Swiss Federal Research Institute WSL, Zurcherstrasse 111, 8903 Birmensdorf, Switzerland.
Tree Physiol. 2012 Feb;32(2):178-87. doi: 10.1093/treephys/tps004. Epub 2012 Feb 23.
Climate change is challenging forestry management and practices. Among other things, tree species with the ability to cope with more extreme climate conditions have to be identified. However, while environmental factors may severely limit tree growth or even cause tree death, assessing a tree species' potential for surviving future aggravated environmental conditions is rather demanding. The aim of this study was to find a tree-ring-based method suitable for identifying very drought-tolerant species, particularly potential substitute species for Scots pine (Pinus sylvestris L.) in Valais. In this inner-Alpine valley, Scots pine used to be the dominating species for dry forests, but today it suffers from high drought-induced mortality. We investigate the growth response of two native tree species, Scots pine and European larch (Larix decidua Mill.), and two non-native species, black pine (Pinus nigra Arnold) and Douglas fir (Pseudotsuga menziesii Mirb. var. menziesii), to drought. This involved analysing how the radial increment of these species responded to increasing water shortage (abandonment of irrigation) and to increasingly frequent drought years. Black pine and Douglas fir are able to cope with drought better than Scots pine and larch, as they show relatively high radial growth even after irrigation has been stopped and a plastic growth response to drought years. European larch does not seem to be able to cope with these dry conditions as it lacks the ability to recover from drought years. The analysis of trees' short-term response to extreme climate events seems to be the most promising and suitable method for detecting how tolerant a tree species is towards drought. However, combining all the methods used in this study provides a complete picture of how water shortage could limit species.
气候变化正在挑战林业管理和实践。除其他事项外，必须确定具有应对更极端气候条件能力的树种。然而，虽然环境因素可能严重限制树木生长，甚至导致树木死亡，但评估树种在未来加剧的环境条件下生存的潜力是相当困难的。本研究的目的是找到一种基于树木年轮的方法，该方法适用于识别非常耐旱的树种，特别是替代瓦莱州苏格兰松（Pinus sylvestris L.）的潜在替代树种。在这个阿尔卑斯山内部的山谷中，苏格兰松曾经是干旱森林的主要树种，但如今它因高干旱导致的死亡率而遭受严重影响。我们研究了两种本地树种（苏格兰松和欧洲落叶松（Larix decidua Mill.））以及两种非本地树种（黑松（Pinus nigra Arnold）和花旗松（Pseudotsuga menziesii Mirb. var. menziesii））对干旱的生长反应。这涉及分析这些物种的径向增量如何响应日益增加的水分短缺（放弃灌溉）和日益频繁的干旱年份。黑松和花旗松比苏格兰松和落叶松更能应对干旱，因为即使在灌溉停止后，它们的径向生长仍然相对较高，并且对干旱年份具有弹性生长反应。欧洲落叶松似乎无法应对这些干燥条件，因为它缺乏从干旱年份中恢复的能力。分析树木对极端气候事件的短期响应似乎是检测树种对干旱耐受性的最有前途和合适的方法。然而，结合本研究中使用的所有方法，可以提供一幅完整的图景，说明缺水如何限制物种。
