Fig. 4: The climatic components of SORD most impacted by wildfire occurrence, separated by wildfire history, and aggregated across species.
From: Forest fires and climate-induced tree range shifts in the western US
The plot includes results for all species that share the direction of a statistically significant difference (two-sided t-test, p < 0.05) between seedling-only (n = 1806) and tree-plus-seedling (n = 5654) populations in unburned plots. The species included are: Chrysolepis chrysophylla, Pinus ponderosa, Pseudotsuga menziesii, Quercus chrysolepis, and Quercus kelloggii. Boxplots include the median line, a box denoting the interquartile range, and whiskers showing values ± 1.5x the interquartile range. This figure demonstrates that while these five species show a trend in unburned seedling-only plots towards lower mean temperature of the warmest month and higher mean summer precipitation, the difference in burned plots is greater (p < 0.01). Climate variables were standardized by dividing the values by their root-mean-squares. Multiple linear regression was used to quantify the difference in SORDs between burned and unburned samples. Supplementary Fig. 3 shows this analysis across the full suite of climate variables, including those where the difference between the SORDs of burned and unburned samples were not statistically significant. Source data are provided as a Source Data file.
