Articles containing the keyword 'kuusitukki'

In order to evaluate the strength properties of boards made from small and large Norway spruce (Picea abies) butt logs, 15 small (top end diameter 13 cm) and 15 large (top end diameter 25 cm) logs were sampled from a sawmill in Finland. From each log two test pieces were made in order to measure the bending and compression strength, dry density and average ring width.

The boards from small logs were stronger and their density higher. When the differences between groups were analysed it was found that the strength was determined by the density and ring width. When the density was kept constant, the increase in ring width had a decreasing effect on the strength properties. Because there was a negative correlation between ring width and density, ring width alone had a great effect on the strength properties.

The PDF includes a summary in English.

• Kärkkäinen, E-mail: mk@mm.unknown
• Hakala, E-mail: hh@mm.unknown

The aim of the present study was to find the factors influencing the distribution of Norway spruce (Picea abies (L.) H. Karst.) logs on various grades with special stress on the effects of the grade on the value of logs. The material was obtained from ten sawmills located in Southern Finland by grading a total of 13,559 logs.

The results showed that knottiness in its different forms of appearance is the most important factor influencing the quality of spruce logs. Its significance is clearly greater in spruce than in Scots pine saw logs. Among the other defects, the most common are crooks. Even scars and decay occur to a considerable degree, but other defects seldom affect the grade. The quality of butt logs is markedly better than that of top logs. Both in butt and top logs the smallest logs in diameter are of poorer quality. However, in the largest diameter classes the quality begins again to decrease.

The difference in the quality of logs of the same grade at various sawmills is very small. The results of grading at varying times at the same sawmill show greater differences than can be observed between different sawmills. However, the logs of sawmills that procure the timber from coastal areas and islands are inferior to those which procure the timber from the mainland.

The PDF includes a summary in English.

• Heiskanen, E-mail: vh@mm.unknown

Due to shortage of large logs, sawmill industry has been forced to buy also smaller logs, which also pulp industry uses as a raw material. Sawmills must be careful in the pricing of the logs, because profitability of sawing of timber depends on the size of the logs. These industries use different measures when they buy timber: pulp industry uses piled measure in meters, while saw logs are measured individually in cubic feet. The aim of the study was to develop sets of figures on technical cubic measure of a saw log and its relation to a piled cubic meter from the same log used as pulp wood. In addition, the effect of form class on the measures was studied.

The relation was assessed for trunks that had good, mediocre or unfavourable form class, which distinction is easy to make for a forest worker buying timber. The relations can be used by a buyer of saw logs or pulpwood who need to compare the prices or when the seller of the wood compares the offers.

The PDF includes a summary in German.

• Wuoti, E-mail: ew@mm.unknown