1.3 Carbon Storage by the UMBS forest. Aboveground woody biomass-carbon (C) production and net canopy photosynthesis during the 2001 and 2002 growing seasons. Vertical dashed line indicates the date on which 90 % of the total cumulative growth was achieved (2001 = day 226; 2002 = day 232) (Gough et al., in press).

These data suggest that poor agreement between annual biometric and meteorological C storage estimates (NEPB, NEPM) at UMBS is due, in part, to a lag between canopy photosynthesis and growth. Note that both leaf expansion and woody growth began prior to positive canopy photosynthesis. Also, more than 25 % of the annual carbon assimilated by the UMBS forest occured after growth had effectively stopped (orange dashed line). Thus, C assimilated late in the growing season appears to be applied to growth the following Spring. While this lag between photosynthesis and growth obscured agreement between annual biometric and meteorological estimates, 5-year estimates converged almost entirely (see previous slide).