Acta Forestalia Fennica vol. 74 | 1962
Category : Article
Short run market forecasting is desirable both for adjusting production and for regulating the national employment policy. In this study a forecast is made for one product. The purpose of the study is to develop a short run model describing newsprint sales in Finland that will combine mathematical simplicity, accuracy of description and universality.
Two methods of selecting variables seemed to be available. According to the first, newsprint consumption is divided into components, each of which is considered separately. The second method, which proved more fruitful, starts out directly from factors influencing the publishers’ decisions in purchasing newsprint, eliminating the least significant intuitively and simultaneously determining the lags.
The models developed in this study are capable of forecasting potential consumption. Even the best models in this study are multicollinear. The further into the future a forecast is extended, the greater is the possibility that relationships between the explanatory variables will change. It is intended that the newsprint seller will profit from the models achieved by using them to forecast sales in a future period, so that he can avoid both loss of interest due to acquiring a surplus of raw material or acute shortages of raw material.
The PDF includes a summary in Finnish.
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Riihinen,
E-mail:
pr@mm.unknown
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.
The PDF includes a summary in English.
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Kuusela,
E-mail:
kk@mm.unknown
- Nyyssönen, E-mail: an@mm.unknown
The aim of the study is to find out 1) whether and how the original moor type can be found out based on vegetation regardless the phase of drainage; 2) whether the different phases of draining can be distinguished based on the vegetation; and 3) is it possible to classify the well drained moors into vegetation types that would reflect the productive capacity of the land.
The data consists of samples collected from ditched areas. There are 11 moor types from two climatic ditching zones. The results show that the original moor type can be determined based on vegetation, the phase of drainage can be determined under some limitations, and the classification for productivity can be done for practical purposes.
The PDF contains a summary in Finnish.
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Sarasto,
E-mail:
js@mm.unknown
Two lines can be defined in the management planning for the State Forests of Finland: 1) general planning for regions and inspectional sub-regions based on forest inventory, and 2) management plans for individual districts based on the revision of each district after 10–15 years. Long-term planning is has recently been alleviated by several new methods, such as stock-development forecast and yield tables.
A stock-development forecast and cutting budget were prepared separately for each State Forest region. The present growing stock was based on the data collected in the inventory in 1951–1955. Desirable stock for each region was calculated. The methods to calculate total cut during near future, allowable cut, allowable cut by timber products, the long-term development of the allowable cut, and conditions for realizing the allowable cut are presented in the paper.
The development of the growing stock towards a desirable condition requires also realization of a silvicultural program. Because the Finnish forest industry is expanding vigorously, the amount of the allowable cut on a sustained basis must be estimated carefully. Otherwise the demand for wood may exceed the supply. Though there are many sources of error in preparing a long-term cutting budget, it was considered necessary for State Forestry. An approximate estimate of the largest cut on a sustained basis and a program of silvicultural measures necessary to increase the yield gradually has been worked out.
The PDF includes a summary in English.
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Linnamies,
E-mail:
ol@mm.unknown
In this paper the development of sown Scots pine (Pinus sylvestris L.) seedling stands into forests is studied. The material was collected in stands sown in 1930–1940 in private forests in the Forestry Board districts of Central and Northern Ostrobothnia. The 119 areas, including both burned and other areas, were studied in 1955.
Most seedings had been carried out on relatively poor soils, mostly representing Vaccinium and Calluna type forests. 71% of the areas consisted of large forest fires, mostly from 1933. The most burned areas did not have seed producing trees nearby. The other sown areas were in general small, 1–2 ha, and near forests capable of producing seeds. The species of previous tree generation, in the older areas mostly pine and in the younger areas Norway spruce, affected tree species composition of the new tree generation.
Over 90% of the burned areas were in silviculturally good or satisfactory condition, while the main part of the other sown stands was in fair or poor condition. Weeding and thinning had been done only in the oldest stands. Most stands had been left untended. Natural new trees often competed with the sown pines, and cull-trees and border forest increased natural regeneration in the areas. In Calluna type the poor soil limited regeneration and growth of broadleaf trees. The worst competitors were naturally regenerated pine seedlings both on Calluna and Vaccinium type. On Vaccinium type also birch and sometimes also aspen (Populus tremula L.) competed with sown pine. On better sites and paludified areas competition by broadleaf trees increased. The rhythm of development of broadleaved trees is so different from pine that only those broadleaved trees that are formed in the stand when the pine seedlings are larger can develop harmoniously with pine. Due to the harmful competition, the seedling stands should be tended early on. In addition, it may be advisable to abandon the practise to leave trees on sowing areas.
The PDF includes a summary in Finnish.
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Yli-Vakkuri,
E-mail:
py@mm.unknown
The size of the field and the ditching on it as well as the condition of the field at the time of the surrender of Porkkala area (from Finland to Russia) play an important role on how far the natural regeneration of the fields has progressed.
Larger open fields have naturally regenerated only on sides where the surrounding forest can spread the seeds or the thicket of saplings has reached, whereas small parcels of fields have normally been fully forested. Most important species have been e.g. silver birch and pubescent birch, grey and common alders and European aspen as well as pine and spruce. The broad leaved species are dominant.
The PDF contains a summary in Finnish.
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Kalela,
E-mail:
ek@mm.unknown
Prescribed burning has been used in regeneration areas in Finland as a method to treat the humus layer and creating more favourable chemical, physical and biological conditions for the seedlings. At the same time, fire clears away seedlings and shoots of unwanted trees and other vegetation. Direct sowing or planting, mostly Scots pine (Pinus sylvestris L.), seldom natural regeneration, is used. In this paper, the initial stages of the formation of a new tree generation of Scots pine and Norway spruce (Picea abies (L.) Karst.) on prescribed burned areas is studied in Central Finland in 1956–1960.
The burned area remains almost without vegetation for about two growing seasons. Conditions on a burned area which has not been tiled are very unfavourable for germination of seeds of coniferous and deciduous trees. On the other hand, shoots of deciduous trees occur soon after burning. Conditions for regeneration were found to be better 3–5 years after burning. Removal of humus layer in spots improved regeneration. However, the patches facilitated also natural regeneration of Norway spruce and especially birch (Betula sp.), which compete with Scots pine seedlings.
Continuous rainy periods improved the germination of Scots pine and Norway spruce seeds sown on the humus layer. Pine and spruce developed more rapidly on the exposed soil, however, young seedlings were easily destroyed. Seed eaters destroyed the pine and spruce seeds sown on the humus layer of newly burned areas completely or almost completely. The viability of pine seeds sown on the burned humus layer did not decrease for three weeks, but the viability greatly weakened after six or more weeks. Spruce seeds lost their viability faster than pine seeds.
The PDF includes a summary in Finnish.
-
Yli-Vakkuri,
E-mail:
py@mm.unknown
