Articles containing the keyword 'metsikkö'

The concepts of the terms compartment and compartment-wise forest inventory have been studied empirically by repeated delineation and intensive systematic plot samples. The material consisted of 16 study areas of some 8–90 hectares in size in Southern Finland and of more than 1,000 relascope plots. Stands and compartments were found to be rather heterogenous. Alternative photographs, working techniques and test persons were studied. An endeavour for better accuracy in compartment inventories is recommended.

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• Poso, E-mail: sp@mm.unknown

Dependence of the growth increase given by fertilization on different stand characteristics is examined in this article. The aim was to determine whether the volume growth increase can be accurately determined beforehand when fertilization is carried out on mineral soil sites at a dosage of 120 kg N/ha. The material consisted mostly on of mature stands ready for cutting, a total of 22 Scots pine (Pinus sylvestris L.) and 20 Norway spruce (Picea abies (L.) H. Karst.) stands. Increase in basal area, height quality class and basal area of the stand were found to best explain the increment and its increase in the regression equations calculated for different types of fertilizer and the control level.

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• Jokinen, E-mail: rj@mm.unknown

The study is part of a project designed to elucidate the nutrient budget of a Scots pine (Pinus sylvestris L.) stand. Results of variation in the nutrient contents were compared with those obtained for the previous growing season.

The potassium and calcium contents varied the greatest in the humus layer. However, in the bottom and field layer vegetation and needles the variation in the nitrogen content was the greatest. The nutrient contents of the needles were affected by the physiological stage of development, needle age and the position in the crown of the tree. The nutrient content of the rainfall increased in the order: free rainfall, throughfall, and stem flow.

The PDF includes a summary in Finnish.

• Lehtonen, E-mail: il@mm.unknown

This study forms part of a project designed to elucidate the total nutrient budget of a Scots pine (Pinus sylvestris L.) stand in Central Finland during the 1974 growing period. Precipitation has been divided up into precipitation, throughfall and stemflow.

The acidity of the rainwater was found to increase in the order – Precipitation, throughfall and stemflow. The electrolyte content of the rain water from throughfall and stemflow was higher than that of precipitation. The nutrient contents of precipitation were rather low. Throughfall and stemflow were found to leach some nutrient from the trees. This was most clear in the case of potassium. The total amounts of nutrients reaching the ground in throughfall were found to be smaller than those in precipitation. On the other hand, the amounts of potassium, calcium and magnesium in stemflow were clearly greater than those in precipitation.

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

The aim of the paper was to study the amount and distribution of rainfall in a virgin Norway spruce (Picea abies (L.) H. Karst.) stand. Special attention has been paid to the dependence of throughfall on the characteristics of the precipitation falling on an open area and the stand.

The throughfall was 62% of the precipitation in the open. The best independent variable as regards the throughfall was the amount of precipitation falling in the open. The heaviness of precipitation in the open gave no meaningful correlation. Horizontal layout of the stand was found to have some effect on the throughfall. The throughfall was also influenced by the tree species composition of the stand. Only 52% of the total variance of the amount of water caught by the rain gauges could be predicted with the characteristics of the precipitation in the open and the stand.

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• Kellomäki, E-mail: sk@mm.unknown
• Pohjapelto, E-mail: pp@mm.unknown

The purpose of the study was to measure the throughfall in a managed Scots pine (Pinus sylvestris L.) stand in Southern Finland (61°47’, 24°18’). Totally 20 summer rain gauges (collecting area 100 cm²) were placed randomly in form of a lattice of 100 squares, each 2x2 m. Six rain throughs, 15 cm x 150 cm, were placed in the experimental stand. Auxiliary precipitation measurement was done in an opening, by using four summer rain gauges, two rain throughs and one recording rain gauge. The throughfall was followed in May–September 1967.

In comparison with summer rain gauges, the rain throughs gave too low values when the precipitation was below 3 mm/rain shower. Accordingly, only the results of rain gauges were used. The rate of throughfall was determined by the amount of precipitation and the rate of heaviness of the rain shower. When trying to describe the relative amount of throughfall by using various characteristics of the stand, the equitation proposed by Seppänen (1964) proved the best. When the rate of throughfall was depicted with the distance between the summer gauge and the nearest tree, there was negative correlation between these. The correlation was negative under heavy rains, but positive in small rains.

Various factors of uncertainty are discussed. During long periods the areas under Scots pine canopies reach more rain water than those between the canopies, which may be important when analysing the spatial distribution of ground vegetation.

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• Leikola, E-mail: ml@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.

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• Saari, E-mail: es@mm.unknown

An explorative study on wind conditions in a well-managed Scots pine (Pinus sylvestris L.) stand was made in Southern Finland. The wind velocity was recorded continually with two cup anomometers from April to August, 1964. The two levels used were 2 m and 9 m. The wind velocity was lower at 2 m than within the canopy at 9 m. The dependence on the absolute wind velocity at 9 metres was logarithmic. The wind velocity did affect the difference between daily minimum temperatures at the two levels; the difference in the maximum temperatures was affected only in May and August.

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• Leikola, E-mail: ml@mm.unknown

Stand precipitation and stemflow studies became necessary in connection with hydrologic studies, for instance, to explain the deviations resulting from rains in the ratios between the water content of peat and the groundwater level, throughfall during rains of variable heaviness, and effect of stand treatment on soil moisture level. In this project the distribution of rainfall in stands differing in species composition and density was studied in Central Finland in 1963–1965 in fifteen stand precipitation sample plots. In addition, rain gauges were situated under individual Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst.) and birch (Betula sp.) trees.

The average precipitation in the open was 4.8 mm, the corresponding precipitation in the stand was 77% for birch, 71% for pine and 62% for spruce. Measurements of stemflow from individual sample trees showed that less than ¼ mm (about 1.5%) during a 15 mm rain in a pine stand. In the spruce stands stemflow is negligible. A part of the sample plots was in drained peatlands with a dense vegetation of small shrubs. The shrub layer retention was about 10% even during heavy rain. In a small forest clearing, the bordering effect of the forest was seen up to the distance of 5 metres from the edge of the forest. During the period of study, on an average 3% more precipitation was recorded in the clearing than in the open, the difference being probably due to the stronger wind effect in the open.

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• Päivänen, E-mail: jp@mm.unknown

The present study proposes to calculate the economic sequence of two of Finland’s three main tree species, Norway spruce (Picea abies (L.) H. Karst.) and silver birch (Betula pendula Roth) when planted on Oxalias-Myrtillus type sites where both species are equally suitable, on biological grounds. In addition, the accuracy and applicability of the present Finnish yield tables to an economic comparison is tested. Benefit/cost ratio was selected as criterion of profitableness. All future net incomes and costs were discounted into the planting time and added together. The ratio between the discounted net revenues and the discounted investment costs (later called profit ratio) was the criterion. There is no reliable method to forecast the future wood prices, therefore two price ratios, birch veneer timber to spruce pulpwood and birch cordwood to spruce pulpwood, were chosen as free variables. The economic sequence of the tree species was determined as the function of these variables.

The main conclusions are, first, that under the present price ratios spruce appears to be the better choice for the forest owner, and the most promising policy for changing the situation seems to decrease the production costs of plants in birch nurseries. Second, the present Finnish yield tables are not consistent or accurate enough to enable any sufficiently reliable economic comparisons of tree species in artificial regeneration. The possible error of difference between two rather uncertain estimates is big. More work is needed to construct a uniform system of yield tables covering all main tree species, all site types, all macro climate conditions and all types of regeneration.

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• Keltikangas, E-mail: mk@mm.unknown
• Tiililä, E-mail: pt@mm.unknown

Distribution of rainfall in in a Scots pine (Pinus sylvestris L.) stand and in an open place in Alajärvi in Central Finland was studies in 1959–1960. Density of the about 80 years old stand was 0.36 and the height of the trees 8–14 m. The dependence of throughfall and dependence of stemflow on 24-hour precipitation, and dependence of the distribution of 24-hour precipitation on the amount and nature of precipitation was calculated.

The precipitation of the crown of the forest depended on the rainfall. When the rainfall in the open place was over 7 mm, the rainfall within the forest was in average 89% of the rainfall in the open place, but if the rainfall in the open place was less than 1 mm, the rainfall within the forest was only 64% of that in the open place. Total stemflow in the pine stand was only 0.4%, and interception loss was 13.6%.

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• Seppänen, E-mail: ms@mm.unknown

Draining transforms root systems of trees growing in peatlands towards the ones growing on mineral soil. However, even after efficient draining the root systems differ from the root systems of trees growing on mineral soil. This investigation concentrates on root systems of forests of similar mire types growing in similar draining conditions but having different tree species compositions. The peatland, situated in Pieksämäki in Southern Finland, was drained in 1937. Sample plots, measured in 1956, consisted of mixed forest of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies L. Karst.) and birch (Betula sp.) in different compositions, and were in natural condition.

The sedge pine bog studied in this investigation was shown to have larger total amount of roots and mycorrhiza than in previously studied dwarf shrub pine bogs. This reflects better growth conditions of the better site. The depth of root system was, however, similar. Root systems of birch were deeper than those of the coniferous tree species. Differences between Scots pine and Norway spruce were small. Corresponding differences between the species were found in the density and total number of mycorrhizas. The abundance of mycorrhizas in the roots of birch increased in deeper layers of peat, but decreased especially in spruce roots. In earlier studies the abundance of mycorrhizas decreased in the roots growing in deeper layers in pure Scots pine stands, but no such variation was seen in this study. The result suggest that the deep root system of birch may affect also the root systems of the coniferous trees. On the other hand, birch roots can have advantage over the coniferous trees.

The PDF includes a summary in German.

• Heikurainen, E-mail: lh@mm.unknown

The purpose of this study was that of providing a long-term timber production model (Kilkki and Pökkälä 1975) with growing stock models. The paper is divided into two parts; the first is concerned with generation of the stand data through Monte-Carlo simulation. The growing stock of each stand was described by a DBH-height distribution. The necessary information on the relationships between the stand characteristics was derived from sample plots measured in the national forest inventory of Finland. A total of 1,500 Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst), and birch (Betula sp.) stands, each comprising 100 trees were provided by simulation.

In the second part, models predicting the form factor, timber assortment distribution, and value of the growing stock were derived through regression analysis for each species of tree. The predicting variables included the form factor of the basal area median tree, basal area median diameter, and height in the form factor models. In the timber assortment and value models, the only predicting variable was the volume of the basal area median tree. The Matchcurve-technique (Jensen 1973) was employed in derivation of the regression models.

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• Kilkki, E-mail: pk@mm.unknown
• Siitonen, E-mail: ms@mm.unknown