tailieunhanh - Báo cáo lâm nghiệp: "Value production of poplar clones'

Tuyển tập những bài báo cáo nghiên cứu khoa học hay nhất được đăng trên tạp chí JOURNAL OF FOREST SCIENCE đề tài: Value production of poplar clones. | JOURNAL OF FOREST SCIENCE 54 2008 6 237-244 Value production of poplar clones R. Petrás J. Mecko V. Nociar National Forest Centre - Forest Research Institute Zvolen Zvolen Slovakia ABSTRACT The results of research on the value production of the stands of poplar clones Robusta and I-214 carried out in Slovakia are presented. Models of value yield tables were constructed separately for each clone. The models simulate gross and net financial yield of wood production in dependence on the site index and age of stand. They were constructed on the basis of the models of assortment yield tables timber prices according to assortments and the models of own costs of timber felling and processing. The clone I-214 produces a faster and higher proportion of thicker assortments of average and below-average quality and therefore it has the higher value production at a younger age only. Robusta produces smaller diameter but higher quality assortments and has the higher value production only at an older age. The site index of the stand is the most important factor in the value production of poplar clones. Differences in the production between site indexes are much greater than between the clones. Keywords poplar clones value production gross and net financial yield value yield tables Quality production of wood raw materials with maximal use of natural factors and minimum costs of human labour is the main aim of forest production with regulated management it means forest cultivation in its whole production framework. Knowledge of the value production of forest stands exists on two levels according to known literary sources. The first level is the individual financial valuation of the stocks of concrete stands with their mensurational characteristics and the second level represents knowledge in this field for the lifelong development of forest stands and their total production in the form of value yield tables. Gross and net financial yield may be expressed similarly like traditional