tailieunhanh - Báo cáo khoa học: "Development of a new branchiness index ASIX – A simple tool to describe branchiness in young deciduous forest stand"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Development of a new branchiness index ASIX – A simple tool to describe branchiness in young deciduous forest stands. | 811 Ann. For. Sci. 57 2000 811-818 INRA EDP Sciences Original article Development of a new branchiness index Asix -A simple tool to describe branchiness in young deciduous forest stands Gerhard Struck and Achim Dohrenbusch Institute of Silviculture Department I Silviculture of the Temperate Zones and Forest Ecology University of Gottingen Busgenweg 1 37077 Gottingen Germany Received 6 September 1999 accepted 24 March 2000 Abstract - Description of young tree s quality is difficult in particular there is no adequate and easy applied method to describe branchiness. The following contribution describes the development of a new index to estimate the branch s diameter influence on tree quality. On the base of the measurement of 2 520 young oak trees 22 years old the branchiness index Asix was created as the ratio between the branch of the largest diameter and the tree s diameter at breast height DBH . The idea was that a same diameter of branches is worse for small trees than for bigger ones. In a very wide range of plant densities no influences of the different initial densities on the Asix values were found. Trees in wider plantations with a higher branch diameter had as good Asix-values than trees in denser plantations with a lower branch diameter. But however an influence of different site conditions on the Asix was noticed. Aisx was better within better site conditions compared to worse site conditions. It is concluded that the description of branchiness using this ratio is better than the use of absolute diameter values. Asix integrates the stands growth potential in terms of DBH. The use of this index avoids the overestimation of branch-thickness for trees with a high growth potential. Due to a lack of literature dealing with branch-ratios there are no comparisons to other indices in the discussion. branchiness index stand density deciduous forests quality Quercus Résumé - Développement d un nouvel indice de branchaison ASIX un outil simple pour décrire la .