Articles by Kullervo Kuusela

Europe’s forest area has increased 5 million ha since the late 1960s. The growing stock has increased 43% and the net annual increment 55% in exploitable forests since 1950. A part of the reported increase is caused by sampling inventories, which have been made in greater part of the countries. Sampling inventories have corrected earlier underestimates of the growing stock and the increment.

The difference between the annual net increment and fellings has increased since 1950. The net increment, 584 million m³, exceeded fellings, 408 million m³, by 176 million m³, in exploitable forests in 1990. If fellings could be increased to equal the increment, Europe would be an exporter of forest products.

A greater increase in the density, in the age and in the mean volume of forests per hectare threaten the biological stability of the growing stock. Degrading of the stock, increasing natural losses and deteriorating environmental qualities of forests can only be prevented by increased fellings and by forest regeneration.

The PDF includes an abstract in Finnish.

• Kuusela, E-mail: kk@mm.unknown

Forest balance is a comparison between the growing stock volume at the beginning and end of a balance period and the gross increment and drain during that period. The forest balance of Finland during that period 1967-1973 and the increment and drain balance during the period 1953-1977 are used as examples in the paper. Forest balance is a check of the accuracy of basic estimates. If the discrepancy between the calculated growing stock at the end of the balance period and the growing stock estimated by an inventory is great, it calls for improvements in forest inventory methods and timber utilization statistics.

Balance may reveal possibilities for improving the utilization of forest resources. If natural losses are great, increased thinnings and regeneration cuttings of mature and over-mature tree stands increase the supply of timber. If logging losses are great, the efficiency of harvesting should be improved. An overcutting situation calls forth efforts to increase timber production or to decrease the uses of timber in order to avoid overexploitation. If gross increment is greater than the drain there are possibilities to increase harvesting, forest industrial expansion etc.

Forest balance is a way to check and improve the basic estimates of forestry production, to increase the effective use of timber grown in the forest, to commerce policies and measures concerning increment and to control timber utilization on the basis of sustained yield.

The PDF includes a summary in Finnish.

• Kuusela, E-mail: kk@mm.unknown

Pair numbers of breeding land birds were estimated from line transects data collected in Finland in 1936–76. The changes observed in the bird populations are in this paper compared with data obtained in the Finnish forest inventories, particularly made in 1951–53 and 1971–76. It is concluded that modern forestry has considerable impact on the breeding bird fauna. In general, more species have increased than decreased due to changes in the forests. Areas affected by forestry are more favourable habitats for many species than natural forests, but, on the other hand, there are certain species which are greatly harmed by the effects of modern forestry.

The PDF includes a summary in English.

• Järvinen, E-mail: oj@mm.unknown
• Kuusela, E-mail: kk@mm.unknown
• Väisänen, E-mail: rv@mm.unknown

The Economic Council asked Heikinheimo, Holopainen and Kuusela to prepare a report on the development of Finland’s forest resources up to the beginning of the next century. The expansion of forest industry beyond the level foreseen in earlier forecasts, the large-scale removal and neglect of the basic improvements required have weakened the condition of the wood production to such an extent that extensive measures are needed to ensure the continuity of the supply of wood. The results of the calculations are formed in three separately analysed alternatives.

Alternative I: Realisation of the Teho programme and the removal corresponding to it. The development of the growing stock according to the programme would only permit a cut amounting to an annual drain of ca. 51 million m³ up to the year 2000. After that it would be possible gradually to increase the removal. This drain would not itself to utilise fully the already existing production capacity of the industry.

Alternative II: Consequences of the predicted removal if the Teho programme is realised as such. The wood utilization forecast based on the premises given to the team show that the annual drain will grow in 1964–1975 from 52 to 58 million m³, and thereafter by 0.5% annually. This would lead to over-cutting, and exhaust the present growing stock by the turn of the century. If annual total drain of ca. 58 million m³ would after 1975 be sufficient, exhaustion of the growing stock would be postponed for 4–5 years.

Alternative III. Teho programme expanded in conformity with the removal forecast. A new programme is proposed, which includes, among others, large scale fertilization of fully grown firm forest land at about the rate of 100,000 ha/year, intensified artificial regeneration, assurance of the supply of planting stock and seed, increase of forest drainage from the present 155,000 to 250,000 ha/year by 1970, site preparation of the cutting areas for artificial regeneration, increase of tending or seeding stands to 300,000 ha/year, replacement of fuelwood by other fuels, increase of wood import and new forest roads.

• Ervasti, E-mail: se@mm.unknown
• Heikinheimo, E-mail: lh@mm.unknown
• Holopainen, E-mail: vh@mm.unknown
• Kuusela, E-mail: kk@mm.unknown
• Sirén, E-mail: gs@mm.unknown

The agricultural committee appointed by the Finnish Government in 1958 pointed out a problem that the rural population needed to be ensured employment and earnings from forestry. A forestry study group was called to investigate the effects of forest improvement on employment and income, on four fields: a) forest drainage, b) afforestation, c) thinning of young stands, and d) construction of forest roads. Items a, b and c increase output, and d creates outlets for timber and increases stumpage value.

The study outlined three alternative silvicultural programmes. The Basic Programme corresponds average forest management in Finland in 1953–1959. The Medium Programme can be seen conditional to the realization of the felling plan worked out in a study group Heikurainen-Kuusela-Linnamies-Nyysönen in 1961 in a committee report of Forestry Planning Committee. Finally, according to an Intensive Programme to which forest management, especially afforestation and forest drainage, will be raised to the highest possible level.

The costs of different silvicultural measures of the three programmes were estimated. The allowable cuts were calculated corresponding to the silvicultural programmes for the period 1961–1970 and 2001–2010. After calculating labour input and costs, could the increase in employment and income be estimated for the whole economy, and separately in forestry, communications and industry. When calculating the labour input required for the forest management work and road construction, the probable rise in productivity following mechanization and rationalization has been taken into account.

The PDF includes a summary in English.

• Heikinheimo, E-mail: lh@mm.unknown
• Heikurainen, E-mail: lh@mm.unknown
• Holopainen, E-mail: vh@mm.unknown
• Keltikangas, E-mail: mk@mm.unknown
• Kuusela, E-mail: kk@mm.unknown
• Möttölä, E-mail: tm@mm.unknown

• Kuusela, E-mail: kk@mm.unknown
• Setälä, E-mail: ks@mm.unknown

The study is continuation of the earlier structure and growth studies of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) in Forest Research Institute. The material represents birch stands (Betula verrucosa, now B. pendula, and B. Pubescens L.) in Southern Finland. The stands were treated with different fellings, and in regard to their silvicultural condition classified as good, satisfactory and unsatisfactory. Height of the trees, height of living crown, volume, increment and volume increment and development of stem diameter series was measured.

The most characteristic difference between the silviculturally good and poor stands was that the the annual increment of the good stands concentrated into large size trees, and the increment of unsatisfactory stands into small and inferior trees.

It is concluded that if the aim of stand treatment is to produce large and high quality volume increment, the most favourable stand volume of  birch stands, compared with naturally normal stand volume, seems to be 90-85% at the age of 41-55 years, and 80-70% at the age of 56-65 years. If growth of large size trees is aimed at, the maximum number of the dominant trees per hectares cannot be more than 400 at the age of 50-60 years.

The article includes a summary in English.

• Kuusela, E-mail: kk@mm.unknown

After the Second World War Finnish Forest Service was faced with large e-mapping and timber surveying project in Northern Finland. The funds for mapping were very limited. In order to re-map the large areas, the only way was to look for alternative methods for the ground methods. The photogrammetric equipment of Finnish Army was made available to the civil service. Consequently, since 1947 several forest mapping projects were carried out in co-operation between the Forest Service and the Army Topographic Service.

When more funds were coming available for the project, new instruments were acquired. The article describes the present mapping procedure and suggests alternative ways in procedure and utilization of new equipment. It concludes that if the forest area under modern timber management plans is several million acres, the ideal implemental framework for mapping and timber surveying unit in Finland should be the following: Radial Secator RS I and slotted templates for the radial line plot, Stereotope Plotter for drafting general maps, the old Delft Scanning Stereoscope for photo interpretation, and Aero-Sketchmaster for transport of the photo details.

• Kuusela, E-mail: kk@mm.unknown

The most important fact to consider in attempting to develop an increment forecast method is the great dependency of the increment on the growing stock volume. Although the site (soil and climate) produces the increment and volume, there would be no increment without the volume as an increment capital. The cutting possibilities are still more dependent on the existing growing stock. Thus, the primary characteristics in management planning is the growing stock volume. The methodological starting point in this paper is that the increment is considered dependent variable which can be explained by other growing stock characteristics. The basis of the analysis and the primary object of this investigation is the increment percentage. Using available and measured sample plots the increment percentage will be analysed as a dependent variable by other growing stock characteristics.

The main emphasis will be the methods which can be used in connection with the interacting increment and drain. An increment-drain forecast should give at least approximately the allowable cut in timber products. Thus, it will be attempted to find the stock characteristics determining the amounts of timber products.

The article introduces the theory and basic concepts of the increment-drain process, increment functions and basal area – height method, and discusses estimation of timber products in increment-drain forecast, fluctuations of the increment, mortality in connection with the increment-drain forecast, and the scheme of cutting budget for desirable growing stock. Finally, it gives some proposals, based on the investigation, for preparing an increment-drain forecast for a large forest area.

The PDF includes a summary in Finnish.

• Kuusela, E-mail: kk@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.

The PDF includes a summary in Finnish.

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

• Kuusela, E-mail: kk@mm.unknown
• Nyyssönen, E-mail: an@mm.unknown

The annual fellings and sales of pulpwood from the State Forests of Finland comprised 4.0–4.6 million m³ in 1955–1959. In order to improve the accuracy of the methods used in estimating the pulpwood stocks marked for felling, a pilot survey of 18 marked stocks was carried out in 1959. The stock area, average plot volume, variation of the plot volumes, size and shape of the plot and the distribution of the trees by diameter classes as factors affecting the precision have been studied in this paper.

The greater the mean volume of a plot the more homogenous is the structure of the marked stock. The same number of plots gives a better relative precision for the south Finnish marked stock than for the north Finnish ones, which are heterogenous and less valuable. Stocks smaller than 50 ha can often be estimated more advantageously by the strip method or visually than by the plot method. The proper size of plot in Southern Finland is 0.02–0.03 ha. In Northern Finland the plots should be larger due to the heterogenous stocks, about 0.05 ha. The shape can be either circular or rectangular. The former may be more practical and reliable in the field. The minimum number of sample trees is considered to be about 200 per 100 sample plots 0.03 ha in size.

The PDF includes a summary in English.

• Kuusela, E-mail: kk@mm.unknown

The purpose of the investigation was to study the characteristics of the site and the growing stock and the effect of their variation on the precision of forest inventory. The total area of the forest tract is considered to be already known or it can be measured with surveying. The sub-areas or strata and the mean timber volume of each wooded stratum are estimated by sampling. Thus, the total volume of each stratum is the product of the estimates of the area and mean volume. Only line method of sampling the areas will be examined. Field material was measured in the inventory of the Finnish State Forests with the method used in the third National Forest Inventory. The circular plots and the sample trees were measured in the forests of Inari district. In this systematic line-plot method the distance between the lines was 5 km.

The results show that the total area should be broken down into suitable strata, such as the full-stocked productive forest land and regeneration areas with mother trees. The mean volume for each stratum is estimated with the plot method. An advanced estimation of the approximate mean volume and the coefficient of variation in the strata are needed for calculating the optimum allocation of plots.

If the volume calculation is done with the diameter as variable the variation of the plot volumes is decreased. If the local volume table is used and the site and stock characteristics differ from the characteristics of the volume table stock, a significant systematic error is possible. Planning of efficient and economical forest inventories requires data concerning site and stock variation. It should be calculated and published systematically by geographical region.

The PDF includes a summary in English.

• Kuusela, E-mail: kk@mm.unknown

The relascope method, introduced by Bitterlich, has been mostly used in estimating the basal area of tree stands or growing stock. Volume estimation requires, in addition, mean height and form. The purpose of this study is to work out a method for calculating the volume, bark and increment of the stand from the measurements of sample trees taken on a plot determined with the relascope. All trees of the same diameter have their own plot size and the stand characteristics are the sum of all tree characteristics multiplied by a blow-up factor which is a function of the diameter.

Accurate determination of a sample plot with the relascope requires checking the boundary trees with a tape. In an average forest there are 10 to 20 unit trees on each plot if the opening of the relascope is 2 cm. Because all trees of equal diameter to be tallied on a sample plot represent an equal share of the total basal area, the number of trees to be tallied is very economical from the stand point of volume estimation. Objective selection of the sample trees can easily be done. The unit volume per hectare represented by each tallied tree, or by each sample tree, is directly proportional to the tree height. Thus, the estimates of the stock characteristics can be calculated as arithmetic means from the sample tree characteristics. The calculation procedure which gives the ordinary stock table, volume, bark and increment is also easily carried out with punched cards.

The PDF includes a summary in Finnish.

• Kuusela, E-mail: kk@mm.unknown

The purpose of the investigation was to study the factors which determine the amount of the largest permanent allowable cut and to work out a method to estimate it. There is a need to have a ’short cut’ formula for rough preliminary estimates. The preliminary estimates will be checked by stock development forecasts. The largest allowable cut and its sustained basis are only guaranteed by a forecast through a period during which all the present tree stands have reached maturity and exploited.

Estimations of the largest permanent allowable cut are based on the data of the present and desirable growing stock. The present stock was a growing stock of Scots pine (Pinus sylvestris L.) dominated stands on Vaccinium type forests in Southern Finland. The connected Austrian formula is a simple way for preliminary estimation of the largest cut but its sustained basis must be checked by a stock development forecast.

In a stock development forecast the future increment and cut are calculated. For this purpose, the average site quality, tree species, age class and average volume in each class seem to be sufficient variables. The forecast is carried out within the limiting data of the present and desirable stock.

If there is an abundance of mature and over-mature stands, the largest permanent allowable cut is greater than the present increment, provided, however, that bulk of the cut is drawn by determined generation measures. Measured in solid cubic meters, the sustained cut from the Southern Finnish pine stock exceeds the present increment by 11%. With regard to the sustained saw timber production the cut can exceed the present increment by 5–7%.

The PDF includes a summary in English.

• Kuusela, E-mail: kk@mm.unknown

An investigation was carried out in the area of Beas River in India in the conifer forests of the region to study the possible supply of raw material for forest industries. The investigation based on an agreement between the Government of Finland and the Government of India about techcnical assistance to India.

The results of the survey suggest that though the Himalayan conifer forests are scattered and they lie on high altitude and in difficult terrain, their potential value is very important to the Indian national economy. Their extraction is feasible in much larger scale than now. The present yield coming to the markets is 30-10%, or even less, of the obtainable yield under intensive management and integrated utilization of wood. The obtainable yield could support comparatively large saw milling as well as pulp and paper industries.

The problems in developing the Himalayan conifer forestry cover the field of forest management, silviculture, re-forestation, logging, relations between forestry and the local population, forest administration, sales policy and industrial planning. Estimating the actual possibilities requires reliable resource inventories. Cultivation of trees for primitive sleeper production should be abandoned, management systems modified in accordance with the principle of progressive yield. The future management should be based on the exploitation of the existing over-mature stock and on the growth of the new stands.

The PDF includes a summary in Finnish.

• Kuusela, E-mail: kk@mm.unknown

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.

The PDF includes a summary in English.

• Kuusela, E-mail: kk@mm.unknown

The article presents the background of increment calculations and periodic measurements of forests, as well the historical development of increment calculations in North-America, Middle-Europe, Scandinavia and Finland. The measurements and calculations are presented for individual trees, for a forest stand and for the total resource of a normal forest stand.   

The practice of increment calculations has still some problems regarding the measurements of standing and harvested trees. The article discusses some ways to overcome the problems. 

• Kuusela, E-mail: kk@mm.unknown

The field of work of the 7th National Forest Inventory was carried out during 1977–84. This report consists of the analysis of the forest resources, long-term development of forests and the results by ownership categories in Finland.

The area of forestry land, 26.4 million ha, has decreased slightly because of the increase of build-up areas and communication routes. Forest land, which is suitable to growing wood profitably, amounted 20.1 million ha. It has increased, although not as fast as earlier, due to drainage and fertilization of scrub and waste land swamps and the afforestation of agricultural land.

The growing stock volume was 1,660 million m³ and the estimated gross annual increment 68.4 million m³. A large quantity of young, rapidly growing stands, and fellings markedly below the increment, are the principal factors increasing the growing stock. The volume of Scots pine (Pinus sylvestris L.) has increased most but the greatest proportional increase has been in the volume of broadleaved trees.

The silvicultural quality of stands has improved and the increase in saw log tree volume has resulted in an increase in the total growing stock volume. The proportional volume of saw logs, however, has decreased. Both aging mature stands and postponed thinnings increase the risk of losses due to mortality and decay. Too dense stands retard the diameter growth of trees. The proportion of unsuccessful artificial regeneration has increased.

The area of private forests has slightly decreased, while companies and collective bodies have increased their ownership. Non-farmer private ownership already accounts for one half of the area of private forests. The silvicultural quality of company forests is best and the increase of the growing stock and its increment is proportionally greatest in these forests.

The PDF includes a summary in English.

• Kuusela, E-mail: kk@mm.unknown
• Salminen, E-mail: ss@mm.unknown