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Recent Work -- presented as a poster at the 2001 IUFRO Canopy Processes Conference

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We have conducted tests of a highly parameterized version of Biome-BGC at the Metolius young and old pine flux sites. Biome-BGC estimates of major carbon flux components at the pine flux sites agreed with budget-based observations to within +/- 20%, with larger differences for NEP and several storage terms.
	Metolius Old Flux Site (left) and soil flux measurements at HJ Andrews (right)
Simulations showed the period of regrowth required to replace carbon lost during and after a stand-replacing fire (old pine) or a clearcut (young pine) to be 50 to 100 years, and a shift from net carbon source to net sink 10 to 20 years after disturbance at both sites.
	The Biome-BGC estimates of daily GEP were generally higher than flux data suggest in the dry summers, and lower in spring and fall during the rainy season (Law et al. in press).
LAI and NPP mapped at the 1 km scale in the Metolius area.
We applied Biome-BGC to 5 x 5 km areas at Metolius (MR), HJ Andrews (HJ), and Wind River (WR), and found that predicted NEP ranged from -200 to 500 g C/m2/yr, with highest values in young stands at HJ Andrews. Our regional-scale approach will be a major advance beyond site-based simulations, bridging the gap to global applications.
Simulation of the effects of a clearcut harvest and fire and a windthrow on carbon stores (left) and NEP (right), based on productivity and decay data collected in a chronosequence of Douglas-fir/hemlock forests at Wind River, Washington. The figures show the range of values expected given the range of variation in the parameters measured.
Wind River chronosequence. Productivity and decay measurements (NEP = NPP - Rh)

References:
Law, B.E., P. Thornton, J. Irvine, S. Van Tuyl, P. Anthoni. 2001. Carbon storage and fluxes in ponderosa pine forests at different developmental stages. Global Change Biology. In press.