@article{ref1,
title="Matching methods to quantify wildfire effects on forest carbon mass in the U.S.  Pacific Northwest",
journal="Ecological applications",
year="2020",
author="Woo, Hyeyoung and Eskelson, Bianca N. I. and Monleon, Vicente J.",
volume="ePub",
number="ePub",
pages="ePub-ePub",
abstract="Forest wildfires consume and redistribute carbon within forest carbon pools. Because  the incidence of wildfires is unpredictable, quantifying wildfire effects is  challenging due to the lack of pre-fire data or controls from experiments over a  large landscape. We explored a quasi-experimental method, propensity score matching,  to estimate wildfire effects on aboveground forest woody carbon mass in Washington  and Oregon, United States. Observational data, including national forest inventory  plot measurements and satellite imagery metrics, were utilized to obtain a control  set of unburned plots that are comparable to burned plots in terms of environmental  conditions as well as spatial locations. Three matching methods were implemented:  propensity score matching (PSM), spatial matching (SM), and distance-adjusted  propensity score matching (DAPSM). We investigated if propensity score matching with  and without spatial adjustment led to different outcomes in terms of 1) balance in  covariate distributions between burned and control plots, 2) mean carbon mass  obtained from the selected control plots compared to burned and all unburned plots,  and 3) estimates of wildfire effects by burn severity. We found that PSM and SM,  which use only the environmental covariate set or the spatial distance for  estimating propensity scores, respectively, did not appear to produce a comparable  set of control plots in terms of the estimated propensity scores and the outcomes of  mean carbon mass. DAPSM was the preferred method both in balancing the observed  covariates and in dealing with unobservable confounding variables through spatial  adjustment. The average wildfire effects estimated by DAPSM showed clear evidence of  redistribution of carbon among aboveground woody pools, from live to dead trees, but  the consumption of total woody carbon by wildfire was not substantial. Only moderate  burn severity led to significant reduction of total woody carbon mass across  Washington and Oregon forests (64% of control plots remained on average). This study  provides an applied example of a quasi-experimental approach to quantify the effects  of a natural disturbance for which experimental settings are unavailable. The study  results suggest that incorporating spatial information in addition to environmental  covariates would yield a comparable set of control plots for wildfire effects  quantification.<p /> <p>Language: en</p>",
language="en",
issn="1051-0761",
doi="10.1002/eap.2283",
url="http://dx.doi.org/10.1002/eap.2283"
}