Norway spruce (Picea abies (L.) Karst.) is a major production tree species for the European wood industry. However, it is highly sensitive to bark stripping (BS) by red deer (Cervus elaphus L.), which causes large timber losses. Because the red deer population has increased over the last decades, a better understanding of the underlying causes driving BS is urgently needed. BS outbreaks are multifactorial: winter food shortage, local and regional deer abundance and stand properties (thermal and visual cover, and scarcity of herbaceous layers) have been found to drive BS rates. Although the influence of each of these factors is well studied, there is still no consensus on their relative contributions to BS or what mitigation strategy is best. In this study, we made use of a long-term, large-scale BS inventory (13 years over 2570 km2) to fill these gaps. We modeled winter and summer BS rates in response to the most explanatory variables, selected from a large set of environmental variables. Our results highlight the prevalence of deer abundance combined with high sensitivity of coniferous thickets and pronounced habitat selection by deer for these stands. Our findings show that the control of red deer populations is a key measure for reducing BS in Norway spruce stands.

中文翻译：

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减少云杉剥皮：需要控制马鹿种群

挪威云杉（Picea abies (L.) Karst.）是欧洲木材工业的主要生产树种。然而，它对马鹿 (Cervus elaphus L.) 的剥皮 (BS) 高度敏感，这会导致大量木材损失。由于马鹿种群在过去几十年中有所增加，因此迫切需要更好地了解导致 BS 的根本原因。BS 的爆发是多因素的：已发现冬季食物短缺、当地和区域鹿的丰度和林分特性（热和视觉覆盖以及草本层的稀缺）推动了 BS 率。尽管对这些因素的影响进行了深入研究，但对于它们对 BS 的相对贡献或最佳缓解策略仍未达成共识。在这项研究中，我们利用了一个长期的、大规模 BS 清单（13 年超过 2570 平方公里）来填补这些空白。我们模拟了冬季和夏季 BS 率，以响应从大量环境变量中选择的最具解释性的变量。我们的研究结果强调了鹿丰富的普遍性，加上针叶灌木丛的高敏感性和鹿对这些林分的明显栖息地选择。我们的研究结果表明，控制马鹿种群是减少挪威云杉林分 BS 的关键措施。