2.2 Ecosystem respiration at UMBS. Daily respiratory C loss in 2001 from soil (Rs), leaves (R l), boles (Rw), and their sum, ecosystem respiration, (R-sigma) for UMBS (upper panel). The percentage contribution of Rs, Rl, and Rw to R-sigma is shown in the lower panel (Curtis et al., New Phytologist, 2005).

From 1999-2003, Rs was the dominant component of R-sigma, contributing as much as 73 % of the total flux (1999), with a five year mean of 71 %. Leaf respiration contributed on average 18 % and Rw 11 % of R-sigma. Mean annual ecosystem respiration in 2001 was typical of other years, when annual respiratory C losses were 14.1 Mg C ha-2 y-1.