DIGITALNA ARHIVA ŠUMARSKOG LISTA
prilagođeno pretraživanje po punom tekstu
| ŠUMARSKI LIST 1-2/1963 str. 11 <-- 11 --> PDF |
ON NUMERICAL THINNINGS SUMMARY In Yugoslavia thinnings are very important and of topical interest because of the abundance of young and middle-aged stands. Therefore this question is given by the Yugoslav forestry a great significance the more so as the previous — old methods — proved not to he always satifactory. It is wished for to pass from the subjective methods over to the more abjective ones. In this connection a definite progress was made and thinnings in recent times are expressed in a numerical manner. Leaving out of account the well-´kncwn thinning methods in France and Germany, the author points to the Netherlands and England, -where the intensity of thinning is expressed by means of the spacing index, which is defined by the quotient between the average spacing of trees and the average height of the dominant trees (top height). This index is undoubtedly very useful for the appraisement of thinning intensities, so that the author .reccmimends it to be introduced also into this country. In addition to this the author refers also to his formula for the intensity of thinning (i), which he derived in »Šumarski List«, No. 9/10, 1953, pp. E m (1.0 pi — 1) 1/q 373—384, viz: i = .100; M = m. 1.0 pi; i = 100; M m- 1.0 p1 1 1 i = (1 ) 100, 1.0 pi q where the symbols used have the following meanings: M = volume of growing stock before thinning; E = volume to be cut in thinning; p = volume growth per cent; 1 = thinning cycle; 1/q = factor cf realization. |