Die Wuchsdynamik der Küstendouglasie

Growth of coastal Douglas-fir in Canada and Germany

Weihenstephan

2003

18 Lit. Ang.

Artikel aus einer ZeitschriftUnselbständiges Werk

8316

200107036

A great number of growth models for coastal Douglas-fir have been developed in the Pacific Northwest of America. The newest models are used to compare the growth of Douglas-fir in the Pacific Northwest and Northwest Germany. The models are then applied to simulate different forest management options of Douglas-fir in Germany. The simulation results are validated against the Schenstrom plots, which form the oldest thinning experiment in the Pacific Northwest. The growth of Douglas-fir in the Northwest of Germany was represented by the managed stand yield table from Bergel. The results show a similar height growth in both regions and comparable stand statistics for site index 35 at breast height age 50. The simulation of different management options was then conducted by the distance dependent individual tree model TASS. Canadian silvicultural options are simulated and compared to the concept of the Bergel yield table. It can be derived, that in regard to final harvest the Canadian concepts are favourable, because of simular volumes, lower precommercial investment, larger diameters and higher stand stability. Furthermore low thinning reduces stand stability when affected by long term defoliation of more than 20 %. Nevertheless the low thinning concept allows the continuous supply with wood, which makes it more interesting for small scale forestry. In order to investigate the insufficient representation of individual height growth a model for the simulation of open-grown Douglas-fir was derived from the equations of TASS. Calculations showed, that annual height-growth can be related to the photosynthetic production per unit crown surface.