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Estimating 1990 carbon stocks and fluxes in California. J.S. Fried and X Zhou, PNW-FIA. Manuscript in preparation for
USDA Forest Service, Pacific Northwest Research Station, General Technical Report. 14 Nov. 2007
Forest inventory-based estimation of carbon stocks and flux in
California forests in 1990
A draft PNW General Technical Report
by
Jeremy Fried and Xiaoping Zhou
14 November, 2007
Introduction
The US Forest Service, Pacific Northwest Research Station, Forest Inventory and Analysis
Program (PNW-FIA) was officially asked on October 15th by the U.S. Forest Service Region 5
and Pacific Southwest Research Station to prepare an estimate of circa 1990 carbon stocks and
stock change (often referenced hereafter as flux) in California forests by November 1, 2007 in
support of greenhouse gas inventory efforts by the State of California pursuant to AB32, a State
law that mandates a return to 1990 greenhouse gas emissions by 2020, with further reductions in
emissions thereafter. The California Air Resources Board has been engaged in creating a
greenhouse gas inventory for every sector of the state’s economy. As perhaps the only sector
with the potential for negative net emissions (i.e., sequestration of carbon in standing trees, long-
lived forest products, and as biomass-generated energy that substitutes for fossil fuel-generated
energy), forestry is a particularly important sector in this accounting effort.
In addition to the sector-wide and owner class-specific tracking of sequestration of carbon in
forest biomass, key questions concerning greenhouse gases and climate change will depend on
the georeferenced network of over 6800 forested PNW-FIA plots in California. The occurrence
of fire, insect and disease events is dependent on both ownership and location with respect to
stressors. In addition to changing the carbon flux, these events can have substantial impacts on
other greenhouse gas emissions such as methane, nitrous oxide, biogenic hydrocarbons, and the
precurso