It has been suggested that thinning trees and other fuel reduction practices aimed at reducing the probability of high-severity forest fire are consistent with efforts to keep carbon sequestered in terrestrial pools. By evaluating how fuel treatments, wildfire, and their interactions affect forest carbon stocks across a wide range of spatial and temporal scales, we conclude that this is almost never the case. Our analysis reveals high carbon losses associated with fuel treatment, only modest differences in the combustive losses associated with high-severity fire and the low-severity-fire fuel treatment is meant to encourage, and a low likelihood that treated forests will ever be exposed to fire. To identify the treatment levels which maximize protection from wildfire while minimizing the loss of forest carbon to the atmosphere, we present a simple model which tracks multiple forest carbon pools across entire landscapes for several decades and considers specifically: 1) the effect of fuel treatments on subsequent fire intensity and spread, 2) the carbon costs associated with treatment implementation, 3) fire probability and the effective lifespan of fuel treatments, and 4) the carbon losses associated with wildfire burning in treated and untreated stands.
Results/Conclusions
Initial application of this model to forest landscapes of eastern Oregon suggest that no level of fuel reduction results in increased carbon storage, however the risks of large-scale, high-intensity wildfire can be greatly reduced at only modest costs to forest carbon stocks.