Data from: Limited tree mortality in unburned areas linked to bark beetle spillover from wildfires

This field dataset supports a broader scale analysis of the spatiotemporal progression of DF tree mortality from DFB in unburned areas surrounding wildfires (Andrus et al. accepted). The goal of the field dataset was to assess individual dead Douglas-fir trees (DF, Pseudotsuga menziesii var. glauca) for evidence of attack by Douglas-fir beetle (DFB, Dendroctonus pseudotsugae) and assess sites for disturbance agents (e.g., root disease, blowdown) that may have supported localized irruptions of DFB. We collected data in 26 individual patches of DF mortality from DFB. To assess the mortality agents associated with DF mortality in USDA insect and disease polygons (see research paper for polygon selection), we sampled 26 field plots with > 5 dead DF trees and dead DF trees died within 5 years of sampling. For each plot, we established a 15 m radius plot (0.07 ha) at the center of each mortality patch to measure tree- and stand-scale attributes and assess mortality agents associated with DF mortality. For each tree (> 13 cm DBH) in the plot, we recorded the following: tree species, DBH, tree status (live, dead), percent red and green needles, and external evidence of DFB activity (e.g., frass, entrance and exit holes). For dead DF trees only (no green needles), we removed two sections of bark (20 cm tall by 20 cm wide) at breast height to examine the inner bark for DFB and secondary beetle reproductive galleries. Secondary beetles included Douglas-fir pole beetle (Pseudohylesinus nebulosus), Douglas-fir engraver beetles (Scolytus spp.), and wood boring beetles (e.g., Phaenops drummondi and Buprestis lyrata). We estimated the total proportion of the panel attacked by each insect species/group and averaged the two panels for each tree. Even though we observed substantial evidence of DFB, sampling likely underestimated DFB activity in the phloem panels as DFBs preferentially attack portions of the tree bole higher than ~3.6 m. To identify site disturbance agents, we surveyed areas within 75 m of plot center for evidence recent disturbance that may elevate localized populations of DFB. Disturbances included log decks, blown down DF trees with evidence of DFB that were of similar time since mortality as standing dead DF trees with DFB (last 5 years only), fire (spot fires or undetected fires), and root disease (e.g., Armillaria).

The attached readme.txt provides detailed descriptions for each column in both datasets.