Silva Fennica vol. 11 no. 1 | 1977

The aim of the present paper was to study the annual production of Pleurozium schreberi (Brid.) Mitt., Hylocomnium splendens (Hedw.) B.S.G and Dicranum polysetum Sw. as a function of light available for photosynthesis. The productivity of the above moss species is studied using the harvested quadrats method in Norway spruce (Picea abies) stands of the Myrtillus site type representing different stand density classes (basal area from 0 to 34 m2/ha) in Southern Finland.

The annual production of each species in different stands was correlated with the amount of light available for photosynthesis i.e. with the photosynthetic production. Functions for the dependence of productivity on light conditions were produced for each species. The individual functions and their ecological significance is discussed. The adaptation of each species to low light intensity is evident since no meaningful addition to production takes place when the photosynthetic light ratio reaches values greater than 0.3–0.4. In other words, the level of photosynthesis which is 30–40% of that possible in the open, provides sufficient supply of carbohydrates or the basic functions of the moss species studied. Pleurozium schreberi and Dicranum polysetum seem to have greater light requirements than Hylocomnium splendens.

The PDF includes a summary in Finnish.

• Kellomäki, E-mail: sk@mm.unknown
• Hari, E-mail: ph@mm.unknown
• Väisänen, E-mail: ev@mm.unknown

This study, comprising three experiments, aims to determine the effect of the geographical origin of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) seeds, and the duration of the time lag between the moisture treatment and subsequent irradiation on the gamma-irradiation sensitivity of seeds.

The studies showed that the greater the irradiation dose seeds were subjected to the slower the rate of germination. In general, small radiation doses (250–1,000 rad) had a stimulating effect and the final germination percentage (36–40 days) increased. However, when the level was further increased, the germination percentage decreased. Air-dry and moistened seeds withstood irradiation better than others. In a study with moistened seeds from different geographical sources, pine and spruce seeds from Northern Finland were less able to withstand irradiation than those originating from the south.

The PDF includes a summary in English.

• Lehtiniemi, E-mail: tl@mm.unknown

The aim of this study was to determine under what conditions and with what premises the growing of Betula pubescens Ehrh. is an economically competitive alternative to the growing of Scots pine (Pinus sylvestris L.) in drained peatlands. The basic material consisted of all drainage projects in Ostrobothnia in Western Finland in 1937–38 and 1957–59, according to the archives of the Central Board of Forestry Tapio, including such areas that were at least moderately fertile and had birch dominated young stands or no tree cover. A total of 202 sample plots were measured.

According to the results, the discounted timber yield of the thinned B. pubescens stands is about 10% greater than that of untreated stands. The removing of birch seedlings and the subsequent growing of fully stocked Scots pine is more profitable than growing B. pubescens stands only if the establishment and subsequent development of the pine stand involve no costs. If the site in question is a fertile open drained peatland, establishment of a pine stand is obviously a better financial proposition than a naturally regenerated birch stand. However, if there is already a fully stocked young birch stand on the site, it is more economical to let it grow using a shortish rotation time.

The PDF includes a summary in English.

• Keltikangas, E-mail: mk@mm.unknown
• Seppälä, E-mail: ks@mm.unknown

In the densely populated Central Europe, forestry has always had different functions than in Scandinavia or Canada. Today the increasing pressures on the environment and more numerous demands of the people have put emphasis on environmental management and the demands of recreation in forest management practiced in the area. This paper outlines the trends in the utilization of forests in Central Europe, and especially in the Federal Republic of Germany, due to these changing targets. The regulations concerning forestry in Baden-Würtenber, and the forest plan of the Bavarian state forests are used as an example to clarify the principals of forest management and planning.

• Schmidt-Vogt, E-mail: hs@mm.unknown

In most pine swamp stands on drained peatlands the dwarf-shrubs are rather important biomass producers. The aim of the experiment was to determine the effect of killing off the dwarf-shrub vegetation on the subsequent development of Scots pine (Pinus sylvestris L.) stand. The dwarf-shrub vegetation was killed by means of herbicides. The results show that by removing competition by the dwarf-shrub vegetation on drained pine swamps, it is possible to pass onto the trees at least some of the freed growth potential.

The PDF includes a summary in Finnish.

• Sarasto, E-mail: js@mm.unknown
• Seppälä, E-mail: ks@mm.unknown

In the boreal zone, the environmental control of growth rate, i.e. the rate of irreversible change in shoot dimensions, is assumed to be dominated by temperature. Promnitz (1975) emphasises that in boreal and temperate zones storage of photosynthetic products is an essential part of the growth process, and thus direct interaction between growth rate and radiation is not evident. The aim of the present study was to investigate the control of daily structural matter production in populations of Avenella flexuosa (L.) Drejer. Special attention was paid to the role of temperature and radiation in addition to the self-regulation of the plants themselves.

Temperature and self-regulation were found to explain over 90% of the daily variation of growth rate. Introduction of radiation into the analysis did not increase the explanatory power of the growth model based on temperature and self-regulation.

The PDF includes a summary in Finnish.

• Lehtonen, E-mail: il@mm.unknown
• Hari, E-mail: ph@mm.unknown
• Kellomäki, E-mail: sk@mm.unknown
• Väisänen, E-mail: ev@mm.unknown

According to the available literature, the appearance of Parana pine (Araucaria angustifolia (Bertol.) Kuntze) wood resembles that of Scots pine (Pinus sylvestris L.). The anatomy is quite different, however. There are no resin canals and fusiform rays with resin canals in Parana pine. They are abundant in Scots pine, however. The basic density of Parana pine is higher. In both species the density increases from the pith outwards, the maximum being reached at the age of 100 years. Compression wood is more common in Parana pine than in Scots pine, and this makes the longitudinal shrinkage of Parana pine greater than that of Scots pine. Otherwise the shrinkage properties do not differ. The mechanical strength is of the same magnitude with the exception of hardness, where Parana pine is superior.

The PDF includes a summary in English.

• Kärkkäinen, E-mail: mk@mm.unknown

In 1975 the roundwood transport in Finland, which was mostly floated in the inland waters, accounted for 45% of the total transport performance and for 25% of the total transport volume. The paper describes the Finnish inland waterway fleet in 1975. The information was collected from the material of navigation inspectors who yearly inspect the seaworthiness of the merchant ships. The number of inspected vessels was 778. Of those 495 were tugs, 118 passenger boats, 71 warping boats, and the others totalled 94. The average power of tugs was 65 kW and that of warping boats 16 kW.

The PDF includes a summary in Finnish and French.

• Roitto, E-mail: yr@mm.unknown