Current issue: 58(5)
The purpose of the study was to determine the effects of the origin of seeds and the location of cultivation of Scots pine (Pinus sylvestris L.) on certain properties particularly important to the pulp industry. The research material consisted of six parallel trials of the same 12 provenances. Increment cores were taken of a total of 1,267 sample trees, 19 years old. The location of the trial site generally affected the properties to a larger extent than the origin of the seed. The effect of the variation of wood density and fibre yield on the cultivation values of the provenances was only a few percentages on average, however, at most the effect was nearly 10%. Eastern Finnish provenances adapted well to western Finnish conditions.
The PDF includes an abstract in Finnish and French.
The objective of the present investigation was to clarify the influence of raw material on the quantity, and especially quality of rotary cut birch veneer by running cutting tests with constant tool setting under factory conditions and with bolts of normal size. The quality of the veneer was mainly examined in laboratory.
The result showed that with an increase in bolt size the yield increases and reaches the maximal value in the diameter range of 251–275 mm and 226–250 mm for 60-inch and 50-inch bolt, respectively. With a decrease in bolt length the yield becomes higher. With the increase in the bolt size the quality of the veneer improves.
Defects in the shape of the bolt, such as crookedness, taper and oval form, decrease the yield. The good quality of the bolts affects most the yield of full-size sheets. Increase of knottiness decreases the yield by 4–5%. Lowering of the bolt temperature below 0 °C causes a sharp decline in the yield. Moisture content of the wood did not markedly affect the yield, but it improved the quality of the veneer. The minimum moisture content was 75%.
For the technical quality of the veneer, bolt temperature was the most decisive raw material factor. Also shape defects, of which crookedness was most serious, decreased the technical quality. Increase in summerwood percentage improved the quality.
The PDF includes a summary in English.
The aim of the study was to explain the regression between the cubic content of the trunk of a tree and of logs cut from the trunk. The minimum size of trunk that can be used to saw logs has been 18 feet long and 5″ of top diameter in Finland (in 1930s). The average length of logs is 16‒18 feet. The data of this study was collected in seven areas around Finland. The results show that there is regression between the volume of the trunk, the volume and the logs cut from the trunk and the number of logs. Consequently, it is possible to determine the average regression between the trunk and log sizes for forest technical purposes. The regression varies in different parts of the country due to varying growth condition of the trees and different age classes. It is probable that the figures have to be re-examined in the future.
The PDF includes a summary in English.