Development of a new branchiness index ASIX - A simple tool to describe branchiness in young deciduous forest stands

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 2520 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.