Timber interests target coastal temperate rainforests, and within them stands composed of large trees potentially selected by American black bears (Ursus americanus) for denning. We identified the location of 75 black bear dens (used ≥14 days) in an intensively logged area on Prince of Wales Island, Alaska, USA. We ground-visited a subset (n = 43) of these sites to measure the diameter of living trees and woody structures used by black bears for denning. We contrasted dens with random trees available in the study area in a series of models to characterize black bear den selection. All but 1 of 43 ground-visited dens were located within woody structures, and all but 2 of these structures were >1 m diameter at breast height (dbh). We built resource selection functions (RSFs) to investigate black bear den selection across a range of spatial scales, though estimated selection was generally scale invariant. Black bears strongly selected large-diameter woody structures (dead or alive) as dens at the home-range scale, with the estimated relative strength of selection (RSS) for a 2-m-diameter tree approximately 166 times that of a 1-m-diameter tree. The estimated RSS of logged forest was unexpectedly greater (2.75 times) than that of the remaining commercially valuable old-growth forest. Selection for den structures within stumps in previously logged stands suggests features of the woody structure may be of greater importance to black bears selecting dens than attributes of the surrounding forest. There was no observed correlation between bear den selection and second-growth age, indicating that stumps may persist as suitable dens well after logging. Because denning is an important part of their life history and the denning structures used by black bears on Prince of Wales Island will eventually decay, retaining habitat value for bears in areas intensively managed for timber harvest requires strategies to recruit very large, old trees throughout the landscape. © 2021 The Wildlife Society.

中文翻译：

---

黑熊为阿拉斯加东南部的巢穴选择大型木质结构

木材利益的目标是沿海温带热带雨林，其中有可能被美国黑熊 ( Ursus americanus ) 选择用于栖息的大树。我们在美国阿拉斯加州威尔士亲王岛的密集采伐区确定了 75 个黑熊窝点（使用时间≥14 天）的位置。我们地面访问了一个子集（n = 43) 这些地点用于测量黑熊用于筑巢的活树和木结构的直径。我们在一系列模型中将巢穴与研究区域中可用的随机树进行了对比，以表征黑熊巢穴的选择。除了 43 个地面访问过的巢穴中的 1 个之外，所有的巢穴都位于木质结构内，并且这些结构中的所有除了 2 个在胸高 (dbh) 处的直径 > 1 m。我们构建了资源选择函数 (RSF) 来研究一系列空间尺度上的黑熊巢穴选择，尽管估计的选择通常是尺度不变的。黑熊在家庭范围内强烈选择大直径木本结构（死的或活的）作为巢穴，2 米直径树的估计相对选择强度 (RSS) 大约是 1 米树的 166 倍-直径树。砍伐森林的估计 RSS 出乎意料地大于（2.75 倍）剩余的具有商业价值的原始森林。在先前砍伐的林分中选择树桩内的巢穴结构表明，对于黑熊选择巢穴而言，木本结构的特征可能比周围森林的属性更重要。没有观察到熊窝选择与第二次生长年龄之间存在相关性，这表明树桩在伐木后可能会继续作为合适的窝点。由于窝棚是它们生活史的重要组成部分，而威尔士亲王岛上黑熊使用的窝棚结构最终会腐烂，因此在为木材采伐而集中管理的地区保留黑熊的栖息地价值需要采取策略在整个地区招募非常大的老树景观。© 2021 野生动物协会。