DIGITALNA ARHIVA ŠUMARSKOG LISTA
prilagođeno pretraživanje po punom tekstu
| ŠUMARSKI LIST 11-12/1958 str. 40 <-- 40 --> PDF |
veća, nego na silikatnoj podlozi (~ prijelaz sastojine od jednodobnog tipa na preborni). Prema tome može se reći, da će se na temelju strukture sastojine po broju stabala moći nešto zaključiti o veličini parametra b. Nadalje na veličinu parametra b i c vjerojatno utječu i ostali faktori kao: vrst drveća, ukupna temeljnica po hektaru, bonitet i starost (za jednodobne šume), a to su veličine, koje su već određene i poznate na objektu, kad se na njemu određuje prirast. Svi ti faktori vjerojatno utječu na veličinu parametra b i c, ali njihov utjecaj već sada naji moguće ustanoviti, jer nam na raspolaganju stoji premalen broj izmjerenih pokusnih ploha. Kad bude izmjeren i poznat veći broj podataka (kad bude snimljeno dovoljno pokusnih ploha u sastojinama sa različitim vrstama drveća i različitih boniteta i načina uzgoja), možda će se moći odrediti utjecaj tih faktora i pronaći način, da se iz veličine tih faktora odrede iznosi b i c, pomoću kojih bi se onda odabrao najprikladniji funkcionalni papir i nagib pravca. LITERATURA [1] Klepa c D., Funkcionalni odnos između godišnjega volumnog .prirasta i prsnog promjera za jelu u prebornoj šumi, Šum. list, 1/2 1959. 02] Levakovi ć A., Analitički oblik zakona rasterija, Glasnik za šumske pokuse, br. 4, 1935. [4] Emrovi ć B., O izjednačenju pomoću funkcije, koja se logaritmiranjem daju svesti na linearni oblik, Glasnik za šumske pokuse, br. 11, 1935. [5] Klepa c D., Utvrđivanje prirasta po metodi izvrtaka, Šum. list, 11/12. 1955. SUMMARY The graphical representation of the interdependence of annual volume increment and d. b. h. is in the form of an S-line. If, for this S-line, we take the equation of growth function after Levakovi ć ]2] [see the equation (1) y = zv = one-year increment of one tree in cu. m.; x = d. b. h. in cm.; a, b, c = paremeters of the equation (= constants)], and assuming the parameter b to take an average value e. g. b = 20, then, after equation (3) obtained by means of anamorphosis, i. e. the logarithmation of the equation (1), it is possible to design a special functional paper on which the plotted volume-increment lines will approximately be represented by straight lines. In practice the straight line can be plotted by the use of the method of x averages. For the computation of the amounte 1 = log are given tables 1 20+ x and 2. In order to make possible a plotting of the average coordinates of groups, there were drawn on the paper also the linear scales I and JJ. On the original paper sized 210/297 m. m. (see its reduced picture on page ) were plotted data of the volume increment of two selection-type stands from the Fir forests of »Gorski Kotar« (mountainous region in South-western Croatia) as v/ell as the data of an even-aged stand of Pedunculate Oak from the lowlands (along the Sava river) (see Klepa c [1] and [5]). These data lie only approximately on the straight lines, for the value of parameter b does not amount exactly to 20 in all cases. It is possible to assume the probability that the kind of tree species, stand structure according to the number of trees (the silvicultural system), site quality, and age (in even-aged forests) influence the maguitude of parameters b and c. Should the influence of these factors on the magnitude of the parameters be examind (this has not yet been possible because of lack of a sufficient number of experimental plots), then it will parhaps be possible to assess from the amounts of these factors — in a given stand — the amounts of b and c. In this case it might be possible tk> design many such functional papers (fer several different b-amounts). and chose in a concrete instance the most convenient one. . |