Can the characteristics of the crown influence the stability of poplar trees?

Abstract

The stability of trees represented a concern for the specialists in forestry because the windthrows produce large damages and big economic losses. On the other hand, the trees located in public areas, which are affected by the wind could produce injuries to the people and also could prejudice the goods. Because the risk of falling is very big the case of old trees with a large crown is important to know the quality of the wood inside the tree and some growth characteristics which can influence the stability. As the crown is the most developed aerial part of the trees, its surface and volume can represent decisive factors in maintaining the tree's stability. Taking into account the importance of trees in public areas like parks, gardens and street alignments, the aim of the study is to evaluate how the growth characteristics of the crown could affect the stability of poplar trees located along an alignment. The measurements were made for 163 black poplar (Populus nigra L.) trees. Poplar is one of the most representative species used for the street alignments in Romania, both in cities and along the main public roads. The characteristics of the crown (height and four radii of the lower part of the crown) were measured in the field and its shape was evaluated. Moreover, the principal dimensions of the trees (height and diameter at the breast height) were measured. Because the risk of accident is caused also by the big branches which could fall from the large trees some evaluations regarding the presence of dry branches and other visible defects were made.