Effects of log length on Polygraphus proximus attack

Polygraphus proximus Blandford (Coleoptera: Curculionidae: Scolytinae), a non-aggressive bark beetle, has caused mortality of Abies spp. in Western Siberia, Central Asia, European Russia as well as Japan. Removing dead trees (i.e. salvage logging) and thinning stands are considered one of the best practices to reduce the risk of bark beetle outbreaks. However, salvaging or removing dead and thinned trees requires significant effort. Thus, to determine whether cutting trees shorter would reduce P. proximus infestation, we exposed A. sachalinensis logs of various lengths on the ground in a forest stand. The attack density of P. proximus significantly decreased with shorter log lengths. It can be concluded that cutting into short logs and leaving them on the ground are effective practices to reduce the chance of P. proximus outbreaks after natural disturbances and thinning., , , # Effects of log length on *Polygrapus* *proximus* attack This dataset comprises one \"G.csv\" file. ## Description of the Data and file structure * Description: This file shows the result of the experiments to determine the effects of log length (10 cm, 20 cm, 40 cm, 60 cm, and 80cm) on the attack density of the bark beetle *Polygraphus proximus*. * Variables: * \"tree\": The IDs of the trees from which logs were obtained. * \"logid\": The IDs of the logs (bolts) used in the experiments. * \"l\": length of the logs (cm). * \"c\": The circumferences (cm) of the logs (= circumferences at both cut-ends and the middle/3). * \"area\": length of the logs (l) * The circumferences of the logs (c). * \"gallery\": Number of mother galleries under the bark. Same as the number of entrance holes by *Polygraphus proximus.* * \"dens\": Density of the entrance holes (= \"gallery\" / \"area\").近缘多毛小蠹（Polygraphus proximus Blandford，鞘翅目Coleoptera：象甲科Curculionidae：小蠹亚科Scolytinae）是一种非攻击性树皮小蠹，曾在西西伯利亚、中亚、俄罗斯欧洲部分及日本引发冷杉属（Abies spp.）植株死亡。救灾性采伐（即移除枯木）与林分疏伐被视为降低树皮小蠹暴发风险的最优措施之一。然而，救灾性采伐或移除疏伐产生的枯木需投入大量人力与物力。为此，为探究缩短木段长度是否能减轻近缘多毛小蠹的侵染危害，我们在林分的地面上放置了不同长度的萨哈林冷杉（Abies sachalinensis）木段。实验结果显示，近缘多毛小蠹的入侵密度随木段长度缩短而显著降低。由此可得出结论：将木段截短后留置于地面，是降低自然扰动与疏伐后近缘多毛小蠹暴发概率的有效措施。 # 木段长度对近缘多毛小蠹（Polygraphus proximus）入侵的影响 本数据集包含一个名为"G.csv"的文件。 ## 数据与文件结构说明 * 数据说明：该文件呈现了旨在探究木段长度（10 cm、20 cm、40 cm、60 cm与80 cm）对树皮小蠹近缘多毛小蠹入侵密度影响的实验结果。 * 变量说明： * "tree"：用于制取木段的母树编号。 * "logid"：实验所用木段（原木段）的编号。 * "l"：木段长度（单位：cm）。 * "c"：木段周长（单位：cm），即木段两端切面与中段的周长。 * "area"：木段表面积，计算方式为木段长度（l）与木段周长（c）的乘积。 * "gallery"：树皮下母坑道的数量，与近缘多毛小蠹的入侵孔数量一致。 * "dens"：入侵孔密度，计算公式为"gallery"除以"area"。