Current issue: 53(4)
Under compilation: 54(1)
The study examines the accuracy of volume tables for top measurement of pulpwood boles, and that of top measurement in general in Northern Finland. In this method only top diameter and length of the boles are measured, and the volume is obtained from volume tables. The boles have previously been measured in the middle of the bole, but the method is very time consuming in practice.
The result indicates that the form of both Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) varies greatly. A pulpwood parcel, however, contains both rapidly and gently tapering logs, and the average form differences are much smaller. The difference between the real volume and the volume obtained from the volume tables is generally less than 12% and for more than third of the stock less than 4%.
Pine boles from private forests have been somewhat more and spruce boles less rapidly tapering than boles cut from state forests. The significance of the differences is not clear. Also, the boles in the northern part of the investigation area taper more sharply than those in the southern part.
It is concluded that the accuracy of the top measurement should be improved, but this is only theoretically possible by means of special tables and correction coefficients.
The Acta Forestalia Fennica issue 61 was published in honour of professor Eino Saari’s 60th birthday.
The PDF includes a summary in English.
Sample trees of Betula sp. were felled in North Karelia in different forest site types. The stands, both mixed and pure stands, had been regenerated in areas where shifting cultivation had been practiced. Sample trees represented breast height diameters up to 43 cm. Diameter was measured in distances of 1/10 of the height of the tree to calculate the stem form. The form factor was higher for the good forest site types than the poor sites. The volume tables were calculated based on the assumption that diameter does not affect the form factor. Comparing the volume table to the original data, it was found that the table seems to form a successful fitting of the data. Control data proved that the method seems to give a good fitting to the used data. Thus, the volume table can be used to measure volume of birch stands in North Karelia.
The PDF includes a summary in German.