Integrated, Observation-Based Carbon Monitoring for Wooded Lands of Washington, Oregon, and California.

Although forests and woodlands are important reservoirs of carbon,  the net carbon flux at from wooded lands at regional scales is highly constrained by disturbance and subsequent regrowth processes.  Carbon dynamics in forests thus require frequent observation of forest condition, mortality, and growth processes. Although periodic ground- and satellite-based measures of biomass and of stand-replacing disturbance have long existed, limitations of both prevent full characterization of carbon dynamics at appropriate scales. Our project integrates new tools to link these data to address a range of critical and hitherto unanswerable carbon issues, focusing on forests in the states of Washington, Oregon and California.

Here, we report on the first year of our project, where we are testing full integration of forest plot data (FIA;  Forest Inventory and Analysis), environmental data, satellite-imagery, and aircraft-based lidar acquisitions to create a full assessment of carbon dynamics from 1990 to 2010.  Using our first focal area in the West Cascades province in Oregon and northern California, we show how change in forest carbon stocks has varied as a function of both forest management changes (particularly changes in federal and state land management) and natural disturbance regimes (with increased impacts of forest pest/insects and fires over time), and compare cumulative impacts of natural vs. anthropogenic forest disturbance on forest carbon at regional scales.  We also document how relative uncertainties in our estimates caused by methodological choices vary with age of forest and general ecoregion type, and compare relative importance of image, statistical, and allometric equation in those uncertainty estimates.