Dendrogeomorphic analyses provide long and continuous chronologies of mass movements that are useful for the detection of trends related to climate change. Socio-environmental changes can, however, induce non-stationarities. This study addresses the following questions: (1) How does the evolution of forest cover induce non-stationarities in tree-ring based reconstructions of snow avalanche activity? (2) How are trends inherent to tree-ring approaches distinguishable from real fluctuations in avalanche activity? Using dendrogeomorphic techniques, we reconstructed snow avalanches in six adjacent paths in the French Alps. Results show two distinct trends in process activity between 1750 and 2016. In the southern paths, the frequency of snow avalanches increased sharply in the 1970s. The distribution of tree ages, as well as old topographic maps, allow an attribution of this trend to the destruction of large parts of the forest stand by a large snow avalanche in the 1910−20 s. This extreme event induced a sudden change in the capability of newly colonizing trees to record subsequent snow avalanches. In the northern paths, by contrast, progressive afforestation starting in the mid-19th century, as well as colonization of the release areas after World War II, resulted in a strong reduction in snow avalanche activity since the 1930s. Even if global warming remains a possible additional driver of snow avalanche activity at the study sites, the rural exodus and the abatement of pastoral practices during the 19th and 20th centuries are the main explanations for the observed trends in process activity. Results also illustrate a need to clarify the complex interrelations among forest evolution, global warming, social practices, and the process activity itself when interpreting trends in mass movements.

树状形态分析提供了长时间连续的质量运动时序表，可用于检测与气候变化有关的趋势。但是，社会环境的变化可能导致不稳定。这项研究解决了以下问题：（1）森林覆盖的演变如何在基于树环的雪崩活动重建中引起非平稳性？（2）树木年轮方法固有的趋势如何与雪崩活动的实际波动区分开来？使用树状地貌技术，我们在法国阿尔卑斯山的六个相邻路径中重建了雪崩。结果表明，在1750年至2016年之间，过程活动存在两个明显的趋势。在南部路径中，雪崩的发生频率在1970年代急剧增加。树木年龄的分布以及旧的地形图，允许将此趋势归因于1910-20年代大雪崩造成的大部分森林林分的破坏。这次极端事件导致新定居的树木记录随后的雪崩的能力突然改变。相反，在北部道路上，始于19世纪中叶的逐步绿化以及第二次世界大战后对释放区的殖民化导致自1930年代以来雪崩活动大大减少。即使全球变暖仍是研究地点雪崩活动的一个可能的额外驱动因素，在19世纪和20世纪期间农村的外流和牧民活动的减少仍是观察到的过程活动趋势的主要解释。结果还表明，有必要澄清森林进化之间的复杂相互关系，