Growth patterns prior to mortality of mature Abies lasiocarpa in old-growth subalpine forests of southern British Columbia
Growth patterns prior to mortality of mature Abies lasiocarpa in old-growth subalpine forests of southern British Columbia
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DOI：
10.1016/j.foreco.2007.11.022
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发表时间：
2008-04
影响因子：
3.7
通讯作者：
J. Antos;R. Parish;G. Nigh
中科院分区：
文献类型：
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作者：
J. Antos;R. Parish;G. Nigh
冠层树木的死亡是森林动态中的一个重要过程，可能是突然的，与过去的事件无关，也可能是长期衰退的顶点。对于3个恩格尔曼云杉（Picea engelmannii Parry）-亚高山冷杉（Abies lasiocarpa [Hook.] Nutt.）森林，我们重建了冠层大小A的增长。lasiocarpa用树木年代学方法捕捉。我们将死亡前的生长幅度和速率与对照组（即，生活）一组树。在死亡前的最后10年，断面积增量平均大大低于对照树。死亡的树木开始分化生长，平均在死亡前20-40年。大约50%的死亡树木长期生长缓慢，30%的树木生长明显下降，而20%的树木在死亡前生长良好。增长的变化率表明相对于对照组的树木下降，但两组之间的重叠是广泛的。虽然有些树木突然死亡，没有证据表明，在他们的年轮模式即将死亡，总的来说，我们的研究结果表明，冠层A。在这些古老的森林中，毛果芸香的生长是一个渐进的过程，与长期的低生长或长期的生长下降有关。
Mortality of canopy trees is an important process in forest dynamics, and can be sudden without relationship to past events or the culmination of a long decline. For three Engelmann spruce (Picea engelmannii Parry)-subalpine fir (Abies lasiocarpa [Hook.] Nutt.) forests, we reconstructed growth of canopy-size A. lasiocarpa snags using dendrochronological procedures. We compared both the magnitude and rate of growth prior to death to a control (i.e., living) group of trees. Basal area increment averaged substantially less during the last 10 years before death than for control trees. Trees that died started diverging in growth, on average, 20–40 years before death. About 50% of trees that died had chronically slow growth, 30% had pronounced declines in growth, whereas 20% had good growth up to death. The rate of change in growth indicated a decline relative to the control group of trees but overlap was extensive between the two groups. Although some trees die abruptly without evidence in their ring patterns of impending mortality, overall our results indicate that mortality of canopy A. lasiocarpa in these old forests is a gradual process related to long periods of low growth or long-term declines in growth.