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.本野外数据集（field dataset）可支持针对野火周边未受火烧区域内，由花旗松大小蠹（DFB, Dendroctonus pseudotsugae）引发的花旗松（DF, Pseudotsuga menziesii var. glauca）死亡时空动态的大范围分析（Andrus等人的研究已被录用待刊）。本数据集的研究目标为：对死亡花旗松个体开展调查，以验证其是否遭受花旗松大小蠹侵染，并对调查样地内可能助长花旗松大小蠹局部暴发的干扰因子（如根腐病、风倒）进行评估。 我们共采集了26处由花旗松大小蠹引发的花旗松死亡斑块的相关数据。为评估美国农业部（USDA）病虫害监测多边形区域内与花旗松死亡相关的致死因子（多边形选取方式详见研究论文），我们共布设了26个野外样地，每个样地内死亡花旗松数量均大于5株，且死亡时间均处于采样前5年内。针对每个死亡斑块，我们以其中心为原点设置半径15米（面积0.07公顷）的样地，以测量单木及林分尺度的相关属性，并评估与花旗松死亡相关的致死因子。 对于样地内胸径（DBH, Diameter at Breast Height）大于13厘米的林木，我们记录以下信息：树木种类、胸径、林木存活状态（活立、枯立）、红色针叶与绿色针叶占比，以及花旗松大小蠹活动的外部证据（如虫粪、侵入孔与羽化孔）。针对仅存枯黄色针叶的死亡花旗松个体，我们在胸高位置截取两块20厘米×20厘米的树皮样本，以检视其内树皮中花旗松大小蠹及次生性甲虫的繁殖坑道。次生性甲虫包括花旗松梢小蠹（Pseudohylesinus nebulosus）、花旗松刻切小蠹（Scolytus spp.）以及蛀干甲虫（如Phaenops drummondi与Buprestis lyrata）。我们估算了每块树皮样本被各昆虫类群侵染的比例，并对单木的两块样本结果取平均值。尽管观测到大量花旗松大小蠹侵染证据，但本次采样可能低估了韧皮部（phloem）样本中的花旗松大小蠹活动水平——因花旗松大小蠹更偏好侵染树干约3.6米以上的部位。 为识别样地内的干扰因子，我们对样地中心75米范围内的区域开展调查，以找寻可能推高花旗松大小蠹局部种群数量的近期干扰证据。干扰类型包括原木堆、带有花旗松大小蠹侵染证据的风倒花旗松（其死亡时间与近5年内受侵染的枯立花旗松一致）、野火（点烧火或未侦测野火）以及根腐病（如蜜环菌属Armillaria）。附带的readme.txt文件详细说明了两个数据集各字段的具体含义。