The CO2 flux from coarse woody debris (RCWD) in a deciduous broad-leaved forest was measured
using chamber measurements. The relationships between RCWD
and environmental factors, such as temperature (T)
and the water content (θ) of the
coarse woody debris (CWD), were determined from long-term continuous
measurements. Measurements of the RCWD
of many CWD samples revealed relationships between RCWD
and CWD characteristics, such as wood density (ρ)
and diameter (D).
A field survey conducted in 2003 estimated the mass of
CWD as 9.30tC·ha-1, with snags amounting to 60% of the total CWD
mass. Scaling RCWD to the ecosystem
while considering environmental factors according to the type (snag or log) of
CWD and CWD characteristics, we estimated that the annual RCWD
in the forest was 0.50tC·ha-1·y-1 in 2003. This came to
13-19% of the total heterotrophic respiration in the forest. The mean annual
CWD input mass from 2000 to 2004 was 0.61tC·ha-1·y-1.
Therefore, 0.11tC·ha-1·y-1 were sequestered by CWD, which
amounted to 7% of the net ecosystem production (NEP)
in the forest. In a younger forest, it is difficult to assume that the CWD
input and decomposition are balanced, so the RCWD
and CWD input mass should be quantified to evaluate the forest carbon cycle and
NEP.
Author: M. Jomura, Y. Kominami, K. Tamai, T. Miyama, et al (majomura at mbox dot kyoto-inet dot or dot jp)
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