Current issue: 58(5)
Because the ‘rental cut method’ is rather arduous and based partly on subjective analysis, new forms for a cutting budget has been developed. One of them is a method called stock development forecast, and another method will be described in this paper. The main characteristics of the present growing stock affecting the allowable cut are the forest area, site quality, forest composition by age and development classes, volume, and increment.
In the method described in this paper an analysis of the desirable stock is necessary. The allowable cut is a function of the current and desirable stock and the increment during the budget period. The budget is based on information about the forest area, site quality, growing stock and its structure, collected from an inventory. The desirable stock is described in the same sub-groups as is the current stock. An increment forecast is prepared by compound and an interest formulae and increment percentages are presented as a function of the stock age. The allowable cut shows the average amount of the cut during the management plan period.
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An estimate of value of a forest holding is needed, for instance, when the holding is sold. There is, however, no standard method for forest valuation. This paper describes a method based on yield in terms of value that is estimated on the basis of cutting budget. The first, mensurational part of the investigation concentrates on calculation of cutting budget that can be used in forest valuation. Second part studies how chronological order of fellings changes allowable cut in forests that differ by age-class distribution and other structural properties. Structure and variation in the structure of silviculturally different forests are determined for the forests that form the data for the investigation.
According to the study, even if the forests studied in the investigation included forests which structure differed in their age-class distribution from normal forests, they could be managed in a such way that in 5-6 decades the age-class distribution resemble that of a normal forest, and have growing stock that correspond the stock of forests in Southern Finland, about 80-110 m3/ha. Based on this, the cutting budgets of the later decades of the first rotation can be assumed to be nearly even. The original age-class distribution of the forest affects, however, allowable cut of the forests during the first decade. The revenues of the first decade have small impact on the value, the later decades strong. Consequently, development of the most valuable part of the allowable cut, timber trees, has big impact on the value. The results show that in young forests the planned cut including the proportion of timber trees increases, in middle-aged forest it is relatively even, and in old forest declining. The results indicate the order of magnitude the planned cut can be in near future in diferent kinds of forests, and when different felling regimes are used to reach different goals.
The PDF includes a summary in German.
The purpose of this study was to clarify increment forecast methods in connection with the cutting budget. The emphasis is laid on the Finnish increment per cent methods. A tentative attempt is made to carry out a passage calculation. Increment forecasts are accomplished for diameter class distribution of a 60 years old Scots pine (Pinus sylvestris L.) stand. The increment data for the growing stock are taken from the domestic increment calculating tables.
When comparing the results of the two methods, the increment values are expressed in rabatt per cent in which the forecasted annual increment is in proportion to the initial value of the growing stock. It will be emphasized that the weak point in the domestic budgets is in the relation between the increment of the developable stock and the increment of the exploitable stock. Almost all the Finnish increment data are from the developable trees and the estimates of the increment of the exploitable trees have not been on sufficient facts.
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The aim of the study was to develop a method for calculating a cutting budget that is adapted to the present forest management practices. The cutting budget determines the volume of annual cuttings for a forest holding in a certain period of time. Effect of fellings on the cutting budget depends on the cutting methods used. The study aimed at proving that growth of the forest can be estimated based on growing stock and structure of the forests for a certain time period. Accordingly, adequate drain can be defined in advance. The cutting budget is based on age-class distribution of the forest holding, which is most applicable for even-aged forestry. Calculation is based on area of the forest land and estimated volume of the growing stock. Also, the quality of the forest soil can be taken into account when age-class distribution is used. A suitable period for estimating a cutting budget is suggested to be 20 years, which is divided in two 10-year periods. The cutting budget it is included in a forestry plan. An example of a cutting plan based on the method is presented.
The PDF includes a summary in German.
The paper is the final report of a study on the estimation of value increment and inherent variables of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) stands. The main aim was to obtain improved criteria for decision-making concerning the priority of stands for regeneration.
The construction of various estimation models and their reliability are discussed in detail. The study, together with some previous papers, has resulted in a system which on the basis of a number of easily assessed stand variables gives for the stands concerned the volume of stems, percentages of timber assortments, stumpage value, volume increment and value increment.
The following examples are given with regard to the practical application of the results, in addition to the determination of the relative maturity of stands: 1) The study of various trends in stand development; the comparison between the volume and value variables. 2) The estimation of timber assortments needed for a cutting budget, trees marked for felling etc. 3) The calculation of the value of forests.
The PDF includes a summary in English.