Event Website

http://www.nafew2009.org/

Start Date

25-6-2009 9:00 AM

End Date

25-6-2009 9:20 AM

Description

Currently increasing efforts are made to manage CWD as a habitat component and a carbon store in forest ecosystems. For this a basic understanding of patterns and rates of dead wood decomposition in different forests is crucial. The decomposition rate of CWD is mainly dependent on climatic (wood temperature, wood moisture) and substrate specific (tree species, decay stage, diameter) variables. Here, we analysed the influence of these factors using a combined approach. 1) We assessed the decay rate of Fagus sylvatica, Picea abies and Pinus sylvestris in three diameter classes (10-20 cm, 20-40 cm, >40 cm) along a climatic/altitudinal gradient (temperature, precipitation) retrospectively in the field. 2) We analysed under controlled conditions the effect of varying wood temperature (5, 10 and 20 ∞C) and moisture (three steps) on the current respirational carbon loss of CWD of Fagus sylvatica, Picea abies and Pinus sylvestris in relation to decay stage (1, 3 and 5 related to a 5-class decay classification system). 3) We measured CWD respiration continuously over one year in the field on a F. sylvatica and P. abies log and analysed the effect of substrate specific (tree species, decay stage, diameter), micro-climatic (wood moisture and temperature) as well as environmental variables (ground contact or suspended). A highly significant effect of wood temperature and moisture on respirational carbon loss regardless of decay stage was observed under controlled conditions as well as in the field. In both cases the respirational C loss of F. sylvatica CWD was about twice that of P. abies. Suggestions will be provided, how C loss from CWD might be represented in decomposition and ecosystem C models.

 
Jun 25th, 9:00 AM Jun 25th, 9:20 AM

What Drives Decomposition Rates of Coarse Woody Debris (CWD)?

Currently increasing efforts are made to manage CWD as a habitat component and a carbon store in forest ecosystems. For this a basic understanding of patterns and rates of dead wood decomposition in different forests is crucial. The decomposition rate of CWD is mainly dependent on climatic (wood temperature, wood moisture) and substrate specific (tree species, decay stage, diameter) variables. Here, we analysed the influence of these factors using a combined approach. 1) We assessed the decay rate of Fagus sylvatica, Picea abies and Pinus sylvestris in three diameter classes (10-20 cm, 20-40 cm, >40 cm) along a climatic/altitudinal gradient (temperature, precipitation) retrospectively in the field. 2) We analysed under controlled conditions the effect of varying wood temperature (5, 10 and 20 ∞C) and moisture (three steps) on the current respirational carbon loss of CWD of Fagus sylvatica, Picea abies and Pinus sylvestris in relation to decay stage (1, 3 and 5 related to a 5-class decay classification system). 3) We measured CWD respiration continuously over one year in the field on a F. sylvatica and P. abies log and analysed the effect of substrate specific (tree species, decay stage, diameter), micro-climatic (wood moisture and temperature) as well as environmental variables (ground contact or suspended). A highly significant effect of wood temperature and moisture on respirational carbon loss regardless of decay stage was observed under controlled conditions as well as in the field. In both cases the respirational C loss of F. sylvatica CWD was about twice that of P. abies. Suggestions will be provided, how C loss from CWD might be represented in decomposition and ecosystem C models.

http://digitalcommons.usu.edu/nafecology/sessions/forest_detritus/7