tailieunhanh - Báo cáo lâm nghiệp: "Variation of conducting area in stems of European larch (Larix decidua) growing in fresh mixed coniferous forest and fresh mixed forest sites"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí lâm nghiệp đề tài: Variation of conducting area in stems of European larch (Larix decidua) growing in fresh mixed coniferous forest and fresh mixed forest sites. | JOURNAL OF FOREST SCIENCE 56 2010 1 18-27 Variation of conducting area in stems of European larch Larix decidua growing in fresh mixed coniferous forest and fresh mixed forest sites M. Nawrot1 M. Jakubowski1 W. Pazdrowski1 K. Kazmierczak2 M. Szymanski1 -Department of Forest Utilization Poznan University of Life Sciences Poznan Poland Department of Forest Management Institute of Dendrometry and Forest Productivity Science Poznan University of Life Sciences Poznan Poland ABSTRACT The paper presents an attempt to determine conducting area CA relative conducting area and mean ring conducting area CAar on discs cut at breast height from stems of larch trees growing in fresh mixed coniferous forest and fresh mixed forest sites representing four age classes and the main crop according to Kraft s classification. The value of CA increases with an improvement of the social class of tree position in the community while no such dependences were found for the value of . The parameter CAar except for one case in age class IV in the fresh mixed coniferous forest site increases with an improvement of the position a tree takes in the community and differentiates more markedly under the conditions of fresh mixed forest sites. Relative conducting area decreases markedly with an increase in the age of trees which is confirmed by high values of the coefficient of determination. Moreover the significance of differences between individual trees in the main crop according to Kraft and forest site types was tested in terms of the values of CAar. Calculated values may be used to describe the relationships between conducting area and the size of the assimilating organ more precisely than the total sapwood zone. Keywords conducting area European larch mean ring conducting area relative conducting area social class of tree position The structure and properties of wood are a consequence of genetic environmental and anthropogenic factors acting during the formation of wood .