil preparation on restocking were studied as special problems.

Prescribed burning, scalping and disc ploughing made a better combination with sowing than planting, and ploughing better combination with planting than sowing. The longer the period was between sowing and germination the fewer seedlings emerged. The best stocking was clearly resulted with sowing in June. Stabilization of soil after preparation had a negative effect on reforestation results.

The PDF includes a summary in English.

• Pohtila, E-mail: ep@mm.unknown
• Pohjola, E-mail: tp@mm.unknown

Transects from upland to peatland sites were laid out so as to encounter a wide range of nutritional and hydrological conditions and volumetric soil samples were taken at 20 m intervals. For organic material, in particular peats, the correlation of ignition loss with CEC and total N were clearly higher when the variables were expressed volumetrically. The volumetric expression of variables made comparison of soils with varying organic matter contents possible. In preliminary analyses of the relationships between soil variables and dominant height of the tree stand on mineral soil sites volumetric exchangeable bases, pH and C/N -ratio in the raw humus layer showed a significant correlation.

The PDF includes a summary in Finnish.

• Westman, E-mail: cw@mm.unknown
• Laine, E-mail: jl@mm.unknown
• Starr, E-mail: ms@mm.unknown

The yield of Gyromitra esculenta (Pers.) Fr. was surveyed during 1973–82 in a Norway spruce (Picea abies (L.) H. Karst.) dominated stand in Central Finland. The soil surface was treated with different light methods, mainly removing the vegetation and humus layer.

It was shown that is possible to improve the natural yield of G. esculenta by breaking the soil surface. In the 286 m² of treated the yield could be improved over 50 fold compared to the control area. In the untreated control area, the yield per hectare was 0.98 kg/yr. In treated plots the yield was 52.4 kg/yr (in the best year 191 kg/ha/yr). Fruit bodies of G. esculenta were found in treated plots every year after the soil treatment. The yield was at its best in the two first years declining later to the level of 10–20% of the first year’s yield.

The best natural yield was reached in the last year. The previous year’s precipitation was an important factor influencing the yield of the mushroom.

The PDF includes a summary in English.

• Jalkanen, E-mail: rj@mm.unknown
• Jalkanen, E-mail: ej@mm.unknown
• Jalkanen, E-mail: jj@mm.unknown
• Jalkanen, E-mail: mj@mm.unknown

A field data set representing boreal forest-floor vegetation in Southern Finland was analysed using a simultaneous equation model. Some physical and chemical characteristics of the soil and some structural characteristics of the tree stand were treated as predictors in such a way that the tree stand factor was specified to be dependent on the soil variables. Alpha diversity, measured as the total number of species per plot, was treated as a criterion variable.

The model explains 60% of variance in the alpha diversity indicating markedly strong relationships with the site characteristics. Alpha diversity appears to increase with increases in site fertility characteristics. On the other hand, measured characteristics of the tree stand indicate no significant independent effects on the alpha diversity.

The PDF includes a summary in Finnish.

• Kuusipalo, E-mail: jk@mm.unknown

The objective of the study was to compare different reforestation methods on ploughed areas in Finnish Lapland. Four species were compared: Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst.), silver birch (Betula pendula Roth) and Siberian larch (Larix sibirica Ledeb.). The experiments were established in different parts of Lapland on different types of sites in 1970–72.

In Scots pine there was a difference of 15 percentage points in survival of seedlings between the best and worst methods of regeneration. Containerized seedlings and paper pot seedlings had the best survival rates. In Norway spruce the respective difference between sowing and planting was about 20 percentage points. In favour of planting. The survival rate can be increased by about 20 percentage points by selecting the right tree species. The average height varied from 25 cm (the sowed Norway spruce) to 179 cm (the planted silver birch) after 10 growing seasons. The birch was planted at the most fertile sites only. The longer time passed from the afforestation the clearer was the effect of the local growing conditions on the development of the seedlings. The elevation of the site was one factor seemed to influence the success of the seedlings.

The PDF includes a summary in English.

• Pohtila, E-mail: ep@mm.unknown
• Pohjola, E-mail: tp@mm.unknown

The role played by the medium and fine silt and clay contents in determining the quartiles and the degree of stratification from a cumulative particle-size curve was studied in order to determine what time savings could be made in the sedimentation phase of soil mechanical analysis. The clay content of the samples was, in general, found to be so small that it did not affect the parameters studied. In contrast to this, the medium and fine silt content affected the lower quartile of the distribution for many soils classified as finer than medium sand. Consequently, only the omission of the determination of the clay fraction can be recommended as a time-saving measure in mechanical analysis.

The PDF includes a summary in Finnish.

• Lipas, E-mail: el@mm.unknown

At immediate surroundings of a fiberglass plant in Central Sweden, vegetation shows toxicity symptoms. Soils and birch (Betula pendula Roth) leaves were sampled. The soil was analysed for water soluble and organic bound boron, carbon, nitrogen, and pH. Vegetation was analysed for total boron. Both fractions of boron in the soils increased towards the factory. Organic bound boron increased irregularly because of its strong correlation to carbon content which varied in the area. The C/N ratio increased nearer the industry due to the harmful effect of boron on the decomposition of organic matter. No relation between pH and the distance from the emission source was visible, but B/C ratio was found to increase with increasing pH of the soil. Boron levels in birch leaves were elevated very much close to the factory. The geographical distribution of high levels of boron in birch, corresponded well with high values in soils, and also with the main wind directions. The limit values for visible injury on birch were found to be around 5 ppm of water-soluble boron in soil and around 200 ppm in leaves.

• Eriksson, E-mail: je@mm.unknown
• Bergholm, E-mail: jb@mm.unknown
• Kvist, E-mail: kk@mm.unknown

A monitoring program is planned for the terrestrial environment around industries in Sweden, which emit acid compounds and heavy metals. Directions for the County Government Boards are being prepared. The paper deals with the present pollution situation in Sweden, based on recent scientific results, the justifications for local monitoring, and the organizing of the monitoring including the parameters suggested.

Four examples from a case study at an oil power station illustrate reporting of the data and the difficulties in interpreting the results. The examples are the distribution of a lichen indicator, heavy metal content and phosphatase activity in the moor layer, soil respiration and tree growth.

• Westman, E-mail: lw@mm.unknown

The areas of soil cultivation in regeneration sites using different methods in 1976–1979 and the cultivation units in use in Finland in 1979 were studied by means of a questionnaire. Application of soil cultivation methods appears to have become strongly polarized: in Southern Finland disc plowing with wheel tractors are used, whilst in Northern Finland wing plowing with crawler tractors is the most popular method, each being practically the only alternative in the respective area.

The PDF includes a summary in English.

• Kaila, E-mail: sk@mm.unknown
• Päivänen, E-mail: jp@mm.unknown

The effect of soil compaction on transpiration and height increment of Scots pine (Pinus sylvestris L.) seedlings following planting out were investigated in a small-scale pot experiment. Compacted and loosely-packed fine sand and fine-sand moraine were used as the planting substrates. The compacted soils used corresponded to the normal type of soil to be found in tilled forest soils in Finland. The effect of soil compaction on seedling transpiration during water stress was also studied in a separate experiment.

Seedlings planted in compact soil had a higher rate of transpiration than those in loosely-packed soil. The recovery in transpiration, which started halfway through the growing season, was faster, however, in the seedlings planted in loosely-packed soil. Under conditions of water stress, the seedlings planted in compact fine-sand moraine started to reduce the transpiration rate at higher soil moisture values than those planted in loosely-packed soil. No corresponding difference was observed for fine sand. Compaction was not found to affect the overall height growth, but it did at certain time during the growing season.

The PDF includes a summary in English.

• Smolander, E-mail: hs@mm.unknown
• Kostamo, E-mail: jk@mm.unknown
• Räsänen, E-mail: pr@mm.unknown

The particle size distribution affects several properties of the soil, thus, the ability to define the texture type of the soil as accurately as possible in field conditions is essential. The soil particle size classification devised by Atterberg (1912) is used in Finnish forestry. The study is based on a small laboratory material. The correlation between some characteristics of the soil particle size distribution, field capacity and cation exchange capacity were determined.

The particle size characteristics such as the relative proportion of different particle sizes, average particle size (Md) and parameters depicting the degree of sorting were determined. The relative proportion of soil particles below 0.06 mm correlated best with both field capacity and cation exchange capacity. Similarly, the average particle size and the degree of sorting correlated well with the field capacity and the cation exchange capacity.

The use of sorting characteristics is not well-suited to the type of soil sample material containing a high proportion of particles of varying size as was used in this material. Such characteristics are probably more easily applicable to the fine sand and sand sediments which are predominant in Finnish forest soils. The most useful particle size distribution characteristics in soils having a great variation in particle sizes were the average particle size and the relative proportion of silt and clay. Thus, the nutrient and water status of the soil can be predicted to some extent by examining the percentage of silt and clay, average particle size and the degree of sorting.

The PDF includes a summary in English.

• Sepponen, E-mail: ps@mm.unknown

The use and problems of the sucrose inversion method for the study of forest humus and soil are discussed. The method is based on the temperature dependence of sucrose inversion, changes in rotation angle being determined with a circle polarimeter. Average temperatures and thermal sums for forest humus in different forests in Finland were measured, using this method, for a period of ca. 100 days. The results are not considered definitive but are regarded rather as examples. Average temperatures were somewhat higher in the humus of dry and poor heath forests than in that of moist and herb-rich forests, with exceptions that could be explicable by topographic position.

The PDF includes a summary in English.

• Ohenoja, E-mail: eo@mm.unknown
• Pohjola, E-mail: lp@mm.unknown

Radial growth of Scots pine (Pinus sylvestris L.) was investigated in seven camping areas located in Southern Finland. Radial growth reduction of 20–40% were found. The magnitude of this reduction was related to the amount of damage in the trees, and the age of the trees. A loss of humus, exposure of the roots and soil compaction were associated with the use of area but not related to the reduction in growth.

The PDF includes a summary in Finnish.

• Nylund, E-mail: ln@mm.unknown
• Haapanen, E-mail: ah@mm.unknown
• Kellomäki, E-mail: sk@mm.unknown
• Nylund, E-mail: mn@mm.unknown

Gleysol profiles of five southern Finnish sites dominated by Norway spruce (Picea abies (L.) H. Karst.) were described according to the Canadian system of soil classification, and the total contents of five metals (Pb, Zn, Cu, Mn, Fe) were analysed in each soil profile. Lead, zinc and manganese showed highest concentrations in the organic surface horizons with a decrease towards mineral soil horizons. Vopper distribution was somewhat irregular. Iron had maximum values in the mineral soil: in A-horizon of Rego Gleysols and in B-horizon of Fera Gleysols. A preliminary comparison of metal pools in soil (root layer) with annual atmospheric input shows that the role of atmospheric deposition is relatively greater in the case of Cu, Zn and Pb than for Fe or Mn.

The PDF includes a summary in English.

• Vasander, E-mail: hv@mm.unknown
• Mäkinen, E-mail: am@mm.unknown
• Pakarinen, E-mail: pp@mm.unknown

The paper deals with the nutrient status of surface peat layer from virgin sedge-pine swamps and its relationship to peatland types. When the nutrients are expressed in mg/100 g peat, only easily extractable Ca and Mg correspond to the productivity status of the peatland type. N, P, and K levels in the herb rich sedge-pine swamp are generally lower than in the small sedge-pine swamps, which are the least productive ones. The differences between the site types in all the five nutrients become much clearer when the results are expressed in kg/ha. P, K, and Ca are significantly different between the site types, and correspond to the productivity of the site type. For N and Mg the same tendency can be seen. The organically bound nutrients N, and to a lesser extent, P appear to comply with the hypothesis of an increase in nutrient availability in Southern Finland.

The PDF includes a summary in Finnish.

• Starr, E-mail: ms@mm.unknown
• Westman, E-mail: cw@mm.unknown

The paper deals with variation in the nitrogen, phosphorus, potassium, calcium and magnesium content of vegetation and soil of young Scots pine (Pinus sylvestris L.) stand of Vaccinium site type situated in Central Finland. The material consists of sequential samples representing soil, ground vegetation and trees taken during summer 1974.

The amount of soluble nutrients in the humus layer decreased in June when maximum growth of trees and dwarf shrubs occurred. The nutrient content of this layer subsequently began to increase towards the end of the growing period.

The variation in the nutrient content of the bottom and ground layers followed a similar pattern. Nitrogen content increases at the beginning of the summer. After this phase it started to decrease and reached its lowest values by the end of growing period. Phosphorus and potassium content increased throughout the growing period.

The nutrient content of the needles and wood were positively correlated with tree height and negatively with the age of material. The highest values for the nutrient content were for new cells.

The PDF includes a summary in English.

• Lehtonen, E-mail: il@mm.unknown
• Kellomäki, E-mail: sk@mm.unknown
• Westman, E-mail: cw@mm.unknown

During the next decade there will be a marked increase in the allowable cut in drained peatlands. At the same time, the mechanization in logging proceeds, and in short-distance haulage the use of forwarders will increase. This study, based on literature and some observations, deals with logging conditions in drained peatlands with special reference to the suitability of heavy logging machines for use in such terrain. In addition, soil frost and the bearing capacity of the frozen peat soil were studied.

Freezing of the soil in a drained peatland area depends prevailingly on the weather conditions during early winter. The factors influencing soil freezing of a drained peatland are completely different from those regulating the freezing of natural peat soils. The frost penetrates in general deeper in the drained than virgin peatland. The topmost peat layer does not, however, freeze uniformly. Generally speaking, the bearing capacity of a drained peat soil is lower than that of undrained peat due to lower water content.

It is concluded that heavy logging machines are probably not fitted for use in drained areas on peatland even if the average soil frost values recorded would suggest it. Moreover, because of their extremely superficial root systems, peatland forests are exposed to damages by heavy machines in thinning operations.

The PDF includes a summary in English.

• Hannelius, E-mail: sh@mm.unknown

The paper describes the results obtained from an investigation into the effect of thinning of different intensity and fertilization on the depth and water equivalent of the snow cover as well as on the depth of the soil frost in a young Scots pine (Pinus sylvestris L.) stand growing on drained peatland in Central Finland. Thinnings and fertilization was carried out in 1968, and the snow cover was followed in the winters 1970/71 and 1971/72.

Only extremely heavy thinnings (60% of the volume) seemed to increase the depth and water equivalent of the snow cover. The indirect effect of fertilization on the snow cover was insignificant. In the clear-cut sample plot of the study, soil frost was either not found at all or the depths of the frozen soil layer was smaller than in the other plots. When deciding the silvicultural measures to be taken in the case of tree stands growing on drained peatlands, there seems to be reason to avoid radical thinnings. Otherwise, the favourable influence of the trees on a site on its water relationships will be diminished.

The PDF includes a summary in English.

• Päivänen, E-mail: jp@mm.unknown

Under the soil bank act, which took effect in 1969, 85,000 hectares of agricultural land were withdrawn from agricultural production in order to cut down the heavy surpluses of grain and butter in Finland. The farmers have a possibility to afforest their soil bank land partly on public funds, and if they choose to do so they receive a compensation of 250 Fmk for 15 years, instead of the nine years which is the maximum duration of a soil bank contract.

The study involved interviewing of 136 farmers sampled from the total of 13,368. The farmers were planning to afforest a total of 18,600 ha by the end of 1972. The main species were birch (Betula sp.) 40%, Norway spruce (Picea abies (L.) H. Karst.) and Scots pine (Pinus sylvestris L.) both 30%. The main reasons (mentioned by 65% of the farmers) for afforestating the soil bank land were the unfavourable conditions for agriculture. On the other hand, 43% of those who had decided not to afforest felt that their land is too good to be planted with trees. One fifth of those not afforesting said that they themselves would not benefit from the afforestation and therefore were not interested in investing in forestry. The attitudes of the farmers seem to have also influenced their decision on afforestation. Those who had taken a positive decision on afforestation appeared to take more positive attitude in regard to forestry than other farmers.

The soil bank act does not seem to solve permanently Finland’s problem of the surpluses of agricultural products since the soil bank farmers planned to revert two thirds of the soil bank land under cultivation on the expiration of the soil bank act.

The PDF includes a summary in English.

• Numminen, E-mail: jn@mm.unknown

The purpose of this study was to explain whether it is possible to affect, in practical working site conditions, by means of logging waste on the strip road, the depth of the track which is formed in terrain transportation and the injuries of the growing stand. Five 20 m long investigation areas with logging waste and five similar areas without logging waste were arranged on one strip road at Teisko logging site in Southern Finland. The logging waste layer was mainly Norway spruce and 10–15 cm thick. A KL–836 B forwarder was used. The type of soil was loam.

The logging waste affected the depth of the track only by decreasing the wear of humus layer. Even decreasing effect of logging waste on the injuries in the growing stand was minor. At Kitee working site in Eastern Finland strip roads were studied. The type of soil was thick, rather mouldered peat. The thickness of logging waste was 3–4 times greater than in Teisko, mainly spruce. A Volvo Nalle SM 460 forwarder was used. The effect of the logging waste on the depth of the tracks was clearly to be noticed. On basis of the appearance of the tracks one could assume that the difference was due to different wear of the humus, and not so much due to the quantity of logging waste that improves the carrying capacity of terrain.

In some extent logging waste was also found to affect the amount and quality of tree injuries. In practical working conditions, the importance might be small, since in the experiments an unrealistically great amount of logging waste was used.

The PDF includes a summary in English.

• Kärkkäinen, E-mail: mk@mm.unknown

The aim of this paper was that of studying the optimum growing schedules of forest stands, with the classic Faustmann formula as starting point. The study is mainly theoretical in nature. The study shows that the net present-value of the future revenues from a forest stand can be calculated, not only by means of the harvesting revenues, but also by a more theoretical concept, here termed the current gross soil rent. The current gross soil rent represents the difference between the current value growth and the rent of the growing stock.

By use of the concepts described here, it is theoretically possible to find the growing schedule for the stand which maximizes the net present-value of the stand. To make the formulae simpler, a one-year period has been adopted for discussion of the concepts involved in determination of the optimum structure and density of the growing stock, and the financial maturity. However, these concepts can be extended to cover periods of any length.

The method for determination of the optimum growing schedule for a forest stand can be summarized as follows: Thin the stand as the internal rate of return on the marginal increase in ’timber capital’ falls below the guiding rate of interest. Clear-cut and regenerate the stand as the internal rate of return on the sum of the ’timber and soil capital’ falls below the guiding rate of interest.

The PDF includes a summary in Finnish.

• Kilkki, E-mail: pk@mm.unknown

The technical term reduced yield stands – sometimes reduced yield soils – is widely used in the Finnish forest literature. However, there is no clear definition of the notion reduced yield and no explanation of how this notion is measured in the classifications. Some committee reports and bill proposals and some laws and statutes use the reduced yield forest soil. No definition can be found. In my opinion the term reduced yield forest soils ought to be completely abolished until forest soil experts can perhaps define what it means, if they consider such a concept useful.

Explanations for the term reduced yield stands can be found in the descriptions of classification systems of stands. According to them, the criterion is partly silvicultural (site, species of tree), partly mensurational (volume, sometimes growth), partly economic. No explanation is found as to how the economic aspect is measured, nor about the limit of a full yield and reduced yield.

In my opinion such a term is confusing. I therefore suggest that the term reduced yield stand ought to be abolished. If something is needed instead, I suggest the term understocked stand, defined as a growing stock under certain percentage of a fully stocked stand. The notion of economic reduced yield cannot be generally tied to certain silvicultural and mensurational characteristics of stands. The economic aspect of certain kinds of stands may differ, depending on the owner of the forest and his economic situation, the location of the forest, the composition of the whole forest ownership unit, etc.

The PDF includes a summary in English.

• Saari, E-mail: es@mm.unknown

During the summer and fall of 1966 changes brought about by urea, calcium ammonium nitrate, nitrate of lime, and ammonium sulphate were observed. Application of the fertilizers corresponded to 100 kg/N per hectare.

The effect of urea was immediate. The pH rose and the bacterial density increased to 20–30 times more than determined in the spring, while the microfungal density decreased to one third of the spring density. In the ammonium sulphate plot opposite changes occurred almost as rapidly as in the previous case. A gradually increasing biological activity observed after application of calcium ammonium nitrate and of lime fertilizers seemed almost the same for bacteria and microfungi. Both microbe groups displayed consistent quantitative growth. pH 4.3 was the limit of acidity below which the bacteria showed a tendency to decline and the microfungi to increase, while the opposite was true above this limit.

The PDF includes a summary in Finnish.

• Schalin, E-mail: is@mm.unknown

This study elucidates the composition of the microfungal populations of the humus layer of tree forest types – Vaccinium type with Scots pine (Pinus sylvestris L.), Myrtillus type with Norway spruce (Picea abies (L.) H. Karst.) and Oxalis-Myrtillus type with birch (Betula sp.). The results indicate that the microfungi encountered in these sites bear close resemblances. The number of species increased but little towards the more fertile sites from VT to OMT. The main difference was limited to the quantitative relationships between the species.

The microfungal density in the humus layer was greatest in VT, and only slightly less in MT and OMT, in this order. In all the sampling areas, occurrence of the microfungi reached a maximum in the middle of summer, at a time when the maximum temperatures were registered in the humus. The quantitative abundance during the early autumn bears a relation to the yield of litter.

The microfungi most commonly encountered in all sampling areas were those of rapid growth, Mucor, Morierella and Penicillium species, along with Trichoderma, a little slower in growth, and actively decomposing cellulose. Mucor fungi, favouring moisture, were most abundant in the early summer and in the autumn. The Mortierella and Penicillium species, which survive dryness, were most abundant in the middle of the summer. The former is twice as common in MT and OMT than in VT, and the latter twice as common in VT as in OMT.

Scopulariopsis and Verticillium species were found regularly in MT and OMT. One Acremonium species was found almost exclusively in VT, and some Aspergillus and Mycogene in OMT alone. Sterilia mycelia was relatively abundant in MT and OMT in particular. Different kinds of yeast fungi were encountered generally in MT and OMT.

The PDF includes a summary in Finnish.

• Schalin, E-mail: is@mm.unknown

This study estimates the supply of soil water required for the annual and total production of energy material by the biomass of 32-year-old plantation of red pine, Pinus resinosa Ait. in Wisconsin, the United States.

The supply of transpiration water was determined as the sum of summer precipitation, winter stored water, and condensed vapor, minus gravitational discharge and evaporation of intercepted rainfall. On the average, the 1,20 m root zone of coarse sandy soils of central Wisconsin receives 2,750 M.T. of water per hectare. During the 32nd year of plantation growth, the increment biomass, including 43% of merchantable timber, was 10,100 kg/ha, or 162 x 105 kcal/g. At this time of the culminating growth, the production of 1 kg of wood material consumed 272 kg of water. The corresponding transpiration coefficient 0,37% is near the maximum for the ecosystem of hard pines – sandy soils of glacial outwash with field capacity between 7 and 9%. On the weight basis, the annual leaf fall constituted 32% of the biomass and over 80% of merchantable timber.

The entire supply of water of 96,000 M.T./ha produces in 32 years 211,112 kg of total dry matter at a rate of 1 kg of wood per 455 kg of water, with corresponding transpiration coefficient of 0,22%. The evapogravitational losses during the early stages of the stand’s growth decreased the water utilization efficiency of trees about 40%.

The information obtained permitted to outline several hydrological relationships pertinent to forest culture, namely: maximum rate of forest growth as delineated by the supply of available transpiration water; content of available moisture in soils of high tension capacity; contribution to soil water rendered by natural subirrigation and condensation of athmospehric vapor; growth depressing effect of weeds.

The PDF includes a summary in Finnish.

• Wilde, E-mail: sw@mm.unknown

No other manifestation of life is allied more conspicuously to the theory of relativity as the growth of forest stands which is a function of the inherent growth potential of trees, the productive capacity of environment, and time.

The height over age quotient of a forest stand is usually the most reliable indicator of the productive forces of the habitat. Stem analysis have shown that increment of a tree at different ages is closely correlated with the extension of roots into individual geological horizons of different productive capacity. Growth curves of stands of a same tree species growing on different soils can be disparate due to different conditions. The temporal variety of tree growth on different sites is of prime importance in the construction of yield tables. Investigations of natural plant communities of Finland provided one rational approach towards the construction of yield tables. By confining mensuration analyses to define floristic types, the Finnish foresters harmonized their records with Einstein’s formula for space-time matrix of material events.

• Wilde, E-mail: sw@mm.unknown

The aim of the study was to find out more about pine weevil (Hylobious abietis L.) injuries in Scots pine (Pinus sylvestris L.) seedling stands and their control by means of DDT. For this purpose, inventories were made of seedling stands established earlier. Control experiments were made on burnt areas by planting seedlings dipped in a DDT emulsion.

The results of the inventories show that injuries caused by pine weevils can, in certain circumstances, especially in seedling stands established by planting, cause the complete failure in artificial regeneration. The extent and quality of the injuries vary greatly according to planting method, treatment of the cutting area, age of the seedling stand, environmental factors, and weather conditions. The most extensive injuries occur in regeneration areas of old Norway spruce stands burnt after clear cutting and planted with Scots pine seedlings. Injuries are greater in seedling stands established by planting, especially after broadcast burning, than in seedling stands originating either from artificial or natural seeding. The quality of the patch for sowing or planting has a considerable effect on the quantity and character of the injuries: in a patch from which organic matter has been removed, injuries do not appear or they are slighter. Seedlings can be protected effectively and economically by dipping their tops up to the root collar, in a DDT emulsion before planting.

The PDF includes a summary in English.

• Nenonen, E-mail: mn@mm.unknown
• Jukola, E-mail: jj@mm.unknown

The article is a summary of a presentation by W. Wittich, held in the University of Helsinki in 26.4.1958.
The significance of fertility of the site in tree growh was known already for over 100 years ago in Germany, but after the First World War the view was abandoned in forestry. According to the Dauerwald system of managing forests that was introduced at the time, the type of site was considered relatively insignificant in forest management. Therefore, similar practices were used in all kinds of sites. The opposition against the use of this method resulted in new research on the site factors.
Knowledge of the relation of the site types and vegetation makes it possible to improve productivity: in regional planning the production that is considered to be necessary is assigned to the sites that have best conditions for it. For instance, in Niedersachsen county about 6% of the forest lands are reserved for cultivation of oak.
Another line of soil science studies the root causes behind the hands-on experiences of forest management. The aim is to abandon rigid approaches in forestry. Studying the effects of forest management practices on soil has been targeted, for instance, on effects of clear cutting on decomposition and vegetation, how the soil affects choice of tree species, and decomposition of litter from different tree species. Knowledge of soil and the trees’s demand of nutrients helps to mend disturbancies, such as nutrient deficiensies. Consequently, fertilization has become a new tool to improve productivity in forestry.
The article includes a German summary.

• Wittich, E-mail: ww@mm.unknown

Silva Fennica Issue 80 includes presentations held in 1952 in the 7th professional development courses, arranged for foresters working in the Forest Service. The presentations focus on practical issues in forest management and administration, especially in regional level. The education was arranged by Forest Service.

Soil preparation improves formation of seedlings in natural regeneration sites. This presentation describes mechanization of the work using four different machines. According to the study, the effectiveness and quality of the work has improved compared to the earlier machines, and the method is becoming a competitive alternative to slash burning.

• Hautamäki, E-mail: th@mm.unknown

Silva Fennica issue 46 includes presentations held in professional development courses, arranged for foresters working in public administration in 1937. The presentations focus on practical issues in forest management and administration, especially in regional level. The education was arranged by Forest Service. 

This presentation describes the effect of properties of soil on forest regeneration. 

• Aaltonen, E-mail: va@mm.unknown

Dilution plate method was used in studying the density and composition of the microfungal populations of the organic layer of Scots pine forests, and the soil-plate method in studying the part of these populations decomposing cellulose. The media used were rose bengal agar (Martin’s medium for fungi) and cellulose medium.

The microfungal density depended to a considerable extent on the moisture content and temperature of the organic layer. Only the combination of relatively high moisture content and temperature, but neither of these factors alone, influenced considerably the microfungal population density. The correlation of the populations to the changes in this combined factor was stronger than the correlation to the seasonal variations of spring, summer and autumn.

The microfungal population consisted of only a few species. Mucor, Mortierella and Penicillium were the most common genera isolated from the rose bengal agar. The first and the last of these comprised almost 90% of the total population. For the Mucor fungi, increases in the moisture content up to the maximum values found (75%) were favourable; the Penicillium fungi, on the contrary, were intolerant of high moisture content.

Among the cellulose decomposing microfungi grown on cellulose medium, Trichoderma sp. was the most common; also, it formed the most colonies, tolerated the lowest temperatures, and was most efficient. The others were of the genera Pullularia, Verticillium, Scopulariopsis and Penicillium. In addition, there were some unidentified Phycomycetes fungi. Only the two first-mentioned caused observable changes in cellulose.

• Schalin, E-mail: is@mm.unknown

Quantitative investigation of bacteria in the humus is needed when the intensity of their function in decomposition in the soil is studied. In this study bacterial density of humus was measured using dilution plate method, which was subjected to thorough investigation. The method was chosen, despite its complexity, because it is quite consistent, each stage can be studied separately and the reliability can be tested. The aim of the study was to determine the best way to take samples so that the sample will represent the bacterial population as closely as possible, and to optimize homogenization and dilution of the sample and the assays.

On the basis of the results of the investigation, a procedure was developed for quantitative determination of aerobic bacteria in the humus by the dilution plate method. The paper recommends that subsamples are collected systematically from at least 25 different points. The moisture and temperature of the samples should remain similar to the natural environment until preparation of the dilution. The sample was homogenized with the Bühler homogenizer, which is constructed so that a certain degree of asepsis can be maintained and the speed of the apparatus can be regulated. The content of the mineral nutrients of the sample must be determined when choosing the way of homogenization to obtain the highest number of colonies per plate. The sample was diluted with either 0.1–0.01% peptone solution or 0.5% soil extract. The most advantageous degree of dilution was obtained by testing with the aid of Fisher’s dispersion index the probability of the Poisson distribution in the results.

• Schalin, E-mail: is@mm.unknown

The investigation is divided into statistical and experimental sections, the latter of which were conducted in a Vaccinium type Scots pine (Pinus sylvestris L.) stand with the aim of elucidating the interdependence of soil humidity and meteorological factors. The moisture content of pine needles and moss and wooden cylinders placed on the soil or slightly over the ground was determined by weighing. The results showed that there is correlation between the moisture content of the wooden cylinders and the relative humidity of air during the days without rain. Correlation between moisture content of pine needles and moss with the air was slightly poorer.

In the statistical section, based on meteorological observations made in the geophysical observatory at Sodankylä in Northern Finland in 1920-1943, and forest fire statistics of the area, forest fire days and days without forest fires were divided into 40 temperature-humidity groups. Of the 391 forest fires observed in the area, the cause of the fire was known in 353 cases, and 69% of these were caused by lightning. A forest fire danger index was calculated using the data. A sharp increase in the burned area when the index exceeded the limit k=0.3 seem to be explained by thunderstorms, which are the most notable cause of forest fires in the Sodankylä area.

The forest fire index was calculated also at four meteorological stations in different parts of the country using weather observations in 1927-1936. It appears that the number of days in which the k>0.1 decreases when proceeding northwards, obviously because of the shortening of the summer. On the other hand, the number of days in which k>0.3 increases towards the north.

The PDF includes a summary in English.

• Franssila, E-mail: mf@mm.unknown

Litters of different plant species vary greatly in regard to their nutrient content and other properties. The aim of the study was to compare different litters from the standpoint of their value as soil fertilizer. In an experiment Scots pine (Pinus sylvestris L.) seedlings were grown in pot cultures in which known amounts of different litters had been mixed with the soil. The tested litters were Pinus sylvestris (L.), Larix sibirica (Ledeb.), Betula sp., Populus tremula (L.), Alnus incana (L.) Moench, A. glutinosa (L.) (Gaertn.), Sorbus aucuparia (L.), Tilia cordata (Mill.), Acer platanoides (L.), Corylus avellana (L.), Eupteris aquilina (L.), and Deschampsia flexuosa (L.) Trin.

A striking difference was found between alder (Alnus sp.) leaf litter and all the other litters tested. The difference can be seen from the second growth season on, becaus the young seedling uses mainly the nutrients included in the seed. The leaf litter has mainly unfavourable effect on the growth of the pine seedlings. Only both alder species improve the growth. This is mainly due to the nitrogen content of alder leaves. Tree leaves and other forest litter are often composted in the forest nurseries. It seems that adding nitrogen to the compost is necessary, otherwise compost added to the soil may have a harmful effect on the seedlings. Alder, on the other hand, has nitrogen binding Actinomyces growing in symbiosis in its root nodules, and is able to utilize atmospheric nitrogen.

The PDF includes a summary in Finnish.

• Mikola, E-mail: pm@mm.unknown

Germlings and small tree seedlings are exposed to extreme conditions in the forest floor. In this study the influence of climatic factors to seeds and seedlings were studied experimentally, and an attempt was made to estimate the importance of various factors in several sowing experiments in Finland.  

Seeds of Scots pine (Pinus sylvestris L.) were subjected to temperature variations which simulated those of exposed forest sites. The seeds lost some of their germinative capacity during the five-day treatments. Succulent seedlings died when subjected to immersion for 15 minutes at temperatures from 51.5 to 55 ºC. After a hardening pretreatments the seedlings tolerated 2-3 ºC higher temperatures. In artificial humus soil exposed to strong insolation for 15 minutes, temperatures in the range of 54-65 ºC proved to be critical for the seedlings. In natural conditions, also little lower temperatures may prove fatal. Exposure of succulent seedlings of Scots pine and Norway spruce (Picea abies (L.) Karst.) to insolation showed that most damage occurred on humus, quartz sand, and humus-sand mixture, due to rapid evaporation. Seeds of Scots pine, Norway spruce, Betula pendula and Betula pubescens tolerated poorly drought if germination had progressed to a 5–10 mm long radicle. Succulent seedlings tolerated 53-77 days long drought better in humus than in fine silty sand. Seedlings of Pinus sylvestris, Picea abies, Alnus incana and A. glutinosa tolerated cold variably. The developmental stage of the seedling affected cold resistance. Pine seeds sown in furrows germinated well after rain and the survival was high. Frost heaving, snail and insects caused some damages. Germination was lowest at the shallowest furrows. Sowing on natural surfaces gave poor results. Largest damages were caused by birds and ants. 

 The PDF includes a summary in Finnish.  

• Vaartaja, E-mail: ov@mm.unknown

The purpose of this investigation was to obtain a preliminary picture of the composition of the microbial population in some virgin soils on forest land in Finland. Four different forest types were studied, Oxalis-Myrtillus type birch (Betula sp.) stand, Oxalis-Myrtillus type Norway spruce (Picea abies (L.) Karst.) stand, Vaccinium type Scots pine (Pinus sylvestris L.) stand, and drained pine bog. In addition, a flood meadow was selected as a comparison.

The methods used captured only part of the fungi growing in the soil. Rapidly growing types, especially Mucor and Penicillium species, were mainly isolated. In addition, fungi showing activity of decomposition, such as Fusarium, Monosporium and Spicaria, as well as an ascomycete of the genius Ascobolus, were isolated. Autochthonous bacteria were most abundant in the soils of Oxalis-Myrtillus type forests and in the flood meadow. In the birch stand 90% of the autochthonous bacterial flora were gram-negative bacteria, in the Oxallis-Myrtillus spruce and Vaccinium type pine stand 60% were gram-negative, while the share was only 25% in the pine bog. Nitrogen-fixing bacteria of the type Clostridium pasteurianum were found in all soils. Actinomycetes were found in all sites. The numbers of protozoa were highest in the soils of Oxalis-Myrtillus type forests.

There were no big differences between the forest soils and the flood meadow. Some groups of micro-organisms seem to be absent from the forest soils, which is probably due to the more favourable pH in the meadow. The occurrence of myxobacteria is interesting since no earlier data exist of this organism in Finnish soils.

The PDF includes a summary in English.

• Gyllenberg, E-mail: hg@mm.unknown
• Hanioja, E-mail: ph@mm.unknown
• Vartiovaara, E-mail: uv@mm.unknown

Soil frost from the winter 1941-1942 was of a special form. To create such a strong soil frost there need to be capillary soil form and long period of permanent and intense cold, meaning minus temperatures.  The frost layer was thicker than normally.

Such a frost causes many problems on the fields and roads when the soil rises because of the frost and then falls unevenly back when the frost melts.

• Kokkonen, E-mail: pk@mm.unknown

Earlier studies show that different kind of biological processes occur in the soil of different forest types. These differences may be due differences in microbiology of those soils. This article studies these differences.

Soil samples from five different forest types were collected from the Ruotsinkylä research forest in three different seasons: in January, March and September.

The amount of bacteria in the samples is at the lowest in March and highest in September.   During the winter more anaerobic bacteria were found. The amount of denitrifying bacteria is higher in the soil than amount of nitrifying bacteria.

The results indicate that the species composition of soil varies between the forest types in the same manner than the vegetation composition above the soil. However, this study is only a preliminary and more knowledge is needed about the discipline before practical implications can be drawn.

The PDF contains a summary in Finnish.  

• Svinhufvud, E-mail: vs@mm.unknown

The article presents the studies about the vegetation communes on moisture soils in northern Finland. The studies are part of another study about calcium carbonate content of the soil as a factor influencing the vegetation.

The PDF contains a summary in Finnish.  

• Pesola, E-mail: vp@mm.unknown

After critically reviewing earlier studies on soil properties and their influence on forest growth and yield, it seems that defining the forest yield could be possible by means of soil properties. To be able to do so, the site needs to be defined and delineated in some other way. It is also necessary to decide the right soil properties to study for the purpose.

For the classification of forest sites the results of soil analyses need to be compared with growth and yield data from the site. To further the practice of classification of forest sites by means of soil studies, four aspects need to be taken into account:

1)  the site needs to be delineated beforehand according its vegetation, preferable with Cajander’s forest type classification

2) the experiments about soil needs to be done for as many properties as possible

3) the studied sites need to be as representative as possible in their class

4) there are as many samples for one site as possible studied

The volume 34 of Acta Forestalia Fennica is a jubileum publication of professor Aimo Kaarlo Cajander.

• Aaltonen, E-mail: va@mm.unknown

The article presents three studies about different aspects of the bio-chemical functions of forest soil. The three studies are i) research on microflora and microfauna of forest soils; ii) study on carbon nutrition of forests in relation to microbial functions of soil and effecting site factors and iii) study on nitrogen metabolism of forest soil. The results of the studies are summarized by every study.

The article discusses the meaning of the results for forest management in practice. The good biological and physiological condition of forest soil is important for the forest growth and it needs to be taken care in regeneration and other forest management. The natural regeneration seems to be better for soil functions. Favoring broadleaved trees as undergrowth enhances the biological processes of forest soil.   

The volume 34 of Acta Forestalia Fennica is a jubileum publication of professor Aimo Kaarlo Cajander.

• Fehér, E-mail: df@mm.unknown

The article presents some basic elements of soil frost and its occurrence.  The data contains observations from different regions and soil types in Finland. Different forms of soil frost and factors affecting its formulation are discussed. 

• Kokkonen, E-mail: pk@mm.unknown

The study is based on the results of the soil studies by Valmari (1921) and the growth inventories of respective areas. The aim is to show the connection of soil fertility (nutrient content) and forest growth with means of correlation calculations. The examined nutrients were nitrogen, calcium and phosphorus, also the electrolyte content was studied.

• Ilvessalo, E-mail: yi@mm.unknown

The article deals with laboratory experiments of humus containing soil samples that were tested for leaching of iron and lime. The humus and soil samples were collected in five different areas in Silesian state forests, Germany.

The chemical content of the extracts was measured in the beginning of the test. The flocculation experiments and experiments in glass tubes took place. The stronger or weaker the podsolization, the greater or smaller was the protective action of hums at the respective place. However, more research is needed. The results of the glass tube experiments seem to indicate that with humus there were smaller amounts of Ca and Fe leaching than with merely water. 

• Aaltonen, E-mail: va@mm.unknown

This is a working paper. It presents the laboratory experiments with soil samples from northern Finland, in which the precipitation of iron (Fe) was tested with limewater (Ca). There was no clear difference between samples with limewater and samples without limewater. However, the lime prevented the infiltration of iron almost totally.

The mineral content of soil effects the forest growth and yield and hence it is of interest for forestry. More research is needed both as field experiments and in the laboratory. 

• Aaltonen, E-mail: va@mm.unknown

The article contains a literature review about the spatial order of plants and a description of the small-scale experiments with corn. The literature is primarily of German origin. The question of the spatial conditions of trees in forest is important for practice of silviculture. The first part of the article illustrates based on the literature the importance of roots and root concurrence for the development of plants or forest stands. The second and third part deepens the methodological knowledge on root research. Fourth part is the field experiments with corn. There are no clear relation to be found between yield and the number of plants.  

• Aaltonen, E-mail: va@mm.unknown

The article is a presentation given by the author on occasion of visit from Austrian timber industry and foresters (August 17^th 1923) in Punkaharju, Finland.

The article presents the classification of soils as forest types to describe their fertility and their occurrence in different parts of Finland. The economic conditions are only shortly mentioned: the more fertile areas in southern and western Finland have been taken for agriculture and the less fertile soils have stayed forested.   

• Cajander, E-mail: ac@mm.unknown

The paper studies the relationship of settlements to the forest types and forest soil. The observations have been done and data collected in southern Finland, around lakes Päijänne and Saimaa during summer 1917. Because of the shortcomings in the data, the results in the paper can be seen only as indicative.

The settlements have spread out firstly to areas of grove alike soils and herb-rich forests. The human settlements are still on these days concentrated on those areas. When more land is needed for agricultural purposes, the more fertile areas were introduced first. With forest type classification this means moving from herb-rich Oxalis-Myrtillus-type to Pyrola-type and to some extent Myrtillus-type. The more barren types are used as fields only very seldom. The differences in the fertility of the soils affects strongly the welfare and development of the people and the communes. 

The study shows that when considering the soil and vegetation, preconditions for agriculture are very different in different part of Finland. Also the climate and the geographical characters vary. To win more agricultural land, the fertile peatlands should be considered.  

• Linkola, E-mail: kl@mm.unknown

The article is based on the work “Metsänhoidon perusteet I” [The fundamentals of Forest management I] by the author (1919 in Finnish). The different processes of the soil and the vegetation are dependent on the climatic conditions, but also affect each other. The article presents the climatic zones of the earth and their most important characteristics in regard of cultivation of (to respective zone) exotic trees species and agriculture. 

• Cajander, E-mail: ac@mm.unknown

The article tries to develop the method for defining the requirements of fertilizers for soil. The chemical soil analysis is also seen as the requirement for exact site classification based on height over age. The study is based on 1500 soil samples, one half of them from forest soils, the other half from arable land soils.    

The productivity of different forest types and the results of soil analyses are in line with each other. The most important growth factors are discerned.  Some shortcomings of the method are discussed.  Combining the soil analysis and the plant analyses of the sample plots seems to give the most accurate about the amount of nutrients that are available for the plants.

• Valmari, E-mail: jv@mm.unknown

The data has been collected in the dry heathy forests in Harjavalta commune in south-west Finland and in Sodankylä commune in Lapland in summer time 1918 and 1919. The aim to the study was to find out how does the water consumption of the trees affect the moisture conditions of the soil and how they are linked to the regeneration of the forest.

Trees in one age class have a certain spatial distribution: the greater the distance between trees the older the trees and the smaller the distance, the younger the trees. This seem to rather be due to the development of the root system and the nutrition intake of a tree than the competition for light. The moisture content of the upper soil layers is higher in the open areas than in the closed canopy stands. Hence there are more seedlings growing in open areas.   However, it is not clear whether the results apply for other forest site types as well, and more research is needed.     

• Aaltonen, E-mail: va@mm.unknown

The article presents a survey on distribution of fertile lands, soil types and site classes in Savo and Karelia in the central and eastern parts of Finland. The survey was based both in existing publications and statistics, a line survey, and visual observations during field trips. The site quality classification is based on the vegetation and occurrence of indicator plant species. The article lists distribution of indicator species in different forest site types on maps of the area. In addition, a review of history of land use and agriculture give indications of the location of the fertile lands in the area. A map of the forest site types in different parts of the area illustrate the data collected from the different sources.

The PDF includes a summary in German.

• Lukkala, E-mail: ol@mm.unknown

Soil of open and forest covered lands have different properties. Forest devastation has negative effect on forest soil, for instance, through leaching of nutrients. There are different views on how forest fire influences chemical properties of the soil. Burning of forests can have both positive and negative consequences.

The article publishes partial results from a study that aimed to find out how shifting cultivation affects the soil, and how it may change natural regeneration and forest growth of the stands. Soil samples were collected from four burnt-over sites. Of the samples, size classes of the soil particles, volatile solids and nutrient contents were determined. According to the results, the burning increased soluble nutrients, but the effect was not long-lasting. However, more sample sites would be needed to give definitive results of the differences.

• Heikinheimo, E-mail: oh@mm.unknown

The effect of scarification, ploughing and cross-directional ploughing on temperature conditions in the soil and adjacent air layer have been studied during 11 growth periods by using an unprepared clear-cut area as a control site. The development of seedling stand was followed to determine its shading effect on the soil surface.

Soil preparation decreased the daily temperature amplitude of the air at the height of 10 cm. The maximum temperatures on sunny days were lower in the tilts of the ploughed and in the humps of the cross-directional ploughed sites compared with the unprepared area. Correspondingly, the night temperatures were higher and so the soil preparation reduced the risk of night frost. In the soil at the depth of 5 cm, soil preparation increased daytime temperatures and reduced night temperatures compared with unprepared area. The maximum increase in monthly mean temperatures was almost 5°C, and the daily variation in the surface parts of the tilts and humps increased so that excessively high temperatures for the optimal growth of the root systems were measured from time to time. The temperature also rose at the depths of 50 and 100 cm.

Soil preparation also increased the cumulative temperature sum. The highest sums accumulated during the summer months were recorded at the depth of 5 cm in the humps of cross-directional ploughed area (1,127 dd.) and in the tilts of the ploughed area (1,106 dd.), while the corresponding figure in the unprepared soil was 718 dd. At the height of 10 cm the highest temperature sum was 1,020 dd. in the hump, and 925 dd. in the unprepared area.

The incidence of high temperature amplitudes and frequency of high temperatures at the depth of 5 cm decreased most rapidly in the humps of cross-sectional ploughed area and the ploughing tilts towards the end of the study period. The decrease was attributed principally to the compressing of tilts, the ground vegetation succession and the growth of seedlings. The difference between the prepared and unprepared area did not diminish. The increase in temperature due to soil preparation, thus, lasted at least over 10 years.

• Kubin, E-mail: ek@mm.unknown
• Kemppainen, E-mail: lk@mm.unknown

The present paper deals with the effects of clearcutting on soil and air temperature and the development of temperature conditions during the 12 growing seasons following clearcutting of a Norway spruce (Picea abies (L.) H. Karst.) stand on a Vaccinium-Myrtillus forest type in Kainuu, northeast Finland. The uncut control site had a growing stock of 140 m³/ha. The temperature measurements were carried out by means of thermographs, Grant measuring devices and minimum and maximum glass thermometers.

Clearcutting had no significant influence on temperatures measures at 2 m above the ground in a meteorological screen and no changes occurred in them during the period studied, while on the ground level and in the adjacent layer of air the daily maxima increased and the daily minima decreased as compared with uncut forest. The greatest difference was over 10°C between the maximum temperatures at 10 cm and almost 8°C between the minimum temperatures. Night frosts were considerably more common at 10 cm above the ground in the clearcut area than in uncut forests.

Temperature differences were smaller in the soil than close to ground level. Day temperatures were 2–3°C higher in the clearcut area than in uncut forests, and differences between night temperatures at this depth were even smaller. Correspondingly, temperatures were 3–5°C higher at depths of 50 cm and 100 cm in the clearcut area during the whole measuring period. The differences between the temperatures in the clearcut area and uncut forests did not diminish to any significant extent during the 12 years despite the stocking of the former area with seedlings.

The PDF includes a summary in Finnish.

• Kubin, E-mail: ek@mm.unknown
• Kemppainen, E-mail: lk@mm.unknown

The effect of different fertilizer treatments on the invertebrate fauna on coniferous forest soil were investigated during the years 1979-83 both in field and in laboratory experiments. Fertilizers tested were urea (both alone and with P and K), ammonium nitrate and ashes. Ash-treatment was also controlled by raising the pH at the same level with Ca(OH)₂.

Both ashes and urea resulted in considerable changes in the soil fauna. Nematodes, especially bacterial feeders, increased temporarily. Some families of Coleoptera invaded the urea-treated plots. Enchytraceid worms and several microarthropod species decreased, as well as the total animal biomass. Ash-treatment influenced more slowly than did urea-fertilizing, but it caused more permanent changes. Ammonium nitrate with lime had little influence in the field. All fertilizers affected more strongly when mixed with soil in laboratory. pH alone proved to explain most of the changes observed, but nitrogen as a nutrient also plays role independently of acidity.

The PDF includes a summary in Finnish.

• Huhta, E-mail: vh@mm.unknown
• Hyvönen, E-mail: rh@mm.unknown
• Koskenniemi, E-mail: ak@mm.unknown
• Vilkamaa, E-mail: pv@mm.unknown
• Kaasalainen, E-mail: pk@mm.unknown
• Sulander, E-mail: ms@mm.unknown

The vegetation and number of physical and chemical soil properties were studied on a random sample of closed upland forest stands in Southern Finland. The material consists of a total of 410 sample plots. Two-way indicator species analysis (TWINSPAN) was carried out in order to produce a hierarchical clustering of samples on the basis of the vegetation data. Discriminant analysis and analysis of variance were applied in order to find environmental correlations of the vegetation clustering.

The vegetation was found to indicate the nutrient regime of the humus layer well, but to a less extent the properties of the sub-soil. The understorey vegetation was found to be jointly dependent on the site fertility and on the properties of the tree stand, especially on the tree species composition. Although the forest vegetation appears to be distributed rather continuously along an axis of increasing site fertility, relatively unambiguous classification can be based on the appearance of indicator species and species groups.

The results of the study were interpreted as indication that operational site classification done using the vegetation is rather good method for classification in closed forest stands. Different methods produce relatively consistent, natural and ecologically interpretable classifications. The results also imply that the vegetation cover and the humus layer develop concurrently during the development of the ecosystem, but the differentiation of the site type is regulated simultaneously by a number of interacting factors ranging from mineralogical properties of the parent material to the topographical exposition of the site. As the plant cover depicts all these primary factors simultaneously, only a relatively rough ecological site classification can be based on the vegetation.

The PDF includes a summary in Finnish.

• Kuusipalo, E-mail: jk@mm.unknown

Soil respiration readings are reported for three ameliorated peatland sites of different types, covering a period of four years, during which the sites were drained and treated with various fertilizers. Respiration is shown to increase exponentially with temperature, varying mostly in the range 100–500 mg CO² m^-2 h^-1. The changes in soil respiration followed those in surface temperature with a time-lag of approximately 3–3.5 hours. At one site, where the groundwater table dropped by about 0.5 m after ditching, soil respiration increased 2.5-fold within a few weeks, whereas at the other two sites both the fall in the groundwater table and the resultant changes in soil respiration were small.

The fertilizers tested were slow-dissolving PK, fast-dissolving PK, wood ash, slow-dissolving PK + urea, slow-dissolving PK + Nitroform (urea formaldehyde) and slow-dissolving PK + urea + a micro-element mixture. Application of fast-dissolving PK + urea led to a rapid increase in soil respiration at the site poorest in nutrients, and slow-dissolving PK to a slow increase in respiration. The greatest, steady increase of all was achieved by treatment with ash. At the sites with a higher natural nutrient content the application of fertilizers usually led to a decline in soil respiration lasting 1–2 years, after which the initial level was normally regained. Treatment with micro-elements caused an initial fall in soil respiration values in all three biotopes, followed by a pronounced increase.

The PDF includes a summary in Finnish.

• Silvola, E-mail: js@mm.unknown
• Välijoki, E-mail: jv@mm.unknown
• Aaltonen, E-mail: ha@mm.unknown

The aims of the present study were to determine physical and physio-chemical properties of some Finnish forest tree nursery soils, and to examine relationships between these properties and the amount of organic matter in the soil.

The following soil tillage layer properties of 33 fields belonging to 8 forest tree nurseries were determined: soil particle size distribution, organic matter content, bulk density and density of solids, total pore space, soil water volume at potentials pF 2.0 and 4.2, available water content and air space at potential pF 2.0, active acidity, electrical conductivity index and cation exchange capacities at pH 4.5 and 8.0. The soil texture class of the tillage layer parent material was sand, only in a few cases did higher percentage of silt and clay indicate a morainic nature of parent material. The amount of organic material in the soils varied within wide limits, reflecting differences in amelioration policy between the single nurseries.

Relationships between the physical properties of the soil parent material and those related to fertility were in most cases strongly influenced by the amount of soil organic matter. Soil density values decreased as the organic matter content increased from 2 to 25%, giving rise to the increase in the total pore space. However, the amount of water held at potential pF 2.0 and the available water content did not increase with increasing organic matter content. This was due to the absence of the particle fraction in the sand. Nursery soil amelioration, involving in most cases a mixture of Sphagnum peat with sand, thus gives rise to an increase in the content of drainable water.

Cation exchange capacities were positively correlated with the organic matter content. However, the absolute number of exchange sites expressed as equivalents in the tillage layer did not increase in accordance with the increase in organic matter content due to the influence of the organic matter content upon the ratio of solids in the voids.

The PDF includes a summary in English.

• Westman, E-mail: cw@mm.unknown

Residue of the wood is good raw material for pulp and board industries, but the question of the use of barking waste still remains to a great extent unsolved. This research deals with the possibilities to utilize the barking waste of sawmill industry in general and, in particular, its use as a soil improver and substrate for plants. It also explains the industrial manufacturing method of composted bark, bark humus, developed by the author as well as the properties of bark humus and the economy of bark humus and the economy of manufacturing.

The PDF includes a summary in Finnish.

• Isomäki, E-mail: oi@mm.unknown

• Peltoniemi, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: mikko.peltoniemi@metla.fi
• Thürig, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, Switzerland; European Forest Institute, Joensuu, Finland E-mail: et@nn.ch
• Ogle, Natural Resources Ecology Laboratory, Colorado State University, Fort Collins, USA E-mail: so@nn.us
• Palosuo, European Forest Institute, Joensuu, Finland E-mail: tp@nn.fi
• Schrumpf, Max-Planck-Institute for Biogeochemistry, Jena, Germany E-mail: ms@nn.de
• Wutzler, Max-Planck-Institute for Biogeochemistry, Jena, Germany E-mail: tw@nn.de
• Butterbach-Bahl, Institute for Meteorology and Climate Research, Forschungszentrum Karlsruhe GmbH, Garmisch-Partenkirchen, Germany E-mail: kbb@nn.de
• Chertov, St. Petersburg State University, St. Petersburg-Peterhof, Russia E-mail: oc@nn.ru
• Komarov, Institute of Physicochemical and Biological Problems in Soil Science of Russian Academy of Sciences, Pushchino, Russia E-mail: ak@nn.ru
• Mikhailov, Institute of Physicochemical and Biological Problems in Soil Science of Russian Academy of Sciences, Pushchino, Russia E-mail: am@nn.ru
• Gärdenäs, Dept. of Soil Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden E-mail: ag@nn.se
• Perry, USDA Forest Service, Northern Research Station, St. Paul, MN USA E-mail: cp@nn.us
• Liski, Finnish Environment Institute, Helsinki, Finland E-mail: jl@nn.fi
• Smith, School of Biological Sciences, University of Aberdeen, Aberdeen, UK E-mail: ps@nn.uk
• Mäkipää, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: raisa.makipaa@metla.fi

• Wutzler, Max Planck Institute for Biogeochemistry, Jena, Germany E-mail: tm@nn.de
• Mund, Max Planck Institute for Biogeochemistry, Jena, Germany E-mail: mm@nn.de

• Peltoniemi, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: mikko.peltoniemi@metla.fi
• Heikkinen, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: jh@nn.fi
• Mäkipää, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: raisa.makipaa@metla.fi

Impact of drainage of organic soils in forest land on soil carbon (C) stock changes is of high interest not only to accurately estimate soil C stock changes, but also to provide scientifically based recommendations for forest land management in context of climate change mitigation. To improve knowledge about long-term impact of drainage on nutrient-rich organic soils in hemiboreal forests in Latvia, 50 research sites representing drained conditions (Oxalidosa turf. mel. (Kp) and Myrtillosa turf. mel. (Ks) forest site types) and undrained conditions as control areas (Caricoso-phragmitosa, Dryopterioso-caricosa and Filipendulosa forest site types) were selected. Soil C stock changes after drainage was evaluated by comparing current C stock in drained organic soils to theoretical C stock before drainage considering impact of soil subsidence. During the 53-years period after drainage, the peat subsidence was higher in nutrient-rich Kp forest site type compared to moderate nutrient-rich Ks forest site type (peat subsided by 37.0 ± 4.8 and 23.3 ± 4.8 cm, respectively). In nutrient-rich Kp forest site type, soil C stock decreased by 4.98 ± 1.58 Mg C ha^-1 yr^-1 after drainage, while no statistically significant changes in soil C stock (0.19 ± 1.31 Mg C ha^-1 yr^-1) were observed in moderate nutrient-rich soils in Ks forest site type. Thus, in Ks forest site type, the main driver of the peat subsidence was the physical compaction, while in Kp forest site type contribution of organic matter decomposition and consequent soil C losses to subsidence of the peat was significant.

• Lazdiņš, Latvian State Forest Research Institute ‘Silava’ (LSFRI Silava), Rigas str. 111, Salaspils, LV-2169, Latvia https://orcid.org/0000-0002-7169-2011 E-mail: andis.lazdins@silava.lv
• Lupiķis, Latvian State Forest Research Institute ‘Silava’ (LSFRI Silava), Rigas str. 111, Salaspils, LV-2169, Latvia E-mail: ainars.lupikis@inbox.lv
• Polmanis, Latvian State Forest Research Institute ‘Silava’ (LSFRI Silava), Rigas str. 111, Salaspils, LV-2169, Latvia https://orcid.org/0000-0003-2579-353X E-mail: kaspars.polmanis@silava.lv
• Bārdule, Latvian State Forest Research Institute ‘Silava’ (LSFRI Silava), Rigas str. 111, Salaspils, LV-2169, Latvia https://orcid.org/0000-0003-0961-5119 E-mail: arta.bardule@silava.lv
• Butlers, Latvian State Forest Research Institute ‘Silava’ (LSFRI Silava), Rigas str. 111, Salaspils, LV-2169, Latvia https://orcid.org/0000-0003-3118-1716 E-mail: aldis.butlers@silava.lv
• Kalēja, Latvian State Forest Research Institute ‘Silava’ (LSFRI Silava), Rigas str. 111, Salaspils, LV-2169, Latvia E-mail: santa.kaleja@silava.lv

In southern Lapland, 70% of drained peatland forests have a peat layer thickness of less than one metre. On these sites, the question is how the subsoil under the peat affects groundwater level and thus timber harvesting. The aim of this study was to investigate the effect of the peat layer (<1 m) and subsoil on the groundwater level and its variation during the growing season (non-frost) by modelling the factors affecting water level. In sandy soils, the groundwater level rose by 20 cm when the peat layer thickness increased from 20 to 70 cm. In silty soils the effect of the peat thickness on groundwater remained minor. When the subsoil was sand or coarser, the groundwater level was usually deeper than when it was silty or finer. The effect of stand volume (m^–3 ha^–1) on the groundwater level was rather weak albeit significant. The model explained a significant part of the groundwater surface variation, with a marginal coefficient of determination (R²) of 68%. It seems that the rutting of roads could be avoided in late summer if the precipitation is remarkably lower during that period, or if the subsoil is sandy with thin peat layer on top of it. Because the groundwater level affects the load-bearing capacity of timber-harvesting machinery, it is important to study this issue in more detail in the future.

• Hiltunen, Lapland University of Applied Sciences, Jokiväylä 11, FI-96300 Rovaniemi, Finland E-mail: oivah@student.uef.fi
• Hallikainen, Natural Resources Institute Finland, Ounasjoentie 6, FI-96300 Rovaniemi, Finland E-mail: ville.hallikainen@luke.fi
• Palander, The University of Eastern Finland, Faculty of Science, Forestry and Technology, P.O. Box 111, FI-80101 Joensuu, Finland https://orcid.org/0000-0002-9284-5443 E-mail: teijo.s.palander@uef.fi

This study’s aim was to calculate the weathering rates of Ca and Mg for five boreal forest soils in southern Finland on granitic and gabbro containing bedrock. The effect of mineralogy on the total concentrations of Ca and Mg in soil and weathering rates was evaluated. The aim was also to estimate the effect of mechanical soil disturbance related to ploughing on the weathering in the gabbro area. The total concentrations of SiO₂, CaO, MgO, and Zr were determined by XRF, and weathering rates of Ca and Mg were determined based on the changes in the CaO, MgO, and Zr concentrations. The weathering rates of Ca+Mg varied 5–38 mmol_c m^–2 year^–1 in the E+B/BC horizons among the plots. Soil disturbance related to ploughing increased the weathering of Ca and Mg largely in the disturbed part of the topmost mineral soil as indicated by the decreasing concentrations of Ca and Mg after mechanical soil disturbance. The weathering input of Ca in the undisturbed soil did not fully replace the Ca output in final whole-tree cutting. The weathering input of Mg in the undisturbed soil was sufficient to replace the lost Mg in stemwood harvesting but not on all the plots the lost Mg in whole-tree harvesting. Weathering rates were higher in the gabbro than the granitic areas.

• Lindroos, Natural Resources Institute Finland (Luke), Natural resources, Latokartanonkaari 9, FI-00790 Helsinki, Finland E-mail: antti.lindroos@luke.fi
• Ilvesniemi, Natural Resources Institute Finland (Luke), Production systems, Latokartanonkaari 9, FI-00790 Helsinki, Finland E-mail: hannu.ilvesniemi@luke.fi

Mechanical site preparation (MSP) is a common practice that precedes the planting of Norway spruce (Picea abies (L.) H. Karst.) in Nordic forests. Mounding has become the most used method in spruce planting in recent years. This study examined the effects of different mounding treatments (spot and ditch mounding, inversion, unprepared control with or without herbicide application) and a mechanical vegetation control (MVC) treatment done 3–4 years after planting on the post-planting growth of spruce container seedlings and their development to saplings during the first 11–13 years on two forest till soils in central Finland, one on flat terrain and other on a southwest slope. On these fine-textured soils the spot and ditch mounding methods favoured spruce saplings development. Inversion and unprepared plots showed weakest growth. On the site with flat terrain, 11 years post planting, spruce saplings were 78–144 cm (38–80%) taller and their breast height diameters were 11–13 mm (60–74%) thicker for ditch or spot mounding than for inversion or herbicide treatment. On the site with sloped terrain the differences were minor between the MSP treatments. MVC improved spruce height growth on sites which did not have intensive MSP, especially on control saplings planted on unprepared soil in herbicide and inversion treatments. On the flat terrain, MVC reduced the density of resprouts to be removed later in pre-commercial thinning. As a conclusion, spot or ditch mounding favoured the growth of spruce over inversion especially on flat terrain with fine-textured soil.

• Uotila, Natural Resources Institute Finland (Luke), Natural resources, Juntintie 154, FI-77600 Suonenjoki, Finland E-mail: karri.uotila@luke.fi
• Luoranen, Natural Resources Institute Finland (Luke), Natural resources, Juntintie 154, FI-77600 Suonenjoki, Finland https://orcid.org/0000-0002-6970-2030 E-mail: jaana.luoranen@luke.fi
• Saksa, Natural Resources Institute Finland (Luke), Natural resources, Juntintie 154, FI-77600 Suonenjoki, Finland https://orcid.org/0000-0002-1776-2357 E-mail: timo.saksa@luke.fi
• Laine, Metsä Forest, Revontulenpuisto 2, FI-02100 Espoo, Finland https://orcid.org/0000-0002-6448-8274 E-mail: tiina.laine@metsagroup.com
• Heiskanen, Natural Resources Institute Finland (Luke), Natural resources, Juntintie 154, FI-77600 Suonenjoki, Finland https://orcid.org/0000-0002-0549-835X E-mail: juha.heiskanen@luke.fi

Cable yarding is a general solution for load handling on sites not accessible to ground-based machinery, and is typically associated with steep terrain. On flat terrain, such conditions can primarily be found on soft or wet soils, most frequently encountered in Central and Northern European countries. Today, changed environmental and market conditions may offer an unprecedented opportunity to the actual implementation of cable yarding on flat terrain in commercial operations. The study goal was to collect cable yarder manufacturers experience regarding the use and adaption of cable yarding technology on flat terrain. European manufacturers of cable yarding technology were interviewed about customer experience, particular challenges, adaptation potential, future potential and main hurdles for the expansion of cable yarding on flat terrain. Almost all manufacturers have received requests for flat-terrain yarding technology solutions, primarily from Germany. Temporal or permanent inaccessibility, regulatory or environmental reasons were the most frequent motivation for considering cable yarding technology. Installation was considered particularly challenging (clearance, stable anchoring). Potential adaptations included higher towers, artificial anchors, mechanized bunching before extraction and un-guyed yarder-systems. An artificial, highly mobile, self-anchoring tail spar was considered the most useful adaptation. While concerned about limited profitability and qualified labour shortage, most manufacturers demonstrated a positive or neutral view concerning the expansion of cable yarding on flat terrain. However, cable yarding is not considered to be cost-competitive wherever ground-based systems can be employed and cable yarding is not subsidized.

• Erber, University of Natural Resources and Life Sciences Vienna, Department of Forest and Soil Sciences, Institute of Forest Engineering, Peter Jordan Strasse 82, 1190 Vienna, Austria https://orcid.org/0000-0003-1606-5258 E-mail: gernot.erber@boku.ac.at
• Spinelli, CNR-IBE Consiglio Nazionale delle Ricerche-Istituto per la BioEconomia, Via Madonna del Piano 10, Sesto Fiorentino, Firenze, I-50019, Italy; AFORA, University of the Sunshine Coast, Locked Bag 4, Maroochydore, QLD, Australia https://orcid.org/0000-0001-9545-1004 E-mail: spinelli@ivalsa.cnr.it

Considering the increasing use of wood biomass for energy and the related intensification of forest management, the impacts of different intensities of biomass harvesting on nutrient leaching risks must be better understood. Different nitrogen forms in the soil solution were monitored for 3 to 6 years after harvesting in hemiboreal forests in Latvia to evaluate the impacts of different biomass harvesting regimes on local nitrogen leaching risks, which potentially increase eutrophication in surface waters. In forestland dominated by Scots pine Pinus sylvestris L. or Norway spruce Picea abies L. (Karst.), the soil solution was sampled in: (i) stem-only harvesting (SOH), (ii) whole‐tree harvesting, with only slash removed (WTH), and (iii) whole‐tree harvesting, with both slash and stumps harvested (WTH + SB), subplots. In agricultural land, sampling was performed in an initially fertilised hybrid aspen (Populus tremula L.× P. tremuloides Michx.) short-rotation coppice (SRC), where above-ground biomass was harvested. In forestland, soil solution N (nitrogen) concentrations were highest in the second and third year after harvesting. Mean annual values in WTH subplots of medium to high fertility sites exceeded the mean values in SOH subplots and control subplots (mature stand where no harvesting was performed) for the entire study period; the opposite trend was observed for the low-fertility site. Biomass harvesting in the hybrid aspen SRC only slightly affected NO₃^–-N (nitrate nitrogen) and NH₄⁺-N (ammonium nitrogen) concentrations in the soil solution within 3 years after harvesting, but a significant decrease in the TN (total nitrogen) concentration in the soil solution was found in plots with additional N fertilisation performed once initially.

• Kļaviņš, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia; University of Latvia, Raiņa blvd 19-125, LV 1586, Riga, Latvia E-mail: ivars.klavins@silava.lv
• Bārdule, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia; University of Latvia, Raiņa blvd 19-125, LV 1586, Riga, Latvia E-mail: arta.bardule@silava.lv
• Lībiete, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia E-mail: zane.libiete@silava.lv
• Lazdiņa, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia E-mail: dagnija.lazdina@silava.lv
• Lazdiņš, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia E-mail: andis.lazdins@silava.lv

Factors affecting soil disturbance caused by harvester and forwarder were studied on mid-grained soils in Finland. Sample plots were harvested using a one-grip harvester. The harvester operator processed the trees outside the strip roads, and the remaining residues were removed to exclude the covering effect of residues. Thereafter, a loaded forwarder made up to 5 passes over the sample plots. The average rut depth after four machine passes was positively correlated to the volumetric water content at a depth of 0–10 cm in mineral soil, as well as the thickness of the organic layer and the harvester rut depth, and negatively correlated with penetration resistance at depths of both 0–20 cm and 5–40 cm. We present 5 models to predict forwarder rut depth. Four include the cumulative mass driven over a measurement point and combinations of penetration resistance, water content and the depth of organic layer. The fifth model includes harvester rut depth and the cumulative overpassed mass and provided the best fit. Changes in the penetration resistance (PR) were highest at depths of 20–40 cm. Increase in BD and VWC decreased PR, which increased with total overdriven mass. After four to five machine passes PR values started to stabilize.

• Sirén, Natural Resources Institute Finland (Luke) c/o Aalto University, P.O. Box 15600, FI-00076 Aalto, Finland E-mail: matti.siren@luke.fi
• Ala-Ilomäki, Natural Resources Institute Finland (Luke) c/o Aalto University, P.O. Box 15600, FI-00076 Aalto, Finland http://orcid.org/0000-0002-6671-7624 E-mail: jari.ala-ilomaki@luke.fi
• Lindeman, Natural Resources Institute Finland (Luke), Korkeakoulunkatu 7, FI-33720 Tampere, Finland E-mail: harri.lindeman@luke.fi
• Uusitalo, Natural Resources Institute Finland (Luke), Korkeakoulunkatu 7, FI-33720 Tampere, Finland http://orcid.org/0000-0003-3793-1215 E-mail: jori.uusitalo@luke.fi
• Kiilo, Versowood, Teollisuuskatu 1, FI-11130 Riihimäki, Finland E-mail: kalle.kiilo@versowood.fi
• Salmivaara, Natural Resources Institute Finland (Luke), P.O. Box 2, FI-00791 Helsinki, Finland E-mail: aura.salmivaara@luke.fi
• Ryynänen, Natural Resources Institute Finland (Luke), Kaironiementie 15, FI-39700 Parkano, Finland E-mail: ari.ryynanen@luke.fi

The strength of soil is known to be dependent on water content but the relationship is strongly affected by the type of soil. Accurate moisture content – soil strength models will provide forest managers with the improved ability to reduce soil disturbances and increase annual forest machine utilization rates. The aim of this study was to examine soil strength and how it is connected to the physical properties of fine-grained forest soils; and develop models that could be applied in practical forestry to make predictions on rutting induced by forest machines. Field studies were conducted on two separate forests in Southern Finland. The data consisted of parallel measurements of dry soil bulk density (BD), volumetric water content (VWC) and penetration resistance (PR). The model performance was logical, and the results were in harmony with earlier findings. The accuracy of the models created was tested with independent data. The models may be regarded rather trustworthy, since no significant bias was found. Mean absolute error of roughly 20% was found which may be regarded as acceptable taken into account the character of the penetrometer tool. The models can be linked with mobility models predicting either risks of rutting, compaction or rolling resistance.

• Uusitalo, Natural Resources Institute Finland (Luke), Production systems, Korkeakoulunkatu 7, FI-33720 Tampere, Finland E-mail: jori.uusitalo@luke.fi
• Ala-Ilomäki, Natural Resources Institute Finland (Luke), Production systems Maarintie 6, FI-02150 Espoo, Finland E-mail: jari.ala-ilomaki@luke.fi
• Lindeman, Natural Resources Institute Finland (Luke), Production systems, Korkeakoulunkatu 7, FI-33720 Tampere, Finland E-mail: harri.lindeman@luke.fi
• Toivio, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: toiviojenny@gmail.com
• Siren, Natural Resources Institute Finland (Luke), Production systems Maarintie 6, FI-02150 Espoo, Finland E-mail: matti.siren@luke.fi

Hybrid aspen (Populus tremula L. × P. tremuloides Michx.) is a deciduous tree species suitable for producing large amounts of renewable biomass during short rotations. Its potential under North European conditions could be largely extended if not only agricultural land but also forest land was used for cultivation. Unfortunately, the knowledge of appropriate forest site conditions and effects of site preparation methods on hybrid aspen establishment is limited. In this paper, two studies that explore these questions are presented. In the first study, the sensitivity to acid soils was tested under greenhouse conditions in two type of soils: a) peat soil limed to certain pH levels (3.4–5.7) and b) collected forest soils where pH varied from 3.9 to 5.3. The lowest pH level resulted in reduced growth, elsewhere no significant differences were found. The second study was applied in the field and investigated the effect of four site preparation methods on survival and growth. The methods were: 1) control with no site preparation, 2) patch scarification, 3) mounding and 4) soil inversion. While no differences were found for survival, mounding was generally the method with the highest growth and patch scarification was least successful. The result was probably an effect of good soil aeration and less competition from vegetation after mounding. The field study also revealed clonal differences in growth performance, which stresses the importance of clone selection prior to planting. The results of these studies indicate that hybrid aspen is less sensitive to variation in pH and site preparation methods compared with other poplar species, as have been found in similar studies.

• Hjelm, Skogforsk, Ekebo 2250, SE-268 90 Svalöv, Sweden E-mail: karin.hjelm@skogforsk.se
• Rytter, Skogforsk, Ekebo 2250, SE-268 90 Svalöv, Sweden http://orcid.org/0000-0001-6183-4832 E-mail: lars.rytter@skogforsk.se

Operating conditions affecting the quality of spot mounding by Bracke continuously advancing mounders were investigated on 66 regeneration areas (124 ha) in eastern Finland. The quality of mounds was classified as suitable (good or acceptable after additional compression) or unsuitable for planting. Models were constructed for the number of suitable planting spots obtained per hectare (good and acceptable mounds), the probability of successful mounding (≥1600 planting spots ha^–1) and the probability of creating a suitable mound as a function of terrain, site and soil characteristics, as well as slash conditions (removed, fresh or dry logging residues). The average number of mounds created was 1892 ± 290 mounds ha^–1, of which 1398 ± 325 mounds ha^–1 (74%) were classified as suitable for planting. The quality of spot mounding was reduced by steep terrain, a thick humus layer and fresh logging residues. Stoniness and soil texture also affected the number of planting spots created. Mounding after logging residues had dried increased the number of planting spots by 191 spots ha^–1 compared with mounding in the presence of fresh residues. Removing residues did not significantly increase the number of planting spots compared with mounding amongst dry residues. A thick humus layer, very stony soil, steep slopes and valley terrain decreased the number of planting spots by 150–450 spots ha^–1. The number and quality of mounds varied considerably according to the operating conditions, but with careful selection of timing and sites the quality obtained by a continuously advancing mounder can be improved.

• Saksa, Natural Resources Institute Finland (Luke), Juntintie 154, FI-77600 Suonenjoki, Finland E-mail: timo.saksa@luke.fi
• Miina, Natural Resources Institute Finland (Luke), Yliopistokatu 6, FI-80100 Joensuu, Finland E-mail: jari.miina@luke.fi
• Haatainen, Faculty of Science and Forestry, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: hilkka.haatainen@storaenso.com
• Kärkkäinen, Tornator Oyj, Muuntamontie 2, FI-80100 Joensuu, Finland E-mail: kauko.karkkainen@tornator.fi

In this study we determined the effect of transformation of a mature sessile oak forest stand into a coppiced forest, and of thinning and throughfall reduction in a coppice stand on soil water content (SWC) and soil CO₂ efflux. The precipitation reduction was induced by installing parallel drainage channels in both unthinned and thinned coppice stands. The driving factor for temporal dynamics of soil CO₂ efflux in all plots was soil temperature. The other factor was soil water content but only up to about 15%. Above this threshold, there was no more effect on CO₂ efflux. We found no clear difference in SWC or soil CO₂ efflux between the mature and coppiced stand eight years after harvesting. On the other hand, thinning of the coppice stand resulted in increase in SWC up to 22% in proportion, which we assume to be a result of increased gap fraction of the canopy. However, no effect on soil CO₂ efflux was observed two years after the thinning. Installation of the drainage channels in two plots covering 30% of the ground area resulted in decrease in SWC up to a proportional 30.5% and thus contributed up to 50.7% reduction in soil CO₂ efflux.

• Dařenová, Global Change Research Institute CAS, v.v.i., Belidla 4a, 603 00 Brno, Czech Republic E-mail: darenova.e@czechglobe.cz
• Crabbe, Global Change Research Institute CAS, v.v.i., Belidla 4a, 603 00 Brno, Czech Republic E-mail: crabbe.r@czechglobe.cz
• Knott, Mendel University in Brno, Zemedelska 3, 613 00 Brno, Czech Republic E-mail: robert.knott@mendelu.cz
• Uherková, Mendel University in Brno, Zemedelska 3, 613 00 Brno, Czech Republic E-mail: xfedorov@node.mendelu.cz
• Kadavý, Mendel University in Brno, Zemedelska 3, 613 00 Brno, Czech Republic E-mail: jan.kadavy@mendelu.cz

• Haataja, Natural Resources Institute Finland (Luke), Natural resources, Juntintie 154, FI-77600 Suonenjoki, Finland E-mail: lauritapiohaataja@gmail.com
• Kankaanhuhta, Natural Resources Institute Finland (Luke), Natural resources, Juntintie 154, FI-77600 Suonenjoki, Finland E-mail: ville.kankaanhuhta@luke.fi
• Saksa, Natural Resources Institute Finland (Luke), Natural resources, Juntintie 154, FI-77600 Suonenjoki, Finland E-mail: timo.saksa@luke.fi

The pine weevil Hylobius abietis L. is an economically important pest insect that kills high proportions of conifer seedlings in reforestation areas. It is present in conifer forests all over Europe but weevil abundance and risk for damage varies considerably between areas. This study aimed to obtain a useful model for predicting damage risks by analyzing survey data from 292 regular forest plantations in northern Sweden. A model of pine weevil attack was constructed using various site characteristics, including both climatic factors and factors related to forest management activities. The optimal model was rather imprecise but showed that the risk of pine weevil attack can be predicted approximatively with three principal variables: 1) the proportion of seedlings expected to be planted in mineral soil rather than soil covered with duff and debris, 2) age of clear-cut at the time of planting, and 3) calculated temperature sum at the location. The model was constructed using long-run average temperature sums for epoch 2010, and so effects of climate change can be inferred from the model by adjustment to future epochs. Increased damage risks with a warmer climate are strongly indicated by the model. Effects of a warmer climate on the geographical distribution and abundance of the pine weevil are also discussed. The new tool to better estimate the risk of damage should provide a basis for foresters in their choice of countermeasures against pine weevil damage in northern Europe.

• Nordlander, Swedish University of Agricultural Sciences (SLU), Department of Ecology, P.O. Box 7044, SE-750 07 Uppsala, Sweden E-mail: Goran.Nordlander@slu.se
• Mason, University of Canterbury, School of Forestry, Private Bag 4800, Christchurch 8140, New Zealand; Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 49, SE-230 53 Alnarp, Sweden http://orcid.org/0000-0001-9024-9106 E-mail: euan.mason@canterbury.ac.nz
• Hjelm, Skogforsk, The Forest Research Institute of Sweden, Ekebo 2250, SE-268 90 Svalöv, Sweden; Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 49, SE-230 53 Alnarp, Sweden E-mail: karin.hjelm@skogforsk.se
• Nordenhem, Swedish University of Agricultural Sciences (SLU), Department of Ecology, P.O. Box 7044, SE-750 07 Uppsala, Sweden E-mail: h.nordenhem@telia.com
• Hellqvist, Swedish University of Agricultural Sciences (SLU), Department of Ecology, P.O. Box 7044, SE-750 07 Uppsala, Sweden E-mail: Claes.Hellqvist@slu.se

Rut formation caused by logging operations has been recognised as a challenge for Swedish forestry. Frequent traffic with heavy machines on extraction roads, together with a warmer climate, is one of the factors that increases the risk of rut formation in forests. One possible way to control this impact of logging operations is to design and apply decision support tools that enable operators to take sensitive areas into account when planning extraction roads. In this study, 16 different logging sites in south-eastern Sweden were surveyed after clear-cut. Information was collected about extraction roads (i.e. traffic intensity, whether the roads had been reinforced with slash) and ruts. Digital maps such as cartographic depth-to-water (DTW) index and soil type were also examined for any connection to rut positions. Soil type and traffic intensity were found to be significant factors in rut formation, while DTW and slash reinforcement were not. However, the DTW map combined with other information, such as soil type, could contribute to decision support tools that improve planning of extraction roads.

• Mohtashami, The forestry research institute of Sweden, Skogforsk, Uppsala Science Park, SE-751 83 Uppsala, Sweden E-mail: sima.mohtashami@skogforsk.se
• Eliasson, The forestry research institute of Sweden, Skogforsk, Uppsala Science Park, SE-751 83 Uppsala, Sweden http://orcid.org/0000-0002-2038-9864 E-mail: lars.eliasson@skogforsk.se
• Jansson, The forestry research institute of Sweden, Skogforsk, Uppsala Science Park, SE-751 83 Uppsala, Sweden http://orcid.org/0000-0002-3018-9161 E-mail: gunnar.jansson@skogforsk.se
• Sonesson, The forestry research institute of Sweden, Skogforsk, Uppsala Science Park, SE-751 83 Uppsala, Sweden http://orcid.org/0000-0002-2018-7496 E-mail: johan.sonesson@skogforsk.se

We describe here a study based on analysis of vegetation indices and land surface temperatures, which provides relevant information for estimating soil moisture at regional scales. Through an analysis of MODIS satellite imagery and in situ moisture data, the triangle method was used to develop a conceptual land surface temperature−vegetation index model, and spatial temperature-vegetation dryness index (TVDI) values to describe soil moisture relationships for a broad landscape. This study was situated mainly within two states of the southern United States (Georgia and South Carolina). The total study area was about 30 million hectares. The analyses were conducted using information gathered from the 2009 growing season (from the end of March to September). The results of the study showed that soil moisture content was inversely proportional to TVDI, and that TVDI based on the normalized difference vegetation index (NDVI) had a slightly higher correlation with soil moisture than TVDI based on the enhanced vegetation index (EVI).

• Przeździecki, Warsaw University of Technology, Faculty of Building Services, Hydro and Environmental Engineering, 00-653, Nowowiejska 20, Warszawa, Poland http://orcid.org/0000-0002-2275-5223 E-mail: karol_przezdziecki@is.pw.edu.pl
• Zawadzki, Warsaw University of Technology, Faculty of Building Services, Hydro and Environmental Engineering, 00-653, Nowowiejska 20, Warszawa, Poland http://orcid.org/0000-0003-2842-0018 E-mail: j.j.zawadzki@gmail.com
• Cieszewski, University of Georgia, Warnell School of Forestry and Natural Resources, 180 E Green St, Athens, GA 30602, USA http://orcid.org/0000-0003-2842-4406 E-mail: thebiomat@gmail.com
• Bettinger, University of Georgia, Warnell School of Forestry and Natural Resources, 180 E Green St, Athens, GA 30602, USA http://orcid.org/0000-0002-5454-3970 E-mail: pbettinger@warnell.uga.edu

Different environmental factors were studied to determine which factors influence the species richness, composition and structure of vascular plants in Pinus sylvestris L. forests in a fixed dune landscape in south-western Estonia. In addition to site topographic factors, different environmental parameters were investigated. Thirty-four vascular plant species were recorded in 232 quadrats. The most abundant species was Vaccinium vitis-idaea L., which was in 82.8% of quadrats, followed by Vaccinium myrtillus L. (74.1%), Melampyrum pratense L. (71.1%) and Deschampsia flexuosa (L.) Trin. (69.8%). The multiple response permutation procedure (MRPP) showed considerable differences in species composition at the bottoms of dunes compared with that on the slopes and at the tops of dunes. Indicator species analysis (ISA) determined species exhibited characteristics specific to zone: V. myrtillus had the highest indicator value at the bottoms of dunes; Calluna vulgaris L., at the tops. Soils were Haplic Podzols, and the presence of humus horizon depended on zone. Soil conditions on the dunes were variable and site specific, in general, soils at the bottoms of the dunes were more acidic and moist compared with those of the slopes and tops of the dunes, and the nutrient content decreased toward the dune tops. According to non-metric multidimensional scaling (NMDS) and linear mixed model analyses, species coverage, composition and richness were controlled by site-specific factors such as absolute height, location and aspect of the quadrat on the dune; soil nitrogen, potassium and phosphorus contents; soil pH and moisture; light conditions; and the thickness of the litter horizon.

• Tilk, Department of Silviculture, Estonian University of Life Sciences, Kreutzwaldi 5, Tartu, Estonia, 51014; Tallinn Botanic Garden, Kloostrimetsa Road 52, Tallinn, Estonia, 11913 E-mail: Mari.Tilk@botaanikaaed.ee
• Tullus, Department of Silviculture, Estonian University of Life Sciences, Kreutzwaldi 5, Tartu, Estonia, 51014 E-mail: Tea.Tullus@emu.ee
• Ots, Department of Silviculture, Estonian University of Life Sciences, Kreutzwaldi 5, Tartu, Estonia, 51014 E-mail: Katri.Ots@emu.ee

The impacts of weed control, ash fertilization and their interaction were tested for the afforestation of former agricultural peat-based soil with Scots pine (Pinus sylvestris L.) in northern Finland in a factorial arrangement of four treatments. Weed control with herbicides was carried out in July 1 and 2 years from planting, and wood ash (5 Mg ha^–1) was applied in the spring of the 2nd year. Various vegetation, tree growth and nutrient assessments were made over the 21-year study period. Weed control decreased the weed cover by 36–56 percentage points, vegetation height by 4–26 cm and thus shading of seedlings by vegetation for at least 4 years after planting. For the same period, ash fertilization increased vegetation height by 6–15 cm and shading of seedlings. Weed control reduced seedling mortality by 27 percentage points in 21 years, but ash fertilization had no significant effect. Ash fertilization increased foliar potassium and boron concentrations, but its effect declined, and severe K-deficiency was recorded 21 years after planting. Up to the 9th year, weed control had a greater influence on growth than fertilization. Later the significance of fertilization increased due to an aggravated K-deficiency. Stand volume at year 21 for the untreated control plots was 8 m³ ha^–1. Weed control and fertilization increased stand volume by 20 and 35 m³ ha^–1, with a combined effect of 55 m³ ha^–1. The effects of weed control and fertilization were additive and no significant interactions were found. Due to severe K-deficiencies, re-fertilization of all treatments would be necessary for the continued survival and growth of Scots pine.

• Hytönen, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, Teknologiakatu 7, FI-67100 Kokkola, Finland http://orcid.org/0000-0001-8475-3568 E-mail: jyrki.hytonen@luke.fi
• Jylhä, Natural Resources Institute Finland (Luke), Green technology, Teknologiakatu 7, FI-67100 Kokkola, Finland E-mail: paula.jylha@luke.fi
• Little, Nelson Mandela Metropolitan University, George Campus, Western Cape, South Africa E-mail: keith.little@nmmu.ac.za

A significant amount of land area in the Central Anatolian Region of Turkey has saline-sodic soil properties. The aim of the current study was to use both soil amendment and tree to restore these degraded lands. The primary objective was to ameliorate soils by leaching excess sodium with gypsum and sulfur applications. Following soil treatments, salt cedar (Tamarix smyrnensis Bunge), Russian olive (Elaeagnus angustifolia L.) and silver poplar (Populus alba L.) seedlings were planted on experimental and control sites to evaluate the effects of the treatments on survival and growth of these species. In the fall of 2013, three-year-old seedlings were planted using 1.5 × 1.5 m spacing on each plot. Survival rates were determined and height and diameter were measured at the end of September 2015. Second year infiltration measurements indicated that both chemical treatments had significantly increased the infiltration capacity of the soil (P = 0.0003). Soil infiltration capacity on gypsum treated sites was about 55% higher than on sulfur sites. Following the second growing season, salt cedar had the highest survival rates of 80%. Silver poplar had 36% survival rates across the treatments. Russian olive had 50 cm height growth on both gypsum and sulfur application sites vs. only 25 cm on controls. Diameters of Russian olive on gypsum and sulfur sites were about 9.3 mm vs. 5 mm on the controls. Silver poplars on gypsum treated sites grew 42% taller than controls. Salt cedar had no significant growth responses among treatments. With appropriate soil amendments, especially gypsum, Russian olive gave the best overall two-year results.

• Yildiz, Düzce University, Faculty of Forestry, 81620 Duzce, Turkey E-mail: oktayyildiz@duzce.edu.tr
• Altundağ, Düzce University, Faculty of Arts and Sciences, 81620 Duzce, Turkey E-mail: ernazaltundag@duzce.edu.tr
• Çeti̇n, Düzce University, Faculty of Forestry, 81620 Duzce, Turkey E-mail: bilalcetin@duzce.edu.tr
• Guner, Eskişehir Soil and Ecological Research Institute, General Directorate of Forestry, 06560 Yenimahalle/Ankara, Turkey E-mail: stguner@ogm.gov.tr
• Sarginci, Düzce University, Faculty of Forestry, 81620 Duzce, Turkey E-mail: muratsarginci@duzce.edu.tr
• Toprak, Düzce University, Faculty of Forestry, 81620 Duzce, Turkey E-mail: bulenttoprak@duzce.edu.tr

This study evaluated the transformation of a Pinus tabuliformis Carrière forest into a near-natural forest after 60 years of natural development. The structure and soil characteristics of P. tabuliformis planted forest, the near-natural forest (coniferous-broadleaved P. tabuliformis mixed forest), and secondary forest (Quercus mongolica Fisch. ex Ledeb. forest) were compared. Tree, shrub and herb species diversity of the mixed and Q. mongolica forests was higher than that of the planted P. tabuliformis forest. Examination of soil characteristics revealed that compared to the pure pine forest, nitrogen (N) and phosphorus (P) concentrations of the mixed and Q. mongolica forests increased in the forest floor and soil, but total carbon (C) concentration decreased in the forest floor, countered by increases in the soil. Furthermore, soil cation exchange capacity (CEC) and pH in the P. tabuliformis forest increased when deciduous broadleaved species were present. Total microbial biomass and bacterial biomass in the soils were greatest in the Q. mongolica forest, followed by the mixed, and then the P. tabuliformis forests. However, fungal biomass did not significantly differ among the three forests. Overall, the findings of this study suggest that different forest types can affect soil microbial biomass and community structure. Meanwhile, the natural development is recommended as a potential management alternative to near-natural transformation of a P. tabuliformis planted forest.

• Chen, Department of Plant Biology & Ecology, College of Life Sciences, Nankai University, Weijin Road 94, Tianjin 300071, P.R. China E-mail: guopingchern@mail.nankai.edu.cn
• Shi, Graduate School of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8689, Japan E-mail: cshi1@for.agr.hokudai.ac.jp
• Cheng, School of Environment and Energy, Shenzhen Graduate School of Peking University, Shenzhen 518055, China E-mail: 1401213932@sz.pku.edu.cn
• Zhao, Baxian Mountain National Nature Reserve, Tianjin 301900, China Received 29 September 2016 Revised E-mail: zhaotiejiann456@sina.com
• Liu, Baxian Mountain National Nature Reserve, Tianjin 301900, China Received 29 September 2016 Revised E-mail: liuguoquan01@163.com
• Shi, Department of Plant Biology & Ecology, College of Life Sciences, Nankai University, Weijin Road 94, Tianjin 300071, P.R. China E-mail: fcshi@nankai.edu.cn

Silver birch (Betula pendula Roth.) is one of the main pioneer tree species occupying large areas of abandoned agricultural lands under natural succession in Estonia. We estimated aboveground biomass (AGB) dynamics during 17 growing seasons, and analysed soil nitrogen (N) and carbon (C) dynamics for 10 year period in a silver birch stand growing on former arable land. Main N fluxes were estimated and nitrogen budget for 10-year-old stand was compiled. The leafless AGB and stem mass of the stand at the age of 17-years were 94 and 76 Mg ha^–1 respectively. The current annual increment (CAI) of stemwood fluctuated, peaking at 10 Mg ha^–1 yr^–1 at the age of 15 years; the mean annual increment (MAI) fluctuated at around 4–5 Mg ha^–1. The annual leaf mass of the stand stabilised at around 3 Mg ha^–1 yr^–1. The stand density decreased from 11600 to 2700 trees ha^–1 in the 8- and 17-year-old stand, respectively. The largest fluxes in N budget were net nitrogen mineralization and gaseous N₂-N emission. The estimated fluxes of N₂O and N₂ were 0.12 and 83 kg ha^–1 yr^–1, respectively; N leaching was negligible. Nitrogen retranslocation from senescing leaves was approximately 45 kg ha^–1, N was mainly retranslocated into stembark. The N content in the upper 0–10 cm soil layer increased significantly (145 kg ha^–1) from 2004 to 2014; soil C content remained stable. Both the woody biomass dynamics and the N cycling of the stand witness the potential for bioenergetics of such ecosystems.

• Aosaar, Estonian University of Life Sciences, Institute of Forestry and Rural Engineering, Kreutzwaldi 1, 51014 Tartu, Estonia E-mail: jyrgen.aosaar@emu.ee
• Mander, University of Tartu, Institute of Ecology and Earth Sciences, Ülikooli 18, 50090 Tartu, Estonia E-mail: ulo.mander@ut.ee
• Varik, Estonian University of Life Sciences, Institute of Forestry and Rural Engineering, Kreutzwaldi 1, 51014 Tartu, Estonia E-mail: mats.varik@emu.ee
• Becker, Estonian University of Life Sciences, Institute of Forestry and Rural Engineering, Kreutzwaldi 1, 51014 Tartu, Estonia E-mail: hardo.becker@emu.ee
• Morozov, Estonian University of Life Sciences, Institute of Forestry and Rural Engineering, Kreutzwaldi 1, 51014 Tartu, Estonia E-mail: gunnar.morozov@emu.ee
• Maddison, University of Tartu, Institute of Ecology and Earth Sciences, Ülikooli 18, 50090 Tartu, Estonia E-mail: martin.maddison@ut.ee
• Uri, Estonian University of Life Sciences, Institute of Forestry and Rural Engineering, Kreutzwaldi 1, 51014 Tartu, Estonia E-mail: veiko.uri@emu.ee

There is evidence that moose are attracted to fertile growth habitats apparently due to better quality and larger quantities of food. The nutrients in mineral soils originate from the weathering of bedrock and the composition of parental bedrock affects the fertility of produced mineral soil, thus affecting also the import of nutrients into the whole food web. We surveyed the connection between moose damage in forest plantations and the composition of bedrock and surficial deposits in Finnish Lapland. We used a database of compensated moose damage in private forests in years 1997−2010. Undamaged stands in National Forest Inventories (NFI) from years 1986–2008 served as a control data and moose-damaged NFI-stands as a reference data. Bedrock and surficial depositions and the location of studied stands in relation to ancient shorelines were explored by using the digital databases of the Geological Survey of Finland. Moose-damaged stands were concentrated in southwestern and east Lapland in the areas of the Peräpohja Schist Belt and Lapland’s Greenstone Belt that are both composed of nutrient-rich rocks. The bedrock of damaged stands contained a higher proportion of mafic and alkaline rocks than did the control stands. Moose-damaged stands were pine-dominated and grew in more fertile forest sites than did control stands. Part of pine stands probably located in soils formerly occupied by spruce, which may increase the stands’ vulnerability to biotic threats. Especially, there were relatively more moose damage in pine plantations regenerated on fine-grained mineral soils derived from nutrient rich rocks than in less fertile soils.

• Ruuhola, Natural Resources Institute Finland (Luke), Natural Resources and Bioproduction, Yliopistokatu 6, FI-80101 Joensuu, Finland; University of Eastern Finland, Faculty of Science and Forestry, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: teija.ruuhola@uef.fi
• Nikula, Natural Resources Institute Finland (Luke), Economics and Society, Eteläranta 55, FI-96300 Rovaniemi, Finland E-mail: ari.nikula@luke.fi
• Vesa, Natural Resources Institute Finland (Luke), Economics and Society, Eteläranta 55, FI-96300 Rovaniemi, Finland E-mail: vesa.nivala@luke.fi
• Nevalainen, Natural Resources Institute Finland (Luke), Natural Resources and Bioproduction, Yliopistokatu 6, FI-80101 Joensuu, Finland E-mail: seppo.nevalainen@luke.fi
• Matala, Natural Resources Institute Finland (Luke), Natural Resources and Bioproduction, Yliopistokatu 6, FI-80101 Joensuu, Finland E-mail: juho.matala@luke.fi

Various environmental conditions (heat waves and drought events) strongly affect leaf and xylem phenology. Disentangling the influence of temperature, precipitation and soil moisture content (AWR) on the forest productivity remains an important research area. We analyzed the impact of climate variability on the leaf phenology (10 sample trees) and radial growth (17 sample trees) of European beech (Fagus sylvatica L.). The study was conducted on 130-year-old European beech trees growing in a temperate forest stand in the Czech Republic. Detailed 20-year phenological monitoring was performed at the study site (1992–2011). As expected, leaf phenological events were mainly driven by the growing season temperatures. Leaf unfolding was highly affected positively by spring temperatures and the top-layer (to 40 cm) AWR in March. The correlation of tree-ring width with the interpolated climate data was positive significant for the growing season AWR and precipitation signal. Furthermore, the water availability in the top soil layer was found to be an important predictor of tree growth and extremely low growth occurrence. The extended phenological growing season, which was caused by a temperature increase, was not followed by an increased tree-ring width. The examined relationships point out the significance of the water availability in the top soil layer in European beech stands.

• Kolář, Department of Wood Science, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 3, 613 00 Brno, Czech Republic; Global Change Research Institute, The Czech Academy of Sciences, Bělidla 986/4a, 603 00 Brno, Czech Republic E-mail: koldatom@gmail.com
• Giagli, Department of Wood Science, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 3, 613 00 Brno, Czech Republic E-mail: giagli@node.mendelu.cz
• Trnka, Global Change Research Institute, The Czech Academy of Sciences, Bělidla 986/4a, 603 00 Brno, Czech Republic; Department of Agrosystems and Bioclimatology, Faculty of Agronomy, Mendel University in Brno, Zemědělská 1, 613 00 Brno, Czech Republic E-mail: mirek_trnka@yahoo.com
• Bednářová, Institute of Forest Ecology, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědelská 3, 61300 Brno, Czech Republic E-mail: bednarov@mendelu.cz
• Vavrčík, Department of Wood Science, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 3, 613 00 Brno, Czech Republic E-mail: vavrcik@mendelu.cz
• Rybníček, Department of Wood Science, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 3, 613 00 Brno, Czech Republic; Global Change Research Institute, The Czech Academy of Sciences, Bělidla 986/4a, 603 00 Brno, Czech Republic E-mail: michalryb@post.cz

The occurrence of moose damage was studied using data from three National Forest Inventories (NFIs) accomplished between 1986 and 2008 in Finland. The combined data included a total of 97 390 young stands. The proportion of moose damage increased from 3.6% to 8.6% between the 8th NFI (1986–1994) and the 10th NFI (2004–2008). The majority (75%) of the damage occurred in Scots pine-dominated stands. The proportion of damage was higher in aspen-dominated stands than in stands dominated by any other tree species. The tree species mixture also had a clear effect on the occurrence of damage. Pure Scots pine stands had less damage than mixed Scots pine stands, and moose damage decreased linearly with the increasing proportion of Scots pine. Stands on mineral soil had more frequent moose damage than stands on peatlands. The fertility class of the site had no straightforward effect on the damage frequency. Artificially regenerated stands had more damage than naturally regenerated stands. Accomplished soil preparation measures and the need for thinning or clearing operations increased moose damage. High proportions of moose damage in young stands were found around the country. In the 10th NFI, the largest concentration of damage was found in southwestern Finland. Our study shows the temporal and spatial changes in the occurrence of moose damage and pinpoints some important silvicultural factors affecting the relative risk of young stands over a large geographical area.

• Nevalainen, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: seppo.nevalainen@luke.fi
• Matala, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: juho.matala@luke.fi
• Korhonen, Natural Resources Institute Finland (Luke), Economics and society, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: kari.t.korhonen@luke.fi
• Ihalainen, Natural Resources Institute Finland (Luke), Economics and society, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: antti.ihalainen@luke.fi
• Nikula, Natural Resources Institute Finland (Luke), Economics and society, P.O. Box 16, FI-96301 Rovaniemi, Finland E-mail: ari.nikula@luke.fi

Boreal forest soil contains significant amounts of organic carbon. Soil disturbance, caused for example by site preparation or stump extraction, may increase decomposition and thus lead to higher CO₂ emissions, contributing to global warming. The aim of this study was to quantify responses of soil-surface CO₂ fluxes (R_s) and litter (needle and root) decomposition rates following various kinds of soil disturbance commonly caused by mechanical site preparation and stump harvest. For this purpose four treatments were applied in a clear-cut site in central Sweden: i) removal of the humus layer and top 2 cm of mineral soil, ii) placement of a humus layer and 2 cm of mineral soil upside down on top of undisturbed soil, forming a double humus layer buried under mineral soil, iii) heavy mixing of the humus layer and mineral soil, and iv) no disturbance (control). R_s measurements were acquired with a portable respiration system during two growing seasons. To assess the treatments’ effects on litter decomposition rates, needles or coarse roots (Ø = 6 mm) were incubated in litterbags at positions they would be located after the treatments (buried, or on top of the soil). The results indicate that site preparation-simulating treatments have no effect or may significantly reduce, rather than increase, CO₂ emissions during the following two years. They also show that buried litter decomposes more rapidly than litter on the surface, but in other respects the treatments have little effect on litter decomposition rates.

• Mjöfors, Swedish University of Agricultural Sciences (SLU), Department of Soil and Environment, P.O. Box 7014, 150 07 Uppsala, Sweden E-mail: kristina.mjofors@slu.se
• Strömgren, Swedish University of Agricultural Sciences (SLU), Department of Soil and Environment, P.O. Box 7014, 150 07 Uppsala, Sweden E-mail: Monika.stromgren@slu.se
• Nohrstedt, Swedish University of Agricultural Sciences (SLU), Department of Soil and Environment, P.O. Box 7014, 150 07 Uppsala, Sweden E-mail: Hans-orjan.nohrstedt@slu.se
• Gärdenäs, Swedish University of Agricultural Sciences (SLU), Department of Soil and Environment, P.O. Box 7014, 150 07 Uppsala, Sweden E-mail: Annemieke.gardenas@slu.se