Heavy and frequent thinning promotes drought adaptation in Pinus sylvestris forests.
Heavy and frequent thinning promotes drought adaptation in Pinus sylvestris forests.
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DOI：
10.1002/eap.1373
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发表时间：
2016-10
期刊：
影响因子：
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通讯作者：
J. Sohn;F. Hartig;M. Kohler;J. Huss;J. Bauhus
中科院分区：
文献类型：
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作者：
J. Sohn;F. Hartig;M. Kohler;J. Huss;J. Bauhus
在气候变化的情况下，许多区域的干旱及其对森林生态系统的负面影响预计会增加。有人建议，密集间伐可以在短期内减少干旱对已建森林的影响。然而，以往关于疏伐对干旱影响的研究大多局限于单一的森林地点。因此，目前还不清楚间伐的好处有多普遍和持久。这项研究评估了间伐的潜力，以提高耐旱性的广泛传播的苏格兰松（欧洲赤松）在中欧。我们假设：（1）增加间伐强度有利于维持作物在干旱期间的径向生长（抗性）和干旱后的恢复，（2）这些对生长的益处随着自上次间伐以来的时间和林龄的推移而减少，（3）它们可能取决于干旱的严重程度以及干旱前后的水分限制。为了验证这些假设，我们评估了在德国的4个长期间伐实验中，间伐制度，林分年龄和干旱严重程度对129棵苏格兰松树的径向生长的影响。我们发现，间伐改善了干旱后径向生长的恢复，并在较小程度上提高了干旱期间的生长阻力。干旱后的生长恢复是最高的第一次间伐干预后，在最近和严重间伐的立场。然而，与未间伐的林分相比，随着上次间伐以来的时间推移，这种影响逐渐减弱，甚至可能变成负值。此外，疏伐有助于避免干旱后与年龄相关的生长阻力（和恢复）下降。干旱后的恢复，而不是在干旱期间的电阻，是在干旱期间的水分限制。这是第一个研究，分析干旱相关的径向生长在一个物种的树木在几个不同年龄的立场。间伐强度和自上次间伐以来的时间之间的相互作用强调了区分间伐的短期和长期影响的重要性。根据我们的分析，只有间伐制度，相对重和频繁的间伐干预将增加松树林的耐旱性。
Droughts and their negative effects on forest ecosystems are projected to increase under climate change for many regions. It has been suggested that intensive thinning could reduce drought impacts on established forests in the short-term. Most previous studies on the effect of thinning on drought impacts, however, have been confined to single forest sites. It is therefore still unclear how general and persisting the benefits of thinning are. This study assesses the potential of thinning to increase drought tolerance of the wide spread Scots pine (Pinus sylvestris) in Central Europe. We hypothesized (1) that increasing thinning intensity benefits the maintenance of radial growth of crop trees during drought (resistance) and its recovery following drought, (2) that those benefits to growth decrease with time elapsed since the last thinning and with stand age, and (3) that they may depend on drought severity as well as water limitations in pre- and post-drought periods. To test these hypotheses, we assessed the effects of thinning regime, stand age, and drought severity on radial growth of 129 Scots pine trees during and after drought events in four long-term thinning experiments in Germany. We found that thinning improved the recovery of radial growth following drought and to a lesser extent the growth resistance during a drought event. Growth recovery following drought was highest after the first thinning intervention and in recently and heavily thinned stands. With time since the last thinning, however, this effect decreased and could even become negative when compared to unthinned stands. Further, thinning helped to avoid an age-related decline in growth resistance (and recovery) following drought. The recovery following drought, but not the resistance during drought, was related to water limitations in the drought period. This is the first study that analyzed drought-related radial growth in trees of one species across several stands of different age. The interaction between thinning intensity and time since the last thinning underline the importance to distinguish between short- and long-term effects of thinning. According to our analysis, only thinning regimes, with relatively heavy and frequent thinning interventions would increase drought tolerance in pine stands.