Articles containing the keyword 'nutrients'

The effects of fertilized treatment on the soil nutrient concentrations, biomass production and nutrient consumption of Salix x dasyclados and Salix ’Aquatica’ were studied in five experiments on three cut-away peatland sites in western and eastern Finland during three years. Factorial experiments with all combinations of N (100 kg ha^-1 a-¹⁾, P (30 kg ha^-1 a^-1) and K (80 kg ha^-1 a^-1) were conducted.

The application of P and K fertilizers increased the concentrations of corresponding extractable nutrients in the soil as well as in willow foliage. N-fertilization increased foliar nitrogen concentration. An increase in age usually led to decreases in bark and wood N, P and K concentrations and increases in bark Ca concentrations. N-fertilization increased the three-year biomass yield 1.5–2.7 times when compared to control plots. P-fertilization increased the yield only in those experimental fields whose substrates had the lowest phosphorus concentration. K-fertilization did not increase the yield in any of the experimental fields. The highest total biomass yield of NPK-fertilized willow after three growing seasons, 23 t ha^-1, was distributed in the following way: wood 42%, bark 19%, foliage 17%, stumps 6% and roots 16%. As the yield and stand age increased, more biomass was allocated in above-ground wood. Three-year-old stands (above-ground biomass 18 t ha^-1) contained as much as 196 kg N ha^-1, 26 kg P ha^-1, 101 kg K ha^-1, 74 kg Ca ha^-1 and 37 kg Mg ha ^-1. By far the highest proportion of nutrients accumulated in the foliage. The bark and wood contained relatively high proportions of calcium and phosphorus. With an increase in age and size, the amount of nitrogen and potassium bound in one dry-mass ton of willow biomass decreased while that of phosphorus remained unchanged.

• Hytönen, E-mail: jh@mm.unknown

Growth and nutrition of 20 clones representing different species and interspecific hybrids of willows (Salix spp.) growing on an abandoned field were studied. There were highly significant differences between the clones as regards the survival, number of sprouts per stool, sprout mean height and diameter and stem biomass production per stool. The differences between the clones in the concentration of all nutrients in both the leaves and stems were highly significant. 

• Viherä-Aarnio, E-mail: av@mm.unknown
• Saarsalmi, E-mail: as@mm.unknown

Spatial and age-related variation in nutrient concentrations of Scots pine (Pinus sylvestris L.) needles was studied during 1984–86 in three stands of different stages of development. The dry weight of current needles was significantly (p < 0.05) higher in the tree top than in a composite sample representing the whole crown. However, there were no significant differences in the concentrations of nutrients in needles between upper and lower crown levels. The concentrations of mobile nutrients N, P, K and Mg decreased with increasing needle age whereas the concentrations of poorly mobile nutrients Ca, Mn and Fe increased during needle ageing. The coefficient of variation for nutrient concentrations varied irregularly when only a few trees were sampled but stabilized when tree number was ten or more.
The PDF includes an abstract in Finnish.

• Helmisaari, E-mail: hh@mm.unknown

Effect of dolomite lime and wood ash (0, 0.5, 1, 2, 4, 8 and 16 kg m^-3) on the chemical composition of low humified Sphagnum peat was studied. Germination of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst.) and silver birch (Betula pendula Roth) and the subsequent growth of these seedlings were investigated in a greenhouse experiment. Nutrient concentrations in shoots and roots of pine seedlings were also analysed. The pH of peat increased asymptotically from 3.8 to about 7.0 with increasing lime regimen and to about 8.0 with increasing ash regimen. Wood ash linearly increased electrical conductivity and P, K, and Ca concentrations of peat. Rate of germination, within 7 days, of pine and spruce was best at low pH (<5) while birch seeds had a slightly higher pH optimum (4–6). Germination capacity, within 21 days, was not affected by pH or application regimen of either lime or ash. Pine and spruce seedlings grew best with lime and ash doses of 0.5–2.0 kg m^-3, the pH of peat being 4–5. Lime and ash treatments did not affect the growth of birch seedlings, but wood ash increased nutrient concentration of pine seedlings.

The PDF includes an abstract in Finnish.

• Rikala, E-mail: rr@mm.unknown
• Jozefek, E-mail: hj@mm.unknown

Refertilization with PK, about 15 years after the first fertilizer application, increased tree growth and the amount of nutrients in tree litter in Scots pine (Pinus sylvestris L.) and birch (mainly Betula pubescens Erhr.) stands on a drained fertile mire in Northern Finland (65°34 N’, 25°42’ E). The increase in growth and nutrient contents after refertilization was greatest in the mature pine stand where the application of nitrogen and micronutrients gave an additional response compared to the PK-application.

The PDF includes an abstract in Finnish.

• Paavilainen, E-mail: ep@mm.unknown

Quantitative variation in the elemental composition of living Scots pine needles was studied along an atmospheric pollutant gradient in the surroundings of the industrial town Harjavalta, south-western Finland. Two 9-km-long transects, each with nine sample plots, running to the S and SW from factory complex were delimited in a homogenous Scots pine (Pinus sylvestris L.) forest. Needle samples were taken from 10 trees at each site, and from two separate sites in Tuusula near Helsinki. There was considerable spatial variation in the elemental composition of the needles. Heavy metals (Cu, Fe, Zn) showed a clear pattern of exponentially decreasing concentration with increasing distance from the emission source. Sodium and potassium concentrations, as well as the ash weight and air-dry weight, also decreased. Magnesium, manganese and calcium concentrations increased with increasing distance.

The PDF includes an abstract in Finnish.

• Heliövaara, E-mail: kh@mm.unknown
• Väisänen, E-mail: rv@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 tolerance of disturbance of the ground and field layer vegetation in a moderately fertile Norway spruce (Picea abies (L.) H. Karst.) on Oxalis-Myrtillus type forest in Southern Finland was studied. One of the sites, a summer cottage yard had been raked regularly during the last 25 years. The structure of the vegetation was quite different compared to the other sample site situated in a virgin forest. The phytomass and percentual coverage of the vegetation was remarkable lower in the raked habitat. Tall mosses, Pleuroxium schreberi and Hylocomnium splendens had especially disappeared. Most grass shrubs had also deteriorated. Only Deschampsia flexuosa was quite tolerant to raking. The phytomass of the dwarf shrubs was lower in the raked area but their relative production was higher. Three different kinds strategies of species were described: species of virgin shaded forest, species of meadow-like forest floor and species which tolerate or benefit from disturbance. The raked habitat had a higher species diversity than the virgin area. Nitrogen and carbon contents were lower in the soil of the raked area.

The PDF includes a summary in Finnish.

• Lindholm, E-mail: tl@mm.unknown
• Nummelin, E-mail: mn@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 distribution of the dry matter and nutrients in Scots pine (Pinus sylvestris L.) tree stock growing on a Vaccinium type site, ground vegetation, and humus were determined in the study. The greatest part of the dry matter in the tree was found in the stemwood. The living branches, roots, bark, needles and dead branches decreasing order of magnitude made up the rest of the biomass. The trees contained over 90%, the field layer vegetation 3% and the bottom layer vegetation 2% of the dry matter in the tree stand. The tree stock contained 86–95% of the total amount nutrients in the stand. The field layer vegetation contained less nutrients than the bottom layer vegetation. Nitrogen, however, was an exception, the amount being approximately the same in both vegetation layers. 

The PDF includes a summary in English.

• Lehtonen, E-mail: il@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

The paper deals with the relationships between macronutrients, ground vegetation and tree crop on a drained peatland area in Central Finland. The former herb-rich spruce swamp was drained in 1930s. The Norway spruce (Picea abies (L.) H. Karst.) stand was established by planting under a nurse crop of birch, which was removed later.

There was a negative correlation between the thickness of the peat layer and the volume and mean height of the growing stock. This was found to depend on the negative correlation prevailing between the potassium content of the topmost peat layer and the thickness of the peat cover. The deficiency of potassium is clearly discernible as deficiency symptoms in the needles, the intensity of which showed a strong correlation with the stand characteristics studied. Among the nutrient characteristics of the topmost peat layer, total potassium and the N/K and P/K ratios showed the closest correlation with the stand characteristics. The communities into which the ground vegetation was divided differed from each other with regard to the calcium content of the peat substrate.

The PDF includes a summary in English.

• Mannerkoski, E-mail: hm@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

A theoretical framework to analyse the growth of Scots pine (Pinus sylvestris L.) is presented. Material exchange processes and internal processes that transport, transform and consume materials are identified as the components of growth. Hierarchical system is lined out. Momentary uptake of material at a single exchange site depends on the environmental condition next to the exchange site, the internal state of the biochemical system of the plant and the structure of the plant. The internal state depends on the exchange flows over period of time and the structural growth depends on the internal state. The response of these processes to the fluxes is controlled by the genetic composition of the plant.

The theoretical framework is formulated into a mathematical model. A concept of balanced internal state was applied to describe the poorly known internal processes. Internal substrate concentrations were assumed to remain constant but tissue-specific. A linear relationship between the quantity of foliage and wood cross-sectional area was assumed to describe balanced formation of structure. The exchange processes were thus described as a function of external conditions. The stand level interactions were derived from shading and effects of root density on nutrient uptake.

The approach was tested at different levels of hierarchy. Field measurements indicated that the hypothesis of the linear relationship described well the regularities between foliage and sapwood of a tree within a stand when measured at functionally corresponding height. There was considerable variation in the observed regularities in the range of geographic occurrence of Scots pine. Model simulations gave a realistic description of stand development in Southern Finland. The same model was also able to describe growth differences in Lapland after considering the effect of growing season length in the parameter values. Simulations to South Russia indicate stronger deviation from the observed patterns.

The simulations suggest interesting features of stand development. They indicate strong variability in the distribution of carbohydrates between tree parts during stand development. Internal circulation of nutrients and the reuse of the same transport structure by various needle generations had a strong influence on the simulation results.

The PDF includes a summary in Finnish.

• Nikinmaa, E-mail: en@mm.unknown

The first three-year effects of PK(MgB) and NPK(MgB) fertilization on the dry mass accumulation and nutrient cycling were studied in a Scots pine (Pinus sylvestris L.) stand growing on a drained low-shrub pine bog in Eastern Finland. The total dry mass of the tree stand before fertilization was 78 tn/ha, of which the above-ground compartments accounted for 69%. The annual above-ground dry mass production was 6.3 tn/ha, 51% of it accumulating in the tree stand.

The study period was too short for detecting any fertilization response in the stems. The total dry mass accumulation was not affected, because the increase in foliar and cone dry masses after both fertilization treatments, and that of the living branches after NPK fertilization, were compensated by the decrease in the dry mass of dead branches.

The nutrients studied accounted for 392 kg/ha (0.49%) of the total dry mass of the tree stand before fertilization. The amounts were as follows; N 173 kg/ha (44%), Ca 90 kg (23%), K 58 kg/ha (15%). The rest (18%) consisted of P, Mg, S and micronutrients combined. The unfertilized trees took up the following amounts of nutrients of the soil: N 15.6, Ca 12.8, K 4.1, P 1.3, MG 1.7, and S and Mn 1.5 kg/ha. The uptake of Fe and Zn was 510 and 130 g/ha and that of B and Cu less than 100 g/ha. More than 50% of the nutrient uptake, except for that of K and Fe, was released in litterfall. The results indicated very efficient cycling of K, Mn and B between the soil and trees.

The fertilized stands accumulated more N, P, K and B than the unfertilized ones during the tree-year study period. The increased accumulation corresponded to 35% (52 kg/ha) of the N applied on the NPK fertilized plots, 10% of the P, 25% of the K and 10% of the B on the PK and NPK fertilized plots. The increased amount of B released in litterfall after fertilization was equivalent to 4% of the applied B. Fertilization inhibited the uptake of Mn and Ca.

The PDF includes a summary in Finnish.

• Finér, E-mail: lf@mm.unknown

The purpose of this paper was to determine the proportions of nutrients remaining in the forest and removed from the forest as a result of cutting. The Norway spruce (Picea abies (L.) H. Karst.) phytomass remaining after clear cutting was studied in the categories of tree-top waste, branches, twigs, needles and cones. The bole wood, measured in solid cubic metres, was converted to kilogrammes on the basis of relative density determinations, and the amount of stump and root material estimated from the known amount of bole wood and comparable data presented in the literature. The nutrients studied were N (Kjeldahl), P (colour reaction), K, Ca, Mg, Fe and Mn (atomic absorption spectrophotometer). The wood and bark were studied separately. Details of the mineral composition of the bedrock are also presented.  

The harvested timber was found to account for 46 % of the total phytomass, or 58 % of the aerial phytomass, while the stump and root material represented one fifth of the total phytomass. The needles and bark contained the highest proportions of nutrients, especially in the case of nitrogen and phosphorus, the needles containing 32 % of total nitrogen and 26 % of total phosphorus. The surface waste wood contained on average more than double the amount of nutrients compared with the harvested bole wood, including more than six times the amount of phosphorus. Approximately one fifth of the nutrient contained in the total phytomass was removed on cutting. The high proportion of basic rocks in the area is suggested as an explanation of the nutrient status at the site, which is in many ways better than that described in the results of other investigations.  

The PDF includes a summary in Finnish. 

• Kubin, E-mail: ek@mm.unknown

The aim of the study was to assess the contents and quantities of macronutrients reaching the ground with precipitation, stemflow and throughfall in Scots pine (Pinus sylvestris L.) stands growing on drained peatland, one of which was unfertilized and two of which had been fertilized three growing seasons before the measurements were carried out.

According to the results, the quantities of nutrients reaching the ground with precipitation were relatively large as compared, for example, with those removed with the stem wood carried away from the forest in logging. The nutrient most exposed to leaching from the canopy is potassium. Both the content of potassium in rainwater penetrating the canopy and the quantities reaching the ground are highest in stemflow, decreasing when moving from under the tree crowns toward the edge of the crown projection and into openings in the canopy. The results for phosphorus were similar, although not as clear as for potassium.

The contents of NO₃-N were smaller in stemflow than in precipitation. The results did not support assumptions according to which nitrate nitrogen is leached from the canopy or is taken up by the canopy from precipitation. In the case both of precipitation and of throughfall and stemflow, the quantities of nitrite nitrogen recorded were smaller than the degree of precision applied in the determinations carried out (0.01 mg/1). The contents of NH₄-N were on average higher in stemflow and throughfall than in precipitation.

Fertilizer application (600 kg/ha of N-P₂O₅-K₂O, 14-18-10) increased the contents of potassium in stemflow and throughfall. A slight increase in phosphorus was also observed. Leaching of inorganic nitrogen was not affected by fertilization.

The PDF includes a summary in Finnish.

• Päivänen, E-mail: jp@mm.unknown

Novel information on silver birch (Betula pendula Roth) foliar element contents and their seasonal, between-habitat and leaf level variations are provided by applying fine-scaled element mapping with micro X-ray fluorescence. In the monthly leaf samples collected from May to October from six different habitats, pairwise scatter plots and Spearman’s rank correlations showed statistically significant positive correlations between Si, Al and Fe, and covariations between also many other pairs of elements. Of the ten elements studied, seven showed statistically significant changes in their average levels between May and June. The contents of P, S and K decreased in most habitats during the later season, whereas Ca and in some habitats also Mn and Zn increased. Comparing habitats, trees in the limestone habitat had relatively low content of Mg, strongly increasing levels of P until the late season, and high content of Ca and Fe. Other habitats also revealed distinctive particularities in their foliar elements, such as a high relative content of S and a low content of Ca at the seashore. Mn was high in three habitats, possibly due to bedrock characteristics. Except for P, the contents of all elements diverged between the midrib and other leaf areas. Zn content was particularly high in the leaf veins. Mn levels were highest at the leaf margins, indicating a possible sequestration mechanism for this potentially harmful element. Si may help to alleviate the metallic toxicities of Al and Fe. Because the growing season studied was dry, some trees developed symptoms of drought stress. The injured leaf parts had reduced levels of P, S and K, suggesting translocation of these nutrients before permanent damage.

• Kalliola, Department of geography and geology, University of Turku, FI-20014 Turku, Finland https://orcid.org/0000-0003-2454-8217 E-mail: risto.kalliola@utu.fi
• Saarinen, Department of geography and geology, University of Turku, FI-20014 Turku, Finland E-mail: tijusa@utu.fi
• Tanski, Department of geography and geology, University of Turku, FI-20014 Turku, Finland E-mail: niko.tanski@utu.fi

Picea abies seedlings were given three different fertilization treatments in the nutrient solution by varying the potassium:nitrogen (K:N) ratios (2.5, 3.0 or 3.9 g g^–1). All fertilization treatments were combined with short-day (SD) treatment or no such treatment (control). Above- and belowground growth responses in the seedlings were analyzed. The SD treatment resulted in significantly reduced shoot height, compared to untreated control, irrespective of K:N ratio. No combination of photoperiod treatment or fertilization treatment affected the root collar diameter. In the current year root fraction with diameter < 0.5 mm, the highest K:N ratio led to significantly increased root length in control plants. In each 0.1 mm root diameter class up to 0.5 mm, the highest K:N ratio significantly stimulated root growth in control plants, while the effect was less evident for SD plants. SD treatment stimulated length growth in some fine root diameter classes. We conclude that SD treatment is a good and sufficient measure to reduce height growth without compromising fine root growth of P. abies seedlings. Fertilization treatment did not significantly improve aboveground growth in SD treated seedlings, and only limited effects on root growth was seen on control plants.

• Fløistad, Norwegian Institute of Bioeconomy Research (NIBIO), P.O. Box 115, NO-1431 Ås, Norway E-mail: inger.floistad@nibio.no
• Eldhuset, Norwegian Institute of Bioeconomy Research (NIBIO), P.O. Box 115, NO-1431 Ås, Norway E-mail: toril.eldhuset@nibio.no

The long-term effects of fertilization on the needle nutrient concentrations, growth and financial performance of a Scots pine (Pinus sylvestris L.) stand was examined in a thick-peated drained peatland forest located in Central Finland. At the trial establishment in 1985, the trees were suffering from P and K deficiencies, but their N status was good. The fertilizer treatments were Control, PK (rock phosphate + potassium chloride), ApaBio (apatite phosphorus + biotite) and wood ash, applied both with and without N and replicated six times. All treatments containing phosphorus and potassium increased foliar P and K concentrations above the deficiency limits up to the end of the study period of 26 years. The effect of the fertilization on stand volume growth of Scots pine was strong and continued still at the end of the study period. The trees on ApaBio and PK plots grew nearly two-fold and those on Ash plots over two-fold compared with the control plots. In a thinning made at the end of the study period the total logging removal on fertilized plots was 1.5–2.2 times greater and included more saw logs than on the control plots. Ash fertilizer treatment outperformed other fertilizer treatments as well as the control. With a 5% discounted equivalent annual income (EAI) of Ash fertilizer treatment was statistically significantly (p=0.009) almost three times higher than that of control. As a conclusion, fertilization (either using PK fertilizers or Ash) in N-rich drained peatlands is a financially feasible method of management.

• Moilanen, Natural Resources Institute Finland, Natural resources and bioproduction, Paavo Havaksen tie 3, FI-90014 Oulu, Finland E-mail: mikko.moilanen@luke.fi
• Hytönen, Natural Resources Institute Finland, Natural resources and bioproduction, Silmäjärventie 2, FI-69100 Kannus, Finland E-mail: jyrki.hytonen@luke.fi
• Hökkä, Natural Resources Institute Finland, Natural resources and bioproduction, Eteläranta 55, FI-96301 Rovaniemi, Finland E-mail: hannu.hokka@luke.fi
• Ahtikoski, Natural Resources Institute Finland, Natural resources and bioproduction, Paavo Havaksen tie 3, FI-90014 Oulu, Finland E-mail: anssi.ahtikoski@luke.fi

• Tullus, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia E-mail: arvo.tullus@ut.ee
• Sellin, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia E-mail: arne.sellin@ut.ee
• Kupper, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia E-mail: priit.kupper@ut.ee
• Lutter, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi 5, Tartu 51014, Estonia E-mail: reimo.lutter@emu.ee
• Pärn, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi 5, Tartu 51014, Estonia E-mail: linnar.parn@emu.ee
• Jasinska, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia & Institute of Dendrology, Polish Academy of Sciences, Parkowa 5, 62-035 Kórnik, Poland E-mail: jasiak9@wp.pl
• Alber, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia E-mail: meeli.alber@ut.ee
• Kukk, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia E-mail: maarja.kukk@ut.ee
• Tullus, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi 5, Tartu 51014, Estonia E-mail: tea.tullus@emu.ee
• Tullus, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi 5, Tartu 51014, Estonia E-mail: hardi.tullus@emu.ee
• Lõhmus, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia E-mail: krista.lohmus@ut.ee
• Sõber, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia E-mail: anu.sober@ut.ee

• Martín-García, Sustainable Forest Management Research Institute, University of Valladolid – INIA, Avenida de Madrid 57, 34004 Palencia, Spain, and Forestry Engineering, University of Extremadura, Plasencia, Spain E-mail: jorgemg@pvs.uva.es
• Espiga, Sustainable Forest Management Research Institute, University of Valladolid – INIA, Palencia, Spain E-mail: ee@nn.es
• Pando, Statistics and Operations Research Department, University of Valladolid, Spain E-mail: vp@nn.es
• Diez, Sustainable Forest Management Research Institute, University of Valladolid – INIA, Palencia, Spain E-mail: jjd@nn.es

• Laiho, University of Helsinki, Department of Forest Ecology, FI-00014 University of Helsinki, Finland E-mail: raija.laiho@helsinki.fi
• Sarkkola, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: ss@nn.fi
• Kaunisto, Finnish Forest Research Institute, Parkano Research Unit, Kaironiementie 54, FI-39700 Parkano, Finland E-mail: sk@nn.fi
• Laine, Finnish Forest Research Institute, Parkano Research Unit, Kaironiementie 54, FI-39700 Parkano, Finland E-mail: jl@nn.fi
• Minkkinen, University of Helsinki, Department of Forest Ecology, FI-00014 University of Helsinki, Finland E-mail: km@nn.fi

• Veijalainen, Finnish Forest Research Institute, FI-77600 Suonenjoki, Finland E-mail: amv@nn.fi
• Juntunen, Finnish Forest Research Institute, FI-77600 Suonenjoki, Finland E-mail: mlj@nn.fi
• Lilja, Finnish Forest Research Institute, PO Box 18, FI-01301 Vantaa, Finland E-mail: al@nn.fi
• Heinonen-Tanski, Univ. of Kuopio, Dept. of Environm. Sc., PO Box 1627, FI-70211 Kuopio, Finland E-mail: hht@nn.fi
• Tervo, Finnish Forest Research Institute, FI-77600 Suonenjoki, Finland E-mail: lt@nn.fi

• Lapointe, Université de Sherbrooke, Département de biologie, 2500 boulevard de l’Université, Sherbrooke, QC, Canada J1K 2R1 E-mail: bl@nn.ca
• Bradley, Université de Sherbrooke, Département de biologie, 2500 boulevard de l’Université, Sherbrooke, QC, Canada J1K 2R1 E-mail: robert.bradley@usherbrooke.ca
• Parsons, Université de Sherbrooke, Département de biologie, 2500 boulevard de l’Université, Sherbrooke, QC, Canada J1K 2R1 E-mail: wp@nn.ca
• Brais, UQAT, 445 boulevard Université, Rouyn-Noranda, QC, Canada J9X 5E4 E-mail: sb@nn.ca

• Aphalo, University of Helsinki, Department of Biological and Environmental Sciences E-mail: pja@nn.fi
• Lahti, The Finnish Forest Research Institute E-mail: ml@nn.fi
• Lehto, University of Joensuu, Faculty of Forestry, Box 111, FI-80101 Joensuu, Finland E-mail: tarja.lehto@joensuu.fi
• Repo, The Finnish Forest Research Institute E-mail: tr@nn.fi
• Rummukainen, University of Joensuu, Faculty of Forestry, Box 111, FI-80101 Joensuu, Finland E-mail: ar@nn.fi
• Mannerkoski, University of Joensuu, Faculty of Forestry, Box 111, FI-80101 Joensuu, Finland E-mail: hm@nn.fi
• Finér, The Finnish Forest Research Institute E-mail: lf@nn.fi

• Laiho, Univ. of Helsinki, Dept. of Forest Ecology, Peatland Ecology Group, P.O. Box 27, FIN-00014 University of Helsinki, Finland E-mail: raija.laiho@helsinki.fi
• Penttilä, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland E-mail: tp@nn.fi
• Laine, Univ. of Helsinki, Dept. of Forest Ecology, Peatland Ecology Group, P.O. Box 27, FIN-00014 University of Helsinki, Finland E-mail: jl@nn.fi

• Hotanen, Finnish Forest Research Institute, Joensuu Research Centre, P.O.Box 68, FIN-80101 Joensuu, Finland E-mail: juha-pekka.hotanen@metla.fi

• Saarsalmi, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland E-mail: anna.saarsalmi@metla.fi
• Mälkönen, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland E-mail: em@nn.fi
• Piirainen, Finnish Forest Research Institute, Joensuu Research Station, P.O. Box 68, FIN-80101 Joensuu, Finland E-mail: sp@nn.fi

• Liu, Department of Forest Ecology, P.O. Box 27, FIN-00014 University of Helsinki, Finland E-mail: cliu@silvia.helsinki.fi
• Westman, Department of Forest Ecology, P.O. Box 27, FIN-00014 University of Helsinki, Finland E-mail: cjw@nn.fi
• Ilvesniemi, Department of Forest Ecology, P.O. Box 27, FIN-00014 University of Helsinki, Finland E-mail: hi@nn.fi