Leuphana University of Lüneburg, Institute of Ecology, Universitätsallee 1, 21335 Lüneburg, Germany.
Leuphana University of Lüneburg, Institute of Ecology, Universitätsallee 1, 21335 Lüneburg, Germany.
Sci Total Environ. 2018 Nov 15;642:1201-1208. doi: 10.1016/j.scitotenv.2018.06.065. Epub 2018 Jun 20.
Climate extremes are predicted to become more frequent and intense in future. Thus, understanding how trees respond to adverse climatic conditions is crucial for evaluating possible future changes in forest ecosystem functioning. Although much information about climate effects on the growth of temperate trees has been collected in recent decades, our understanding of the influence of forest management legacies on climate-growth relationships is still limited. We used individual tree-ring chronologies from managed and unmanaged European beech forests, located in the same growth district (i.e. with almost identical climatic and soil conditions), to examine how forest management legacies (recently managed with selection cutting, >20 years unmanaged, >50 years unmanaged) influence the radial growth of Fagus sylvatica during fluctuating climatic conditions. On average, trees in managed stands had higher radial growth rate than trees in unmanaged stands during the last two decades a 50%. However, the beech trees in the unmanaged stands were less sensitive to drought than those in the managed stands. This effect was most pronounced in the forest with longest management abandonment (>50 years), indicating that the drought sensitivity of mature beech trees is in these forests the lower, the longer the period since forest management cessation is. Management-mediated modifications in crown size and thus water demand are one likely cause of the observed higher climate sensitivity of beech in the managed stands. Our results indicate a possible trade-off between radial growth rate and drought tolerance of beech. This suggests that reducing stem density for maximizing the radial growth of target trees, as is common practice in managed forests, can increase the trees' drought sensitivity. In the prospect of climate change, more information on the impact of forest management practices on the climate-growth relationships of trees is urgently needed.
未来，极端气候预计将更加频繁和剧烈。因此，了解树木如何应对不利的气候条件对于评估未来森林生态系统功能可能发生的变化至关重要。尽管近几十年来收集了大量有关气候对温带树木生长影响的信息，但我们对森林管理遗产对气候-生长关系的影响的理解仍然有限。我们使用了来自管理和非管理的欧洲山毛榉林的单株树木年轮年表，这些森林位于同一生长区（即具有几乎相同的气候和土壤条件），以研究森林管理遗产（最近采用选择性采伐管理，20 多年未管理，50 多年未管理）如何影响山毛榉的径向生长在波动的气候条件下。平均而言，在过去的二十年中，管理林分中的树木比未管理林分中的树木具有更高的径向生长速度，高出 50%。然而，未管理林分中的山毛榉树对干旱的敏感性低于管理林分中的山毛榉树。这种影响在管理废弃时间最长的森林（>50 年）中最为明显，表明在这些森林中，成熟山毛榉树的干旱敏感性越低，森林管理停止的时间就越长。树冠大小和因此需水量的管理介导的改变是观察到管理林分中山毛榉对气候的敏感性更高的一个可能原因。我们的研究结果表明，山毛榉的径向生长速度和耐旱性之间可能存在权衡。这表明，为了最大化目标树木的径向生长而减少树干密度，如管理森林中的常见做法，可能会增加树木的干旱敏感性。在气候变化的前景下，迫切需要更多有关森林管理实践对树木气候-生长关系影响的信息。
