DIGITALNA ARHIVA ŠUMARSKOG LISTA

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ŠUMARSKI LIST 8/1954 str. 50 <-- 50 --> PDF |

SUMMARY For the construction of local volume tables based on diameter alone (»tariffs«) formulae (1) and (2) can be used. The Croatian text contains a short description of A. Stoffels´work as well as a method of application of the logarithmic paper in the construction of local volume tables mentioned in Meyer´s3 textbook. However, the hypothesis that the line of adjustment is a straight line on the logarithmic paper corresponds only approximately. If on an ordinary loglog-paper we plot several well-known tariffs, we can observe that the corresponding lines are not straight but slightly concave tovards the abscissa axis. In order to avoid this concavity, a special logarithmic paper has been constructed by means of SchumacherHall´s4 logarithmic expression for the tree volume, and the Henriksen5-Emrović´se expression for the stand height curve (see equations (4) and (5). The parameter B magnitude in the equation (5) can be taken on average as B = 6,5 cm (meaning that the height curves would have for their ordinate zero, if the d´ b´h = 6,5 cm, which does not correspond to reality, but this logarithmic curve has only a sense for d b h > 10 cm. By substituting (5) in (4) we obtain (6). By substituting (7) and (10) in the equation (6) we receive the equation (11) — an equation having the form of a straight line on functional paper which has on its ordinate axis an ordinary logarithmic scale, and on the abscissa axis a scale obtained from equation (12). The b parameter in equation (11) is approximately equal to the parameter of the same name in equation (4), thus being independent of the stand height (site class). The volume lines for stands of different height classes (of different site classes) will thus result on this paper in straight parallel lines. This special paper will enable us to determine the slope of the straight line on the basis of data collected from a single stand of a forest complex of the same type, and by means of this slope it is possible graphically or numerically to construct 15—20 tariffs susceptible to be used in the same way as Algan´s tariffs. As an illustration we have constructed graph 1 (on ordinary logarithmic paper) and graph 2 (on special logarithmic paper). The scales of both graphs are reduced to about three — fifths of their actual size. On both graphs are plotted the same lines 1—8 (see Croatian text), in order to enable the comparation. OGLAŠUJTE U ŠUMARSKOM LISTU Tarife za oglase su ove: 1/1 stranica = 15.000 dinara 1/2 stranice = 8.000 „ 1/1 stranice = 4.500 „ (Pošiljalac oglasa dobiva 15%) |