Drought-induced decline and mortality of silver fir differ among three sites in Southern France
Drought-induced decline and mortality of silver fir differ among three sites in Southern France
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DOI：
10.1007/s13595-013-0265-0
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发表时间：
2014-09-01
影响因子：
3
通讯作者：
Davi, Hendrik
中科院分区：
文献类型：
--
作者：
Cailleret, Maxime;Nourtier, Marie;Davi, Hendrik
在地中海地区，近几十年来报告了许多下降和死亡过程，影响了森林动态。这可能是由于夏季干旱严重程度的增加，因此特别影响干旱敏感的树种，如冷杉(Abies Alba Mill.)。为了了解树木生长和树冠状况与死亡概率的关系，采用树轮分析方法比较了健康树、衰落树(树冠受损)和枯死树的径向生长趋势。在法国东南部的三个不同地点，也使用海拔梯度在样地和树木水平上检查了与决定死亡率有关的因素。生长年际变异性较大的个体更容易死亡。在两个地点，枯死的树木在整个生命周期中的生长率较低，而在最后一个地点，它们的幼树生长率较高。在同一地点，树冠受损的树木的生长速度高于健康树木，而且随着时间的推移，它们的径向生长趋势总是与死亡树木的不同。死亡率和树冠损害与海拔高度关系不大，但在不同地点和不同样地之间差异很大，这表明了当地土壤和地形条件的重要性。这些结果表明，死亡概率、树冠状况和生长之间的关系在不同地点可能不同，并突出了土壤条件的影响和在树木死亡研究中评估它们的必要性。
In the Mediterranean area, numerous decline and mortality processes have been reported during recent decades, affecting forest dynamics. They are likely due to increases in summer drought severity and therefore especially affect drought-sensitive species, such as silver fir (Abies alba Mill.).To understand the relationships between tree growth, crown condition and mortality probability, radial growth trends of healthy, declining (showing crown damages) and dead trees were compared using tree-ring analysis. Factors involved in determining this mortality were also examined at the plot and tree level using altitudinal gradients on three contrasted sites in southeastern France.Individuals with higher inter-annual variability in growth were more prone to dieback. At two sites, dead trees displayed lower growth rates over their entire lifetime, while, on the last site, their juvenile growth rate was higher. Trees with crown damage had higher growth rates than healthy trees on one site, and their radial growth trends over time always differed from those of dead trees. Mortality and crown damage were little related to altitude, but strongly differed between sites and among plots underlining the importance of local edaphic and topographic conditions.These results suggest that the relationships among mortality probability, crown condition and growth can differ among sites, and highlight the impact of soil conditions and the need to assess them in tree mortality studies.