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ŠUMARSKI LIST 1-2/1958 str. 22     <-- 22 -->        PDF

Lötsch F., Das Tarifdifferenzverfahren zur Massenzuwachsermittlung, Schweiz.
Z. Fortsw. 1954.
[4] Prodan M., Messung der Waldbestände, 1951.
[5] Klepac
D., O Šumskoj proizvodnji u fakultetskoj šumariji Zalesini, Glasnik za
šumske pokuse, br. 11, 1953.
[6] Klepac D., Komparativna istraživanja debljinskog, visinskog i volumnog prirasta
u fitocenozi jele i rebrače, Sum. list, br. 2/3, 1954.
[7] Klepac
D., Istraživanje debljinskog prirasta jele u najraširenijim fitocenozama
Gorskog Kotara, Glasnik za šumske pokuse, br. 12, 1956.
18] Tischendorf W., Die Genauigkeit von Messungsmethoden und Messungsergebnissen,
Forstwiss. Cbl., 1925.

Levaković A., K pitanju raspoređivanja primjernih stabala među pojedine debljinske
skupine, Glasnik za šumske pokuse, broj 3, 1931.

The volume increment is equal to the product of diameter increment and slope
of tariff line [see equation (1)]. An erroneously selected tariff will yield an error of
systematic character. Therefore the random error of volume inerement will depend
on the slope of the tariff line, the number of cores and the standard deviation of
diameter increment. This standard deviation (o2X) — in all diameter classes arising
in practice — is constant in a given stand, and independent of the aize of d. b. h.
This was presumed in the papers of Meyer [1] and Loetsch [2] [3] without any proof.
Here we have proved it on the material collected by Klepac [5] (see Table 1). On the
supposition that 2X is linearly dependent on d. b. h. [see equation (6)], the parameter
b should be significantly different from zero, which actually is not the case (see
Table 2). Consequently, the error of the total stand volume increment is given by
equation (8), and it will be minimum, if the increment cores are distributed within
the diameter classes according to equation (14). The deduction [of eqations (9) — (14)J
is similar to that used by Tischendorf [9]. On the supposition that the tariff line has
the equation (15), the proportion in equation (14) assumes the form

Pi : P2 : P3 : "" nj: xi: n2 X2 : ns xs :
(py — number of cores in the ith — diameter class,
n; = number of stems in the i´1 — diameter class,

x: = average diameter in the i´* — class)
In this case maximum accuracy (i. e. minimum error) for a definite number of
cores will be attained.