DIGITALNA ARHIVA ŠUMARSKOG LISTA
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| ŠUMARSKI LIST 4-5/1953 str. 69 <-- 69 --> PDF |
From 2355 height measurements in 22 stands grown up on the first class site- quality (as indicated in the working plans) only one height curve was constructed. After having performed the anomorphosis of this height curve a non-linear d-scale resultet having the equation 8 = 1 . q> (d) (1 = scale modulus). Supposing that all height curves have the common eüuation h = a. straight lines going through origin with different slopes. On the graph of this kind every straight line representing height curve can be constructed if only one point is known (e. g. — d. b. h. of a mean-tree and its total height). The heights for the trees having d. b. h = 45 cm, and having the total volume (»Derbholz«) of 1,60; 1,70; 1,80; 2,60 and 2,70 m3 were computed from SCHWAPPACH´s volume tables (GRUNDER - SCHWAPPACH: Massentafeln zur Bestimmung des Holzgehaltes stehender Waldbäume und Waldbestände), because of not having on disposal local volume tables. Obtaining the folowing heights of 18,4, 19,7, 21,0, 31,4 and 31,7 meters, 12 straight lines were constructed (see graphs 1—4). On these graphs 1—4 it can also be observed how the individual height curves agree with this hypothesis.. By means of the heights read off from the graph and using SCHWAP- PACH´s volume tables — 12 »tariffs« — are worked out with d. b. h. as entry and giving volumes in cubic meters (m3) and h f in meters respectively. For finding out the number of »tariff« a nomogram is constructed in conformity with the principles of construction of graph No. 3 appeared in Šumarsk i lis t No. 2/1953. The nomogram (alignement chart) represents the equation h = a . cp (d) — or — log h =r log a + log (d) respectively. On the a - scale, instead of amounts of »a« corresponding to a certain »tariff«, the number of this »tariff« is written immediateli as scale-calibration. (In Croatian text the construcobtained by means of central projection of a d - scale. This d - scale is placed between h - scale and a - scale in this way, that from a point of the a - scale as a centre of projection, on h - scale a adjacent scale is obtained which represents the height-curve of corresponding «tariff« (see EMROVIĆ4). The employement of »tariff« is folowing: in a stand the diameters of all the trees are measured first, and than a mean tree is calculated (e. g. »Kreissflächentralstamm « or some other mean tree). For this mean tree about 10—30 height are to be measured in the stand, and the average is to be taken. The marks for the d. b. o. of the mean tree and corresponding height obtaiend as above — are connected with a straight line on the nomogram. Then it ought to be taken the tariff whole number which is nearest to the intersection of the above straight line with the a - scale (or tariff-number-scale respectively). The errors resulting from this approximation amount to a maximum of 2—3% and a greater precision is not needed at all (see LOETSCH8). The »tarif f s« of this kind when applied to local or regional conditions would give better results than those obtained by LAER, because of being prepared on the basis of local heights and especially when local form-factors have been taken into consideration. KAKO KUDZU PODNOSI POSOLICU Ing. O. Piškorić K K rajem 1950. godine Savezna uprava za unapređenje proizvodnje stavila je Srednjoj šumarskoj školi za krš u Splitu u zadatak ispitivanje odnosa kudzu-a (Dueraria hirsuta Set Z.) prema posolici. Za ovaj pokus dana je šema pokusa, u kojoj je pored ostalog stajalo i ovo: »Zalivanje treba vršiti prigodom sadnje i kasnije prema potrebi uvijek sa istom količinom vode odnosno mješavine. Pokus treba izvršiti s 6 X 2 biljke, koje će se zalivati slijedećim mješavinama obične i morske vode i to: |