Silva Fennica vol. 11 no. 4 | 1977
Category : Article
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.
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Järvinen,
E-mail:
oj@mm.unknown
- Kuusela, E-mail: kk@mm.unknown
- Väisänen, E-mail: rv@mm.unknown
The structural matter production of selected plant species of a ground cover community was determined in relation to light available for photosynthesis. The resulting functions were applied in a situation where the light reaching the ground cover was controlled by the dynamics of the tree crown strata, and the occurrence of different plant species at different stages of succession was determined on the basis of their production of structural matter in actual light conditions. The possible strategies involved in adaptation to a successional environment have been discussed.
The PDF includes a summary in Finnish.
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Kellomäki,
E-mail:
sk@mm.unknown
- Hari, E-mail: ph@mm.unknown
- Kauppi, E-mail: pk@mm.unknown
- Väisänen, E-mail: ev@mm.unknown
A quantitative method for determining the annual growth level of plant species has been presented. In particular, attention was paid to the dependence of the growth level on the amount of light available for photosynthesis. A mathematical model for the dependence of structural matter production on photosynthetic production has been presented for some plant species.
The study is based on the assumption that the total amount of annual net photosynthesis plays a role of primary importance in determining the relationship between photosynthetic production and structural matter production. The basic environmental factors determining the photosynthetic rate are light and temperature, if the water and nutrient supply is adequate. The dependence of photosynthetic rate on light and temperature was determined by monitoring the CO2 uptake rate of natural plant populations between the photosynthetic levels of different plant populations with an infrared gas analyser.
The PDF includes a summary in Finnish.
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Väisänen,
E-mail:
ev@mm.unknown
- Hari, E-mail: ph@mm.unknown
- Kellomäki, E-mail: sk@mm.unknown
The aim of the paper was to investigate the potentials offered by trails in guiding recreational activity. The study is based on interviews and questionnaires concerning recreationists using two recreation areas owned by the city of Helsinki in Southern Finland. According to the results, the recreationists visit terrain without trails every time they visit a recreation area. The main reason for this was obtaining varying recreational experiences. The recreationists used, however, the same route nearly every visit, which suggests that trails have a great potential in guiding reacreational activities. Special attention was paid to the role of trails in activities involving physical exercise. The correlation between the socio-economic background of recreationists and their preferences for trails was very low.
The PDF includes a summary in English.
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Kellomäki,
E-mail:
sk@mm.unknown
The physical strain put on forest workers and work time consumption during pulpwood cutting were compared when the bolts were stacked at the side of strip road, the strip road spacings being 15–25 m and 26–35 m, and when stacked at scattered points along the cutting strip.
When stacking at scattered points along cutting strip work time consumption was 17–21% and the heart rate 9–12% less than when stacking at the side of the strip road, strip road spacing being 15–25 m. When the strip road spacing was increased to 26–35 m, the time consumption increased by 18–30%, but the heart rate appeared unchanged. This result suggests that the forest worker compensates for increased physical strain caused by an increased stacking distance by changing his working technique and rate and by increasing the number of his breaks.
The PDF includes a summary in English.
-
Valonen,
E-mail:
pv@mm.unknown
