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Altersstruktur und Wachstum anhand geworfener Bäume auf einer Windwurffläche im Waldreservat Bödmeren | Estimation of Age Structure and Growth Patterns on a Windthrow Area in the Bödmeren Forest Reserve

2001; Swiss Forestry Society; Volume: 152; Issue: 2 Linguagem: Inglês

10.3188/szf.2001.0061

2235-1469

Josef Gabriel, O. U. Bräker, Jean‐François Matter,

Botany and Plant Ecology Studies

The forest reserve Bödmeren near Muotathal in the canton of Schwyz, Switzerland, covers an area of 4.8 ha and is situated between 1200 and 1500 m a.s.l. It was established in 1971 and the terms of utilisation were drawn up in a contract with the proprietors of the ‹Oberalmeind Corporation›. The forest reserve serves as a multidisciplinary study area in which research of the natural succession without the influences of silvicultural treatment is conducted. In February 1990, a severe storm threw trees on an area of approx. 20 a, allowing a preliminary study to assess the age structure and growth patterns of small clusters of trees. The difference of the pith age of the 27 studied trees covered a range of 120 years, and contrary to expectations, the age difference of 24 trees was only 53 years. The trees were selected from 7 clusters and included all tree stages from the dominant tree to the suppressed tree. The b.h.d. ranged between 19.9 and 72.4 cm even though the age span within the cluster itself and amongst the clusters was generally small. The social position of the individual tree is usually reflected in the height as well as in the diameter growth pattern. The growth dynamics of a suppressed tree can change considerably during its lifetime: a tree was found to be the smallest in the cluster at the age of 20 years and then improved its position in the next 30 years to one of above average height and diameter. The average diameter increment at breast height culminated in the first decade and then decreased continuously. The height increment in the first two decades was restrained: the trees needed 16 years to attain a height of 1.3 m. After this period the individual height increment varied according to the competitional situation. Even though a cluster was dense, the dominated trees retained their vitality to an old age. The average height increment culminated at the age of 50 years.