Acta Forestalia Fennica vol. 50 | 1942

The tree canopy adsorbs part of the rainfall falling on a forest, therefore only part of it reaches the soil. This report presents results concerning interception of precipitation and groundwater level in forests of varying canopy cover. The study belongs to a larger survey on afforestation of drained treeless bogs. The rainfall was measured daily in the open fields and in the adjacent forests. The forests, mainly Norway spruce (Picea abies (L.) Karst.) dominated, were divided by the canopy cover into five classes from over dense to sparsely stocked.

The results show that in a dense, tall Norway spruce stand, light rainfall can almost entirely be adsorbed by the canopy. The heavier the rainfall, the larger proportion of it reaches the ground. Only 30% of a 5 mm rainfall reaches the ground, while 80% of a 20 mm rainfall reaches the ground. Interception of precipitation decreases gradually when the density of the forest decreases. Canopy of Scots pine (Pinus sylvestris L.) and birch (Betula sp.) stands of corresponding density adsorb less rainfall than Norway spruce canopy. Groundwater level was higher in treeless areas than in areas covered with forest. Widescale clear cuttings should, therefore, be considered carefully in forest areas that are prone to become peaty.

• Lukkala, E-mail: ol@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

Effectiveness of 18 different saw blades of wooden bow saw from four producers (Oy Suomen Sandvik Sahat, Epilä Oy, Ab Orsa Sågbladsfabrik Oy, Kone ja Terä Oy) was tested in 1937. The experiments were divided into test series according to type of maintenance of the blade and tree species (Scots pine, Norway spruce and birch) to be sawn. Each saw blade was sharpened into four different sharpening angles (54°, 60°, 64°, 70°). Four blades had markedly longer sawing times compared to the others. These blades had a special serration. In addition, two blades with sparse serration had slightly poorer results than the blades in general. When the tree species were compared, birch (Betula sp.) was slowest to saw followed by Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.).

The PDF includes a summary in German.

• Aro, E-mail: pa@mm.unknown

The article is an overview of forest policy in the end of 1800s and beginning of 1900s in Finland. This is a period of time, when public opinion towards forest officers and forestry in the state forests was very critical. In 1870-1890 the discussion was also accelerated by language dispute between supporters of Finnish and Swedish in Finland. The root of the problem was in the middle of 1800s when management of state forests were gradually transferred to districts administered by forestry offices. At the same time, landless people had been settling in state-owned lands and establishing farms, mostly without permission. The questions concerning settling in state forests was often addressed to foresters in the forest offices. Several commissions discussed the situation, rights of the settlers and forestry in the state forests. The general opinion supported the settlers, and they were allowed to keep their farms. Towards the end of the century the value of state forests increased, which brought more emphasis on forestry in the state lands and restrictions to settlement. 

• Helander, E-mail: ah@mm.unknown

A time study was conducted in saw log harvesting site in state forests of Evo in Southern Finland in 1934. Felling was performed in teams of two loggers. Two teams were observed. The work was divided into several stages of work: felling, branching, cross-cutting, barking and making of top log. On the site grew Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.).

The daily working hours not including breaks was in average 5 hours and 33 minutes. The most time-consuming stage of the work was barking of the stem (55% of working time for Scots pine and 47% for Norway spruce), followed by felling (22.5% for pine and 19.4% for spruce), branching (11.7% and 21.6%) and cross-cutting (11.3% and 11.8%). Temperature affects barking strongly. Scots pine is slower to bark than Norway spruce. Similarly, butt and middle logs are slower to bark than top logs. It took in average 79.02 min to process one solid m³ of timber with bark and 91.45 min without bark.

The PDF includes a summary in German.

• Seppänen, E-mail: vs@mm.unknown

Due to shortage of large logs, sawmill industry has been forced to buy also smaller logs, which also pulp industry uses as a raw material. Sawmills must be careful in the pricing of the logs, because profitability of sawing of timber depends on the size of the logs. These industries use different measures when they buy timber: pulp industry uses piled measure in meters, while saw logs are measured individually in cubic feet. The aim of the study was to develop sets of figures on technical cubic measure of a saw log and its relation to a piled cubic meter from the same log used as pulp wood. In addition, the effect of form class on the measures was studied.

The relation was assessed for trunks that had good, mediocre or unfavourable form class, which distinction is easy to make for a forest worker buying timber. The relations can be used by a buyer of saw logs or pulpwood who need to compare the prices or when the seller of the wood compares the offers.

The PDF includes a summary in German.

• Wuoti, E-mail: ew@mm.unknown

The study is based on observations in a Scots pine (Pinus sylvestris L.) stand on a dry upland forest site in Karhumäki, where a 10-15-year old seedling stand grew under a hold-overs of larger trees that had been left in the site in a previous felling. The root systems of 80-120 cm tall seedlings growing around single mother trees were unearthed. Root maps were drawn of the root systems of 120 seedlings.

No seedlings grew around old, large hold-overs. It seems that seedlings could not compete with their root system. If the hold-overs were stunted in their growth, seedlings grew also under the canopy of the mother tree. 90% of the seedlings had a tap root. Rest of the roots grew horisontally in the topsoil. Around a vigorous mother tree, the seedlings grew their roots away from the mother tree. Hold-overs that had belonged originally to the lower canopy layer of the old forest did not have similar effect on the root orientation of the seedlings. Their roots had been previously affected by trees of higher canopy layer, later removed in the felling.

The PDF includes a summary in German.

• Kalela, E-mail: ek@mm.unknown

The article introduces methods that can be used to calculate economic profitability of draining of peatlands, and discusses their advantages and weaknesses. The time span from draining of a peatland and the future income is usually decades, which makes it difficult to assess profitability for the investment. For instance, income from future fellings depends on chosen rotation time, and price of timber that can fluctuate strongly.

When calculating the profitability, the drained area can be treated as a separate unit of account or as a part of the forest holding. In the first case, several methods can be used. First, yield in terms of value is a suitable method only if the peatland has no existing forest. Second, annual yield of a drained peatland and peatland in natural state can be compared. In this case yield can be defined in several ways. Third method uses value increment of the growing stock. Fourth method estimates value of increment for both the growing stock and land. Fifth method is based on present value of the future felling income, and sixth on actual value of the growing stock and yield in terms of value.

The PDF includes a summary in German.

• Saari, E-mail: es@mm.unknown

The article describes the adolescence and the birth of his interest in botany of well-known Finnish botanist, professor Johan Petter Norrlin, born in 1842, specialized in Hieracium species.

• Cajander, E-mail: ac@mm.unknown

Temperatures needed in extracting Scots pine (Pinus sylvestris L.) seeds is relatively high, however, there is little information on its effect on germination of the seeds. This survey aimed at studying how different temperatures affect both extraction result and germination of Scots pine seeds. Comparisons between different temperatures (20, 30, 40, 50, 60 and 70 ºC) were made from cones collected from same sample trees, three trees in total.

Temperatures 20 and 30 ºC resulted in incomplete opening of the cones, and gave thus smaller amount of seeds. Complete extraction requires at the least the temperature of 40 ºC. The result is slightly better in 50 ºC, but germination of the seeds is little lower. Temperatures 60 and 70 ºC improve the results, but in the cost of germination. The main reason for lower germination percentage was that the higher temperatures release more empty and defective seeds from the cones. Results of different sample trees were different due to, for instance, quality and size of cones. Higher temperatures accelerated the extraction. According to the study, perfect extraction in 40 ºC requires longer extraction time than when the temperature of 50 ºC is used. In practice, 50 ºC temperature or even little higher temperatures can be used when the extraction time is shorter. Decessive factors in choosing the temperature would be the humidity of cones and length of extraction time.

The PDF includes a summary in German.

• Kangas, E-mail: ek@mm.unknown

Walking in forests, hiking, is considered to be necessary for healt in many countries. In United States national parks cover 1.8% of total forest area. In addition, 25% of the forests are so called national forests, which have paths, campsites, wells, beaches, cottages etc. for hikers. In Finland, 20% of the population lives in towns and cities. Also in Finland the people living in cities and towns would need areas that resemble national forests of United states for recreation.

The PDF includes a summary in German.

• Vesterinen, E-mail: ev@mm.unknown

The article discusses the state of forest management of private forests and the need to awaken the forest owners for sustainable use of forests. According to the latest national forest inventory in Finland, only 15% of forests had good productivity, 50% had satisfactory and 35% low productivity. This is partly due to the forest owners’ insufficient knowledge on efficient forest management and the actual value of their forest. If the forest owners should have information of the wood resources of their forests in the level production, value and what kind of wood assortments it can in the future produce, there would be a pressure for more efficient forest management. The writer suggests that inventory of private forest holdings larger than, for instance, 25 hectares should be conducted in each municipality. The inventory could be performed in 10% of the forests each year. In this way the forests would be surveyed every 10 years. The information could also be used in taxation of forests. The best method to conduct the survey would be a line survey combined with circular sample plots.

The PDF includes a summary in German.

• Appelroth, E-mail: ea@mm.unknown

The article summarizes import and export of timber and manufactured wood products in Europe before the Second World War, and outlines which are the opportunities of import and export after the war. The evaluation is based on statistics of 1936 and 1937. The export balance of Europe was positive; when all the timber assortments were included, Europe exported almost 10 million m³ more timber than it imported. Export and import of round timber were almost in balance, whereas export of paper products was about 12 million m³ larger than import. Consequently, European forest industry reached its magnitude before the war through export overseas. Foreign markets have been important especially for countries like Finland and other Nordic countries.

The war has disturbed the markets. In a scenario where Europe remains a closed sub-area in the global market, there is 10 million m³ excess of timber and wood products. Within Europe, United Kingdom is the greatest importer of timber and manufactured wood products. If UK was excluded from the European market, it would mean a big change in the export and import balance within the area. In 1936 and 1937 the import would have been only 45% and 55%, respectively, of the export if UK is not included in European numbers. If also Russia is excluded from the European sub-area, it would affect especially the export of round wood, sawn timber and plywood. Nordic countries have accounted for about 80% of European paper products export before the war. According to the article, Finnish wood resources do not allow big increase in sawn industry. However, there is potential in increasing demand of pulp in continental Europe in future. In general, Finnish forest industry would have to decrease the production, if the markets would be limited to the European sub-area.

The PDF includes a summary in German.

• Pöntynen, E-mail: vp@mm.unknown

The article discusses use of felling value in determining the value of growing stock. It has been argued that use of felling value to calculate value for a forest holding usually leads to too high values. Consequently, when setting a price for growing stock, felling value should be applied only for such parts of the property that can be sold immediately at a current price.

The article describes in detail assessment of the felling value, first using timber assortments of the stand, and second, by conducting the felling value using parameters affecting the value, such as volume and tree species of the stand. An assessment method  was developed to calculate the value by using structure of a cubic metre of timber in a stand. The structure was determined using data of the national forest inventory in Finland. Finally, the article discusses application of the method.

The PDF includes a summary in German.

• Lihtonen, E-mail: vl@mm.unknown

The Second World War revealed some weaknesses that affect also peacetime planning of military defence in Finland. One of the shortages were lack of maps applicable in military purposes in Northern Finland.

The state forests are mainly situated in the north. Consequently, cartographic material of Finnish Forest Service may be modified with little extra work for military purposes. Best suited for the purpose are forestry maps of different forest districts that have scales ranging from 1:20,000 to 1:100,000. In addition, general maps in the scale of 1:100,000 or 1:200,000 are available. The article discusses further the additions that can be made in the maps.

The PDF includes a summary in German.

• Linnamies, E-mail: ol@mm.unknown

Of the foreign tree species Siberian larch (Larix sibirica Ledeb.) has the biggest economical potential in Finland. In its natural distribution the species grows mostly in mixed stands in other areas than the core of its range in Siberia, where it grows also in pure stands. However, growth studies have given contradictory results about how Siberian larch can manage competition of different tree species in mixed stands. In this study two-year old Siberian larch seedlings were planted in areas previously sown with Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.). The growth of the trees was measured when the stands were 50 years old.

It appears that the stands, about 3700 larch seedlings per hectare, have originally been too been too dense. In the two thinnings done in the area, larch has probably been favoured, which has resulted in varying mix of pine and spruce. In the 50-year old stands, Siberian larch has developed faster than Scots pine and Norway spruce. Contrary to some previous studies, the results show that Siberian larch can be grown also in mixed stands, but the growth will probably be slower than in pure stands. Best growth is achieved in pure stands that have been planted thinly enough.

The PDF includes a summary in German.

• Lappi-Seppälä, E-mail: ml@mm.unknown

Article presents some rare cone formations found from a small spruce in region of Punkaharju, Finland. In this case all the scales have developed into perfect, green needle leaves. Instead of a normal scale of a cone there are formations of buds that on the basal part of a cone resemble a normal bud, and hence develop into a branch. On the upper part of the cone formation the bud develops into scale of a cone.

The morphological form of the cones has been interpreted many ways. These anomalies resemble earlier observations and hence support the former theory of inflorescence. According the theory, the scales and scales of a cone are separate leaves, the scale corresponding to one leaf, the scale of a cone corresponding to two leaves. A cone is hence rather to be compared with a branching inflorescence than only one flower.

The PDF contains a summary in Finnish. 

• Kujala, E-mail: vk@mm.unknown

The aim of the study was to investigate effect of growth conditions on germination and growth of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) seedlings in greenhouse conditions. Germination of seeds becomes markedly slower as the soil temperature decreases. It seems that low temperatures affect more Norway spruce than Scots pine. When temperature rises, the fresh weight of the seedlings increases more in pine seedlings than in spruce seedlings. Accordingly, lower temperatures affect less the weight growth of spruce seedling than that of pine seedlings.

An experiment testing how root competition affect germination showed that adjacent seedlings decrease germination of seeds more than shading with branches. The effect was strongest on pine and spruce seedlings when the shading tree species was fast growing birch (Betula sp.). On the other hand, shading affected most height growth of birch seedlings. Growing space can vary in relatively large range without it affecting greatly tree growth.

The PDF includes a summary in German.

• Aaltonen, E-mail: va@mm.unknown

The dependence of elastic and tensile properties of coniferous trees on the share of summer wood can be presented as linear functions, if the soft wood is considered as a statically indefinite structure. By eliminating the share of summer wood by a certain function presented in the article, the elastic and tensile properties are the linear functions of density.

The functions are proved right by conducting strength tests on pine. Practical implications of the derived functions in rating the quality of wood are also presented.

The PDF contains a summary in Finnish. 

• Ylinen, E-mail: ay@mm.unknown

Finnish municipalities can be classed in towns and cities, market town and rural communes. In 1942 there was 27 market towns in Finland. The aim of this study was to investigate the amount and state of forests in market towns. The data was collected mainly by interviewing the authorities of the market towns in 1936-1938. The statistics about forests were often insufficient.

The total land area owned by market towns was 8,963 ha, 71.7% of which was forest land, 12.0% wasteland and 16.3% arable land. A total of 21 of the 27 market towns own forest. Of all the land owned by the market towns about half is situated within borders of the town, however, 57% of the forest land is situated outside the market town itself. The forest areas are small, only four towns own more than 500 ha of forests, and only six has a forest management plan. The silvicultural state of the forests seems, however to be relatively good.

The PDF includes a summary in German.

• Rautvuori, E-mail: er@mm.unknown

Birches’ (Betula sp.) ability to grow sprouts is low. The stump grows root collar and stump shoots, but the stump shoots are not proper stump shoots that will grow from the space between wood and bark. The buds are situated very low in the base, even under the ground. In this study, no actual root shoots could be found. Also the bushy alpine birches seem to be formed from stump and root collar shoots.

In Southern Finland silver birch (Betula pendula Roth) is more common than downy birch (Betula pubescens Ehrh.) in dry upland forest sites, while downy birch is common in fresh mineral soil forests and peatlands. In Northern Finland downy birch is the dominant birch species. Of the two species downy birch has markedly better capacity to form stump and root collar shoots both in Northern and Southern Finland. In general, birches grow sprouts much more strongly in Northern Finland.

Growth of the shoots is fastest during the first year after the felling of the parent tree and slows down gradually. The stump shoots may get separated from the stump when the stump decays, and the decay may also spread to the shoots. It is common that the shoots have no own roots, and die along with the stump. The shoots may have own root system or use roots of the parent tree that have stayed alive, in the latter case decay spreads almost always from the stump to the shoot. Whether the tree was felled with axe or saw had no effect on sprouting, probably because the sprouting buds are situated in the base of the tree. The larger stumps had usually fewer sprouts than smaller stumps. The fertility of the site seemed to have little effect on sprouting, but more moist sites formed more sprouts.

Forest regeneration using sprouts may be possible in peatlands for firewood production. on mineral soil sites birch does not suit for coppicing. The proportion of trees originating from sprouts decreases strongly by the time. Consequently, in Southern Finland sprouts have little effect on regeneration of birch. In Northern Finland sprouting is the most important way of regeneration.

The PDF includes a summary in German.

• Mikola, E-mail: pm@mm.unknown

According to the 1st national forest inventory of Finland, municipalities owned 178,000 hectares of forests in 1922, about 0.7% of the total forest area of the country. Only 60,000 hectares of these belonged to urban municipalities. The amount had increased to 73,000 hectares by 1938. Although the area was small, forests were important for municipal economy. The aim of this study was to investigate the state and forest management practices of forests in urban municipalities. The data was collected mainly by interviewing the authorities of the municipalities in 1936-1938.

Forests covered 50-80% of the area of the urban municipalities, the total area varying from 111 hectares to 7,791 hectares. Only four municipalities owned more than 5,000 hectares of forests. Annual profit of forestry in all urban municipalities totalled about 4.6 million Finnish marks in 1931-1935. Quality of productive forest lands was relatively good, but the volume and growth of the forests rather low. The silvicultural state of the forests could be improved. The article points out that this requires continuous planning. The basis of this is forest management plan, which has been demanded of municipal forests since 1893. However, some of the urban municipalities still lacked a forest management plan, or it was not fully used in forest management.

The PDF includes a summary in German.

• Linnamies, E-mail: ol@mm.unknown
• Rautvuori, E-mail: er@mm.unknown

The aim of the study was to find out what are the causes of damage in Scots pine (Pinus sylvestris L.) stands and the frequency of different kinds of injuries, which are then discussed in relation to the silvicultural state and management of the stands in comparison to ideal forests. Sample plots were studied in over 80-year old Scots pine dominated stands in mineral soil sites of different forest types in Northern Finland in the area of Perä-Pohjola. 10–40 trees were chosen as sample trees in each sample plot. The sample trees were felled, and the diameter, height of crown and injuries outside and inside of the stem were recorded.

Length of knot-free part of the stem was higher in the dominant trees and in older age classes of the trees. The form of the stem becomes broader and rounder with the age. The crowns are, however, longer in Northern Finland compared to Southern Finland. In management of Scots pine stands, all trees diseased by Scots pine blister rust (Cronartium flaccidum) should be removed. The disease is common in Northern Finland, and the number of diseased trees increases as the stands get older. Decay was more common in trees that had fire wounds. In general, injuries decreased the length and diameter growth of the trees. From the dominant trees should only injured and diseased trees removed in the thinnigs. Codominant trees can be left to grow when spare trees are needed to replace missing dominant trees. Detailed instruction of selection of the removed trees are given for each age class.

The PDF includes a summary in German.

• Tikka, E-mail: pt@mm.unknown