There is an increasing interest in restoring degraded forests, which occupy half of the forest areas. Among the forms of restoration, passive restoration, which involves the elimination of degrading factors and the free evolution of natural dynamics by applying minimal or no management, is gaining attention. Natural dynamics is difficult to predict due to the influence of multiple interacting factors such as climatic and edaphic conditions, composition and abundance of species, and the successional character of these species. Here, we study the natural dynamics of a mixed forest located in central Spain, which maintained an open forest structure, due to intensive use, until grazing and cutting were banned in the 1960s. The most frequent woody species in this forest are , , , , , and , with contrasting shade and drought tolerance. These species are common in temperate European deciduous forest and are found here near their southern distribution limit, except for . In order to analyze forest dynamics and composition, three inventories were carried out in 1994, 2005 and 2015. Our results show that, despite the Mediterranean influence, the natural dynamics of this forest has been mainly determined by different levels of shade tolerance. After the abandonment of grazing and cutting, expanded rapidly due to its lower shade tolerance, whereas after canopy closure and forest densification, shade-tolerant species gained ground, particularly , despite its lower drought and late-frost tolerance. If the current dynamics continue, will overtake the rest of the species, which will be relegated to sites with shallow soils and steep slopes. Simultaneously, all the multi-centennial beech trees, which are undergoing a rapid mortality and decline process, will disappear.

中文翻译：

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欧洲山毛榉橡树林后方边缘二十年的种群动态预示着其结构和组成的变化

人们对恢复占森林面积一半的退化森林越来越感兴趣。在恢复形式中，被动恢复正在引起人们的关注，它涉及消除退化因素并通过最少的管理或不进行管理来实现自然动态的自由演化。由于气候和土壤条件、物种组成和丰度以及这些物种的演替特征等多种相互作用因素的影响，自然动态很难预测。在这里，我们研究了位于西班牙中部的一片混交林的自然动态，由于密集使用，该林一直保持开放的森林结构，直到 20 世纪 60 年代禁止放牧和砍伐为止。这片森林中最常见的木本树种是、、、、、和，具有对比鲜明的遮荫性和耐旱性。这些物种在欧洲温带落叶林中很常见，并且在其南部分布范围附近发现，除了。为了分析森林动态和组成，我们于1994年、2005年和2015年进行了三次清查。我们的结果表明，尽管受到地中海的影响，该森林的自然动态主要由不同程度的耐荫性决定。在放弃放牧和砍伐后，由于耐荫性较低，耐荫树种迅速扩张，而在树冠关闭和森林致密化之后，耐荫树种得到了普及，特别是尽管其耐旱性和晚霜冻耐性较低。如果目前的动态继续下去，将超过其他物种，这些物种将被降级到土壤浅和斜坡陡峭的地方。与此同时，所有经历了快速死亡和衰退过程的百年山毛榉树都将消失。