DIGITALNA ARHIVA ŠUMARSKOG LISTA
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| ŠUMARSKI LIST 11-12/1960 str. 13 <-- 13 --> PDF |
se na taj način vremenom sakupila veća količina — na isti način — izmjerenih modernih stabala, te bi se podaci iz različitih lokaliteta mogli upoređivati, kumulirati i t. d. Ovako kake- smo dosada radili t. j . kada je svaki autor mjerio na svoj način i to samo one podatke koji su bili interesantni za konkretni zadatak, velika su sredstva utrošena, a samo uz mala dodatna sredstva moglo se na taj način već dosada dobiti značajan broj modelnih stabala za izradu domaćih tablica. LITERATURA [1] Schuber g K.: Formzahlen und Massentafeln fiir die Weisstanne, Berlin 1891. [2] Tordon y M.: Kubične skrižaljke za stojeću prodaju ielovih stabala. Šumarski list br. 3, 1897. [3] Schumache r F. X.-Hall F. D. S.: Logaritmic Expression of Timber-tree Volume. Journal of Agr. Res.. Vol. 47. Washington 1933. [4] Milojkovi ć D.: Istraživanje oblika i zapremine jele u zaštićenim šumama planine Tare. Izdanje Zavoda za zaštitu prirode i naučno proučavanje prirodnih retkosti NR Srbije, Beograd 1953. DOUBLE-ENTRY VOLUME TABLES FOR SILVER FIR IN GORSKI KOTAR S U M M A R Y The German double-entry volume tables for Silver Fir — Abies alba (See Schuberg [1]) give poor results in determining the timber volume in the area of Gorski Kotar (= mountaineous region in the \vestern part of Croatia — between Zagreb and Rijeka). In this area the most important influence is played by the parent rock, and on the underlying silicate rock there grow predominatly the even-aged forests while on the calcareous parent rock the seleetion forests. Schuberg´s Tables yield for the trees from the silicate substratum (even-aged forests) too small stem volumes, while for the trees from the calcareous substratum too large ones. On the basis of 424 sample trees from the silicate subsoil. and 126 trees from the calcareous were prepared tables separately for the silicate und separately for the calcareous subsoil (See Tables 4 and 5). The adjustment of volume was carried out by the method of least squares using the Schumacher-Hall´s formula (See Schumacher-Hall f2]). The parameters of the adjustment equations are compared with the parameters calculated from Schuberg´s Tables (»Derbholz«) for different ages (see Table 2). The errors of parameters Oh and or are relatively high which means that the preparation of tables requires a greater number of data (sample trees). The volume (and consequently also the form factors) of trees from the silicate substratum (even-aged forest)are larger than those ones from the calcareous substratum (seleetion forest) which is understandable (See Table3). It is interesting that the magnitude of parameter c is greater than 1. which means that the form factor inereases when the height inereases {on condition that the d. b. h. is the same). This fact is corroborated also by the analysis of the material taken from the silicate subsoil, vvhich shows that the form quotient amounts approximately to q2 = 0´720 — 0´025 d — 0´035 h (d = diameter at breast height in cm., h = total height in m., q = form quotient i. e. the ratio between the diameter in total mid-height and d. b. h.), and — on the basis of the known high positive correlation betwecn the form quotient and form factor — it is possible to conelude that the form factor f´ ehanges in a similar manner. The volume tables (See Tables 4 and 5) are of temporary eharacter because they are unreliable owing to the too small number of data which served as their basis. Table 1 yields the data concerning the number of stems having served as the basis in the construetion of volume tables. Data are grouped aceording to the diame |