DIGITALNA ARHIVA ŠUMARSKOG LISTA
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| ŠUMARSKI LIST 1-2/2012 str. 71 <-- 71 --> PDF |
B. Matović, M. Koprivica, Z. Maunaga: PRIMJENAJEDINSTVENOG MODELAOBLIKADEBLASMREKE ... Šumarski list br. 1–2, CXXXVI (2012), 63-69 functions a1, a2, a3,...,.a15 are determined on the basis of available data, by applying multiple regression – equations (2), (3) and (4). In order to test the estimation of taper volume, on the material used for the development of generalized taper models of spruce trees by applying multiple regression, dual input volume tables were created. For that purpose Näslund and Schumacher-Hall functions were used – equations (6) and (7). This research confirms that Model 3 shows less accuracy in estimating the diameter along the taper and volume than Models 1 and 2, which besides using the diameter at breast height and tree height, also require using the stand quadratic mean diameter. However, such difference, from the aspect of practical use, is not important, so Model 3 that applies only the diameter at breast height and tree height (in fact, reduced to the level of dual input volume tables) can be successfully used in forestry practice. Obtained Model 3 is the superior substitute for conventional dual input volume tables, because besides the total volume it enables the volume estimation for particular parts of the standing tree, and also estimation of the diameter along the taper. Model 3 indirectly enables the calculation of tree heights with some diameters characteristic for forestry practice. Model 3, with all above mentioned practical possibilities, can be very simply used by applying one EXCEL application. Because of the dimensions of trees used for Model 3 design, it can be reliably used in practice for Norway spruce trees with diameters at breast height of 10 to 60 cm and height of 6 to 37 m. Key words:generalized model, taper, modified Brink’s function |