Silva Fennica no. 119 | 1966

In the 1930s studies showed that state of the standing crop and forests of small private forest holdings in Finland was weak. In 1960s it was regarded necessary to study the possible change in the silvicultural state of these forests. Therefore, sample stands of the small holdings surveyed in 1930 by Osara were surveyed anew in the areas of Karelia and Savo, and in Central Finland in 1963–1964. A line plot survey was combined with ocular estimation as in 1930, but in 1963–1964 the lines and sample plots were placed denser than in 1930 to reach similar number of sample plots.

In 1930 the state of the forests of the small holdings was in average very weak, but according to Osara, the age classes younger than 50 years had similar stand volume than in the all the forests of the southern half of the country. The results of this survey show that the volume, structure, growth and development class structure of the forests in average have improved since 1930. In many respects the forests have reached the average state of forests in the southern half of Finland. The most serious problem is the large proportion of broadleaved trees. Thus, the silvicultural state of the forests should be further improved.

The PDF includes a summary in German.

• Ilvessalo, E-mail: mi@mm.unknown
• Ilvessalo, E-mail: yi@mm.unknown

Stand precipitation and stemflow studies became necessary in connection with hydrologic studies, for instance, to explain the deviations resulting from rains in the ratios between the water content of peat and the groundwater level, throughfall during rains of variable heaviness, and effect of stand treatment on soil moisture level. In this project the distribution of rainfall in stands differing in species composition and density was studied in Central Finland in 1963–1965 in fifteen stand precipitation sample plots. In addition, rain gauges were situated under individual Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst.) and birch (Betula sp.) trees.

The average precipitation in the open was 4.8 mm, the corresponding precipitation in the stand was 77% for birch, 71% for pine and 62% for spruce. Measurements of stemflow from individual sample trees showed that less than ¼ mm (about 1.5%) during a 15 mm rain in a pine stand. In the spruce stands stemflow is negligible. A part of the sample plots was in drained peatlands with a dense vegetation of small shrubs. The shrub layer retention was about 10% even during heavy rain. In a small forest clearing, the bordering effect of the forest was seen up to the distance of 5 metres from the edge of the forest. During the period of study, on an average 3% more precipitation was recorded in the clearing than in the open, the difference being probably due to the stronger wind effect in the open.

The PDF includes a summary in English.

• Päivänen, E-mail: jp@mm.unknown

This paper describes the preliminary results of Scots pine (Pinus sylvestris L.) seeding and planting trials on drained peat soils.

The results showed that a perpared peat surface was a better surface for seeding than the unprepared one. Planting of 2+1-year seedlings succeeded better than planting 1-year seedlings. Planting on the turf gave better survival than planting on the unprepared soil surface. The whole growing season was suitable time for planting Scots pine seedlings except May when the peat soil under the surface was still frozen.

Using fertilizers in connection with planting was surveyed in two ways. Mortality of seedlings increased when they were top-dressed with NPK fertilizer. Using a so-called spot fertilizing with several combinations of fertilizers resulted in K and N tending to increase the mortality of seedlings, but P decreasing mortality.

The PDF includes a summary in English.

• Heikurainen, E-mail: lh@mm.unknown
• Päivänen, E-mail: jp@mm.unknown
• Seppälä, E-mail: ks@mm.unknown

The aim of this project was to investigate the cellulose decomposition rate in the soil on the ecological conditions created by different tree species, particularly birch (Betula sp.) and Norway spruce (Picea abies (L.) H. Karst.). Therefore, comparable sample plots were established in adjoining birch and spruce stands. Data on the stands, the vegetation, and the soil in the sample plots were collected. The experiment was carried out in the Ruotsinkylä Experimental Forest near Helsinki in Southern Finland.

Five pieces (3x5x0.15 cm) of cellulose (bleached sulphite pulp) were dried, weighed, and fastened in a row into a nylon bag. The bags were placed into the soil at a slant so that the upmost piece of cellulose was in the depth of 0–1.5 cm and the bottom one 6–7.5 cm. The weight losses of the pieces were measured after periods ranging from 6 to 12 months.

The results show that even within the same forest type, decomposition is much more rapid in birch stands than in spruce stands. In all the stands the decomposition rate decreased rapidly with increasing depth. The difference between birch and spruce stand, as well as the decrease with increasing depth, was probably mainly due to different thermal conditions.

The PDF includes a summary in English.

• Lähde, E-mail: el@mm.unknown