Current issue: 57(2)
Under compilation: 57(3)
The purpose of this investigation was to study the felling volume and its structure in the State forests of Finland. Special attention was paid on the proportion of waste wood within the felling volume. This information was in demand for the general plan of the State forests that was being prepared at the same time. The survey was performed using a sampling method, and it represented the districts in the northernmost Finland, Ostrobothnia, Eastern Finland and Western Finland of the Forest Services.
The proportion of merchantable timber of the total felling volume was lowest in the northernmost Finland, less than 2/3 of the total cut. In Ostrobothnia the share was ¾, Eastern Finland 4/5 and in Western Finland 5/6. When the tree species were compared, the proportion of waste wood was largest in broadleaved trees, especially in the Northern Finland, while for Scots pine it was lowest. For Norway spruce the share of merchantable timber is markedly lower in the northernmost part of the country, where, for instance, decay increases the proportion of waste wood. For birch, demand of wood influences most the proportion of waste wood.
In general, the proportion of waste wood and merchantable timber in the felling volume was influenced by changes in the demand of timber, structure of the stands, and the felling method. The demand of the timber assortment affects most in the amount of waste wood. The more valuable the timber assortment is, the less waste wood is left in the cutting area.
The PDF includes a summary in German.
This investigation concerns the felling volumes in Finland in 1935-1945 as regards future fellings. The statistics are divided in two time periods: 1935-1939, when there was an upward trend in the trade cycle, and 1940-1945, when the trade was disturbed by the Second World War. Fellings of household timber and for sales are presented separately.
Removal was annually in average 38.1 million cubic meters (cbm) without bark in 1935-1939, and 29.8 million cbm in 1940-1945. According to the statistics, felling volumes decreased by about one quarter after the period of 1935-1945. Reduction was largest in private and company forests, but smaller in the state forests. The increment balance for the 1935-1945 shows an excess of growth that gives an accumulated yield of 24.4 million cbm.
In private forests the cut is about half as large as the growth of the standing stock due to the poor silvicultural condition of the forests. Private forests account for about ¾ of the total forest area in Finland. In the state lands the cut is 130% of the growth. The report introduces also rental cut, a method developed by the writer, which defines the volume to be cut aiming at the same time to optimise the future increase of the yield. The principle is to preserve the young and vigorous stands, while cutting stands that have low growth.
According to the statistics, the felling volume of private forests has followed the variations in demand. It seems likely that in the coming years the fellings will not be kept within the limits calculated by the rental cut. Consequently, the reserve formed during the war will be utilized. To meet the demand of wood, forest management must be improved and preference should be given to regeneration fellings. Improving transportation systems, such as roads, would give access to forest resources that are now difficult to harvest.
The PDF includes a summary in English.
The effect of different kinds of injuries in the amount of merchantable timber was studied in 57 sample plots in the northernmost Finland. Without any injuries the yield of timber would have been 72.3% in Scots pine (Pinus sylverstris L.) and 89.9% in Norway spruce (Picea abies (L.) H. Karst.). Butting, and removal of parts of the stems due to Injuries decreased the volume by 10.4% in pine and 13.5% in spruce. The main cause for butting of pine was fire wounds, and butt rot in spruce. Also pine blister rust (Peridermium pini and Cronartium flaccidum) causes injuries in Scots pine. The better the forest site type, the smaller is the timber discarded due to injuries. In pine 54% and in spruce 53% of the trees and were healthy. The forests in the northernmost Finland are over-mature which increase the occurrence of fire wounds and decay. Thus, forest fire control and the felling or thinning of over-mature stands will improve the quality of the timber in the long run.
The PDF includes a summary in German.