Acta Forestalia Fennica vol. 75 | 1963

The forest management practices in Finland are closely related to the industrial history in the country. The selection cutting method used previously has now been gradually disappearing, and differences in the quality of forest management can still be observed between different owner groups. The national forest inventories indicate that farm woodlots show the poorest silvicultural state among the ownership categories. This study analyses social and economic causes responsible for variation in the silvicultural state of farm woodlots managed jointly with a cultivated land holding. The study is based on the data of third national forest inventory in Finland, and a factor analysis was calculated using the data.

Although the model developed explains more than a half of the total variance of the level of silviculture, only less than third of this is clearly explained by economic and social factors. The remaining two thirds are explained by the ’nature factor’, which includes both economic and site factors. This affects the effect of different kinds of forest policy measures. Of the variables in the model, the strongest influence in the level of silviculture have income, size of woodlot, size of land area under cultivation and distribution of forest types. The differences in the level of silviculture between different woodlots and different districts, may be explained by the theory of cumulative process. Regional differences in economic phenomena cannot be explained without taking into consideration the social value hierarchy in each region, which determines the range of variation of economic variables.

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• Riihinen, E-mail: pr@mm.unknown

The purpose of this study was to analyse economic models used in certain studies and to evaluate whether the economic theory envisaged by a model is consistent with its aims in forest policy. Second, the paper will point out assumed improvements for models that can be used as a basis for forest policy.

There are two types of economic models according to their purpose. One type, the marketing models, can be used for explaining or forecasting the consumer’s behaviour with no intension to affect the economies to be gained from the alternative patterns of behaviour explained. Others, the policy models, are meant to serve as guideposts which by means of normative forecasts point out the programme to be followed in order to attain certain aims. The majority of the policy models are static. The paper assesses the static models, and evaluates how well they fit their purpose. Special attention is given to dynamic economic models. A dynamic model can, at least in principle, be used to explain the course of events during the adjustment period required to achieve a production goal.

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• Riihinen, E-mail: pr@mm.unknown

The objective of this study has been to discover some of the basic principles on which an increment for a large forest area might be forecast. Because the stands in a large forest area vary considerably in density and are subject to different kinds of treatment, the main interest falls on the stand characteristics which determine the increment percentage in such forest conditions as these. The material used in the study has been published earlier, it consisted of sample plots of Scots pine (Pinus sylvestris L.) stands (Nyyssönen 1954).

Increment functions are of great importance in the increment forecast for cutting budget. Because 60-80% of the variation in the increment percentage can be explained by stand characteristics in circumstances where the age of the stand is 40-130 years and the volume vary with a coefficient of variation 0.6-0.7, regression equations for increment percentage may be based on a number of sample plots smaller than in a growing stock inventory in the same conditions. It is possible to get accurate results with relatively small number of sample plots. Furthermore, the smaller amount of increment sample plots makes it possible to develop measurement techniques.

The increment functions enable study of increment as a biological process. However, conclusions about biological process on the basis of regression equations should be made with caution. Still, regression analysis is a powerful tool in yield studies.

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• Kuusela, E-mail: kk@mm.unknown
• Kilkki, E-mail: pk@mm.unknown

In Finland roundwood is floated either privately or co-operatively. In the later, a co-operative floating association is established to operate floating. The association is compulsory association of those enterprises who want to have wood floated along the floating routes of the area. It is favoured when the number of enterprises and the wood to be floated is large. In addition, costs are lower than in private floating.

Floating in Lake Saimaa area in Central Finland can be divided into Iso-Saimaa, where floating is private, and into Saimaa Water System, where floating is operated by a co-operative floating association. It has been suggested that adoption of co-operative floating in Iso-Saimaa would be to the common interest. This study aimed at finding out if co-operative floating influences the transport costs, and if co-operative floating increases competition of roundwood by forest industry companies.

According to the study, the costs of most enterprises would decrease. The total decrease in costs would amount to 65 million Finnish marks annually, about 20% less than the present costs. The change of organization would not alter the competitive relationship in buying roundwood. On the other hand, it would seem that co-operative floating would be less flexible than private floating. The management of a large organization, whose effective operation time would cover only a part of the year, would meet with some difficulties. Also, co-operative floating would reduce competition among enterprises.

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• Roitto, E-mail: yr@mm.unknown

It is necessary to study the problems related to the size, number and location of sample plots as well as to the effect of stratification. This paper, mainly concerned with the volume of the growing stock based on measurements, comprises a part of the research in progress related to the issue.

The study contains a discussion of certain problems relevant to the planning of a forest inventory on the basis of variation in the volume of the growing stock. In particular, the aim has been to give data for selection of the size and number of sample plots, and to illustrate the importance of stratification, here based principally on dominant height.

The research material comprised two forest areas of 10 ha each; measurement of the growing stock was made in units of 49 m². Based on the data was constructed a model area embracing 4 forested strata and one non-forested stratum. The mean and standard deviations of the volumes was calculated for the forest area as a whole and for the different strata. On studying stratification, two approaches were employed to distribute the sample plots among the strata: optimum allocation and proportional allocation. The latter is simple in application, and gave for forested areas number of sample plots which did not exceed by more than 10% those obtained by optimum allocation. It is obvious that the application of stratification is worthy of consideration within forest areas which comprise parts with distinct differences. The decrease in number of plots with increasing plot size is considerably more marked within a stratified area. Thus, larger sample plots should be used in the former case than in the later. The investigations give hints on how forest inventories should be carried out. However, it has some limitations, which are discussed in the paper.

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• Nyyssönen, E-mail: an@mm.unknown
• Vuokila, E-mail: yv@mm.unknown

This paper aims at studying regeneration of Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.) by sowing and natural regeneration of birch (Betula sp.) in Western Finland.

Germination of spruce and pine seeds may be prevented by dryness and temperatures below the optimum for germination. In natural conditions, when temperature and moisture is insufficient for germination, the type of seedbed generally has en effect on germination result. Trenching of the seeding spots showed that root competition during the early stage of regeneration was not of decissive importance. It seemed to, however, improve the preservation of the seedlings later. It is common that it can take long before the seeds germinate, and during that time the number of viable seeds decrease strongly.

Also, the seedling stock quickly began to decrease in number after germination, especially during the first growing season and the following winter. The decrease was larger in intact vegetation than on mineral soil or in the humus layer. The emerging seedlings were destroyed by drought very easily, but their tolerance to drought improved later on.

The PDF includes a summary in English.

• Yli-Vakkuri, E-mail: py@mm.unknown