Silva Fennica vol. 16 | 1982

In forestry, a classical method of evaluating the profitability of an outlay is to calculate the internal rate of return. If there are many outlays and returns over a period, analytical determination of the internal rate is difficult and requires simulation methods. However, if there is only one outlay and one return, the computation is easy. In this paper, some formulae were developed for practical purposes. The equations also show how the return changes as the ratio between the return and the outlay changes.

The PDF includes a summary in English.

• Kärkkäinen, E-mail: mk@mm.unknown

Application of nitrogen at levels of 200, 400 and 600 kg ha^-1 resulted in increases of 35, 18 and 12% in the photosynthetic rate in young Scots pine (Pinus sylvestris L.). The number of buds, degree of branching, and needle size were positively related to the amount of nitrogen applied. A 10–40% increase in the average needle area was found. A positive correlation was found between total photosynthesis and stem growth.

The PDF includes a summary in Finnish.

• Kellomäki, E-mail: sk@mm.unknown
• Puttonen, E-mail: pp@mm.unknown
• Tamminen, E-mail: ht@mm.unknown
• Westman, E-mail: cw@mm.unknown

Relationships between densities of pine bark bug, Aradus cinnamomeus Panzer and the height growth of young Scots pine (Pinus sylvestris L.) were studied in several habitats, including a highly infested area in Southern Finland. The slower the growth of the pines was, the greater was the height up to which bugs were found. On the average, maximum bug density was noted at a height corresponding to a fifth of the height of the tree. In stands restocked by natural generation, the greatest bug densities were noted in pines about three metres high and over twenty years old. Bug densities in trees whose height growth had been decelerating for five years were twice those in trees whose growth was accelerating. A significant negative correlation was found between the bug density and the last-year height increment.

The PDF includes a summary in Finnish.

• Heliövaara, E-mail: kh@mm.unknown

The monoterpene composition of the needle oil of Pinus oocarpa Schiede ex Schltdl. and Pinus caribaea Morelet growing in Zambia were studied by means of GC-MS. P. oocarpa needle samples were taken from 29 trees representing different clones in a seed orchard and from 43 trees in a commercial plantation in 1980. The P. caribaea needle samples were collected from 17 clones in a seed orchard.

Nine compounds were positively identified in the monoterpene fraction of P. oocarpa and eight in that of P. caribaea. The amounts of these compounds showed marked tree-to-tree variation and the sample trees were screened into distinct groups on the basis of the variation. The results give a basis for selection in favour of pest resistance and turpentine yield.

The PDF includes a summary in Finnish.

• Löyttyniemi, E-mail: kl@mm.unknown
• Hiltunen, E-mail: rh@mm.unknown
• Löyttyniemi, E-mail: rl@mm.unknown
• Räisänen, E-mail: sr@mm.unknown

A material consisting of 21 common alder (Alnus glutinosa (L.) Gaertn.) trees from 11 stands was collected. From each stem discs were sawn by 2 m interval. Samples were taken of the discs from various distances from pith. They were macerated and the average fibre length was based on 50 observations.

The fibre length increased significantly from the pith to the disc surface. The increase was approximately similar at various heights of the tree. The tree characteristics had only minor effect. However, near the pith the increase in fibre length was higher in trees with wide growth rings than in other trees. Near the disc surface the growth rate had no effect. In typical pulpwood bolts the average length was 800–950 μm which corresponds well to the data given in the literature.

The PDF includes a summary in English.

• Haarlaa, E-mail: rh@mm.unknown
• Kärkkäinen, E-mail: mk@mm.unknown

Certain trends in the sales behaviour of private non-industrial forest owners suggest that the forest industries have to rely on a raw material supply much less than the allowable cut. This paper deals with several factors responsible for the change in sales behaviour during the last 20–25 years. These changes are caused by social change, a multi-face process which is led by industrialization. It is manifested in the increasing division of labour, more pronounced strive for efficiency, change in social values for the benefit of the adoption of innovations and thus of further changes.

It has become more common than previously to borrow money instead of selling timber. An incentive for doing so is provided by the increased progression of income tax scales which makes it more profitable than earlier to substitute a loan for timber sales with a view to reduce the amount of taxes. In 1977, the real value of the farmers’ debts was 1.7 times as large as in 1970. Inflation provides a further incentive to borrow money rather than to sell timber, because it tends to reduce debts, whereas a growing stock keeps increasing without affecting the property taxation, maintaining its real unit value.

Certain forestry policy measures conductive to increasing the forest owner’s willingness to sell timber are suggested. Among the most promising seems to be an adjustment of the present area-based yield taxation so as to take into account the age class distribution of the growing stock.

The PDF includes a summary in Finnish.

• Riihinen, E-mail: pr@mm.unknown

The purpose of this study was to measure workers’ exposure to MCPA and glyphosate when sprayers connected to the brush saws was used. A non-pressurized sprayer with a pump and a pressurized sprayer where dosage was regulated with manual control were studied. Exposure was measured from the breathing zone and urine samples.

MCPA collected from the breathing zone gathered into alcohol was 0.05 mg/m³ for the pressurized sprayer, 0.02 mg/m³ for the non-pressurized sprayer, and 0.04 mg/m³ (average) for both types of sprayers together.

MCPA in the breathing zone, collected from splashes and fog into a glass fibre filter, was 0.18 mg/m³ for the pressurized sprayer, 0.09 mg/m³ for the non-pressurized sprayer, and 0.12 mg/m³ for both sprayers used together. Glyphosate in the breathing zone, collected into sodium hydroxide was below 0.05 mg/m³.

In five urine samples taken after the work day there was on the average 0.4 mg/l MCPA, while in 21 samples the MCPA contents were under the definition limit (0.2 mg/l).

The PDF includes a summary in Finnish.

• Kangas, E-mail: jk@mm.unknown
• Klen, E-mail: tk@mm.unknown

The aim of the paper was to describe the development of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) seedling stands on drained peatlands and to find out the principal factors influencing their growth. The material under survey consists of 180 sample plots distributed from southern coast of Finland to the Polar Circle.

The most important growth factors have been the accumulated temperature sum, site quality, drainage intensity and silvicultural condition, such as the density of the stand, the proportion of birch in the stand, and the amount of possible shelterwoods. The influence of these factors, and to some extent the influence of fertilizing, and the disturbing effects of some forest damages, such as frost, growth disturbances and elk damages were investigated. Comparisons of the development in the seedling stands on drained peatlands with the known development of seedling stands in mineral soils were made.

The PDF includes a summary in English.

• Heikurainen, E-mail: lh@mm.unknown

Planners of the Soviet pulp and paper industry are constantly faced with the problem: which investment policy guarantees the best location structure? Should one invest in existing localities or expand to new areas, especially in heavily forested parts of Siberia? A location theory for the pulp and paper industry, based on three factors (markets, wood raw materials, relative costs) has been suggested by the Soviet authors Antonov and Trusova. In the present study the theory is – for the first time – given empirical contents and the feasible areas for future growth of the industry are tentatively determined. One of the main findings of the study is the detecting of considerable unutilized wood reserves in the European USSR. This supports those Soviet views advocating a European-oriented location in investment strategy for the industry, as market and cost factors are unfavourable to Siberian location.

The PDF includes a summary in Finnish.

• Eronen, E-mail: je@mm.unknown

The study discusses the amount of shrinkage of volumetric undisturbed peat samples when drying to an oven-dry (105°C) condition. The amount of shrinkage is related to various physical properties of peat. In addition, some observations were performed on the shrinkage phenomenon during the drying process. The study results may be used when predicting the shrinkage of peat samples with various peat properties. Knowledge of this kind is particularly important in connection with peat harvesting.

The PDF includes a summary in Finnish.

• Päivänen, E-mail: jp@mm.unknown

The publication comprises proceedings of a conference held in Helsinki in 1981. Forest tree populations are investigated for population genetic structure, mating systems, mechanisms of genetic adaptation and ecological adaptation. Methods and techniques used in population genetic research of forest trees are presented. Much concern is given to applications by means of forest tree breeding, particularly the seed orchard breeding technique. Generally, the application of population genetics in cultivated forests is discussed.

The PDF includes a preface and the presentations of the conference (25 short papers) in English, and a comprehensive summary of the themes of the conference in Finnish.

• Tigerstedt, E-mail: –

This paper is a book review on a German text book for university education ’Waldböden’ by Karl E. Rehfuess, which concentrates on forest soil science.

• Westman, E-mail: cw@mm.unknown

The purpose of the seminar, arranged by the Finnish Society of Forest Science, was to instigate discussions which would bring up new approaches and research methods for studying forestry problems from both the biotechnical and socio-economical fields. Six papers were presented and over 70 opinions aired at the seminar.

The following points were considered especially important from the point of view of the promotion of forestry research

- Improving contacts between forestry and other branches of science and increasing international exchange of ideas and results.

- Improving the effectiveness of research work through sound planning

- Promotion and gaining benefit from diverse forms of research.

- Arranging the further education of researchers in order to improve the professional standards of researchers.

The PDF includes a summary in English.

• Finnish Society of Forest Science, E-mail: –

A mature Scots pine (Pinus sylvestris L.) stand growing on a site of the Vaccinium type in Southern Finland was fertilized with nitrogen-rich NPK fertilizer at a level of 150 kg pure nitrogen per hectare. The sample plots were also irrigated during four growing seasons. The total amount of irrigation during this period was 1,200 mm. Fertilization alone increased the coverage of grasses and dwarf shrubs. The culmination of the increase occurred during the second growing season after the start of the treatment. The rapid effect of irrigation on the coverage of ground vegetation was not so strong as that of fertilization. It was concluded on the basis of the developed growth model that the coverage of dwarf shrubs, especially Calluna vulgaris, was, however, increased with the fertilization treatment for a prolonged period. Fertilization and irrigation had no visible effect on the coverage of lichens and mosses.

The PDF includes a summary in Finnish.

• Mälkönen, E-mail: em@mm.unknown
• Aro-Heinilä, E-mail: va@mm.unknown
• Kellomäki, E-mail: sk@mm.unknown

Good correlation between radar reflection depth when using a FM-CW radar during winter and bearing capacity measurements during spring breakup was found. Therefore, it might be possible to evaluate the bearing capacity of forest roads using the radar sounding technique.

The PDF includes a summary in Finnish.

• Saarilahti, E-mail: ms@mm.unknown

Eighty Betula nana samples were collected from three swamp sites. In the butt portion of the dwarf shrub the average number of growth rings was 12 and the average diameter of the sprouts 6 mm. The basic density of wood was 457 kg/m³ and that of bark 544 kg/m³. The proportion of bark was 32–38% of weight or volume. The vessel elements and fibres were short and their diameter small. The proportion of vessels was 15%, that of fibres 70% and that of rays 15%.

The PDF includes a summary in Finnish.

• Bhat, E-mail: kb@mm.unknown
• Kärkkäinen, E-mail: mk@mm.unknown