Current issue: 58(5)
Silva Fennica vol. 22 no. 4 | 1988
Category : Article
The two introductory books written by emeritus professor William Duerr provide an opportunity to scope the research progress in the forest economic discipline during almost a quarter century. This paper gives a presentation of the books (Fundamentals of Forest economics, 1960, and Forestry Economics as Problem Solving, 1984), and the development of forest economics during the period.
The PDF includes a summary in English.
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Ollonqvist,
E-mail:
po@mm.unknown
The Academy of Finland commissioned a review of forest regeneration research. This paper summarises the evaluation. The report deals with the individual research projects and, in addition, the international evaluation group gives several recommendations to develop the forest regeneration research further. The recommendations concern education and training, publications, peer review, experimental design, routine work and extension service, and technology transfer. The paper also includes comments of the Finnish Forest Institute, the Finnish Society of Forest Science and a research scientist on the results of the evaluation.
The PDF includes a summary in English.
In Northern Finland as well as in Northern Sweden there is a shortage of high-quality Scots pine (Pinus sylvestris L.) seeds, mostly due to unsuitable temperatures during the development and maturation of cones and seeds. Methods have been developed for elimination of non-productive seeds and for invigoration of seeds. In the present work, these methods were tested on poorly developed seed lot from Rovaniemi, Northern Finland (66°15’–66°30’; 180 m a.s.l.). The seeds were conditioned using the following treatments:
1. PREVAC method (5 min, 97 kPa below atmospheric pressures) for removal of mechanically damaged seeds (7%)
2. Invigoration using incubation at controlled moisture content (30% f.w) and continuous air supply, for 14 days at 5°C.
3. Additional water supply for 16 hours at 5°C.
4. Drying in dehumidified air until a near maximum difference in density between viable and dead seeds was obtained
5. Separation in a sedimentation flume to achieve a gradient of fractions of different germination rate and capacity.
The treatments resulted in an improvement of germination percentage from 33 to about 95% and a reduction in mean germination time from 8.8 days to 6 days if the control and the best fractions (32% seeds) were compared.
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Bergsten,
E-mail:
ub@mm.unknown
The economic analysis is based on computer simulations which covered a seedling rotation and three successive coppice rotations. Calculations were carried out for the four site productivity classes in Eucalyptus globulus plantations. The rotation length that maximized the land expectation value is 12–20 years for seedling rotation and 8–16 years for coppice rotations with discounting rates 2–8%. The mean wood production is over 40 m3/ha/a in the best site class and about 10 m3/ha/a in the poorest class with rotation lengths ranging from 10 to over 20 years. Thinnings increase the wood production and land expectation value by a few percentage points. In areas suitable to Eucalyptus globulus growth, the land expectation value is considerably higher in forestry than in agriculture, except in very poor areas or with very high rate of interest.
The PDF includes an abstract in Finnish.
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Pohjonen,
E-mail:
vp@mm.unknown
- Pukkala, E-mail: tp@mm.unknown
The model computations indicate that the climatic change in the form of higher temperatures and more precipitation could increase the productivity of the forest ecosystem and lead to higher rates of regeneration and growth. More frequent and intensive thinnings are needed to avoid the mortality of trees induced by accelerated maturation and attacks of fungi and insects. The climatic change could support the dominance of deciduous tree species and necessitate an intensification of the tending of seedling stands of conifers. The rise of air temperature during autumn and winter could change also the annual growth rhythm of trees and result in dehardening and subsequent frost damages and attacks of insects and fungi. The pest management could be the greatest challenge to the future silviculture, which could be modified most in Northern Finland.
The PDF includes an abstract in Finnish.
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Kellomäki,
E-mail:
sk@mm.unknown
- Hänninen, E-mail: hh@mm.unknown
- Kolström, E-mail: tk@mm.unknown
Succession of insect attacks on young Scots pine (Pinus sylvestris L.) was studied in heavily, moderately and slightly polluted pine stands within a three-kilometre distance from a prominent emission source in Western Finland. The total number of pest species was highest in the moderately polluted stand, but unlike other herbivores, aphids were also abundant in the heavily polluted stands. A few positive but no negative interactions were detected between herbivores, which suggests that insect species may benefit from a previous occurrence of other species in the same tree.
The PDF includes an abstract in Finnish.
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Heliövaara,
E-mail:
kh@mm.unknown
- Väisänen, E-mail: rv@mm.unknown
The effect of root exposure on the shoot and root development of Pinus sylvestris (L.) seedlings was studied at two soil temperatures. Roots of bare-rooted three-year-old seedlings were exposed to the temperature of 32°C at relative humidity of 50–40% for 85, 155 and 270 minutes which corresponds to accumulated water pressure deficit of 24, 47 and 91 mbar·h, respectively. Thereafter, seedlings were grown for 65 days at the soil temperatures of 12 and 23°C. Drought exposures inhibited new root initiation, delayed shoot elongation, and reduced shoot and needle growth. The stronger the exposure the larger the proportion of needles from the lower part of current shoot that remained undeveloped. Low soil temperature increased the effect of exposures so that needle elongation and initiation of new root tips of seedlings in cold soil with the longest exposure were inhibited totally. Root growth assessments made in warm soil may overestimate the acclimation potential of planted seedlings.
The PDF includes an abstract in English.
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Rikala,
E-mail:
rr@mm.unknown
- Puttonen, E-mail: pp@mm.unknown
The purpose was to analyse the importance of forestry and forest industry in the Finnish economic development since the 1950’s, and to find out how the sector has contributed to the growth of the national economy through other sectors. Data were derived from the input-output tables of 1959, 1970 and 1980. Information provided by Hirschmanian linkages was expanded by taking into account e.g. induced, consumption, final demand and absorption linkages. The linkages of forestry and forest industry had multiplied during the study period. Both final demand linkages and intermediate product linkages were significant. The sector’s contribution to the development of metal and machinery and equipment industries as well as that of energy/water supply was significant. Integration with most other sectors has increased. Indirect production coefficients of forestry and forest industry were larger than on average in manufacturing. Because of labour productivity growth, production and employment coefficients were different.
The PDF includes an abstract in Finnish.
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Haltia,
E-mail:
oh@mm.unknown
- Simula, E-mail: ms@mm.unknown
