What mediates tree mortality during drought in the southern Sierra Nevada?
What mediates tree mortality during drought in the southern Sierra Nevada?
复制标题
内华达山脉南部干旱期间树木死亡的原因是什么？
DOI：
10.1002/eap.1620
复制
发表时间：
2017
期刊：
影响因子：
--
通讯作者：
G. Asner
中科院分区：
文献类型：
--
作者：
T. Paz;P. Brodrick;N. Vaughn;Adrian J. Das;N. Stephenson;K. Nydick;G. Asner
严重干旱有可能造成森林内的选择性死亡，从而引起森林物种组成的变化。由于干旱和虫害的爆发，内华达山脉南部的山麓和加利福尼亚的山脉经历了大面积的森林枯死。利用美国卡内基航空天文台（CAO）的高保真成像光谱（HiFIS）和光探测与测距（LiDAR）技术，研究了红杉国家公园森林枯死对干旱胁迫下物种组成的影响。我们的目标是(1)量化内华达山脉南部沿海拔梯度调节树木死亡的特定地点条件，(2)评估死亡事件发生的可能性更大的地方，(3)估计沿海拔梯度哪些树种有更大的死亡可能性。建立了一系列统计模型，对树种组成进行分类，确定树木死亡率，并对不同环境因素的影响进行空间量化分析，以评估死亡事件发生的可能性。在海拔梯度较低的部分，在西南和西向的斜坡上，在土壤较浅的地区，在较浅的斜坡上，以及在离水较远的地方，观察到较高的死亡率。所有这些因素都与整个景观的场地水平衡有关。在海拔梯度上，黄松（Pinus ponderosa）和蓝柏松（Pinus lambertiana）的死亡率具有物种特异性，低海拔地区主要受影响。森林内的选择性死亡可能沿着海拔梯度驱动群落组成的长期变化。
Severe drought has the potential to cause selective mortality within a forest, thereby inducing shifts in forest species composition. The southern Sierra Nevada foothills and mountains of California have experienced extensive forest dieback due to drought stress and insect outbreak. We used high-fidelity imaging spectroscopy (HiFIS) and light detection and ranging (LiDAR) from the Carnegie Airborne Observatory (CAO) to estimate the effect of forest dieback on species composition in response to drought stress in Sequoia National Park. Our aims were (1) to quantify site-specific conditions that mediate tree mortality along an elevation gradient in the southern Sierra Nevada Mountains, (2) to assess where mortality events have a greater probability of occurring, and (3) to estimate which tree species have a greater likelihood of mortality along the elevation gradient. A series of statistical models were generated to classify species composition and identify tree mortality, and the influences of different environmental factors were spatially quantified and analyzed to assess where mortality events have a greater likelihood of occurring. A higher probability of mortality was observed in the lower portion of the elevation gradient, on southwest- and west-facing slopes, in areas with shallow soils, on shallower slopes, and at greater distances from water. All of these factors are related to site water balance throughout the landscape. Our results also suggest that mortality is species-specific along the elevation gradient, mainly affecting Pinus ponderosa and Pinus lambertiana at lower elevations. Selective mortality within the forest may drive long-term shifts in community composition along the elevation gradient.
DOI：
10.1073/pnas.0505734102
发表时间：
2005-10-18
影响因子：
11.1
作者：
Breshears, DD;Cobb, NS;Meyer, CW
通讯作者：
Meyer, CW