Individual Tree and Stand Level Influences on the Growth, Vigor, and Decline of Red Oaks in the Ozarks
Individual Tree and Stand Level Influences on the Growth, Vigor, and Decline of Red Oaks in the Ozarks
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个体树和林分水平对奥沙克地区红橡树生长、活力和衰退的影响
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
R. Guyette
中科院分区：
文献类型：
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作者：
S. Voelker;R. Muzika;R. Guyette
反复橡树衰退和死亡事件发生在欧扎克地区几十年来，可能更长。我们采样的年龄序列的1,259个黑色和猩红色橡树（栎velutina林。（Quercus coccus Muench.）为了更好地描述红栎亚属（Redthrobalanus）栎类衰退和死亡的过程。根据近40年来的断面积增长趋势，将树木的生长分为下降、稳定和增长3个活力等级（下降、稳定和健康）。我们将树冠状况指标与绝对BAI和边界线BAI进行了比较，边界线BAI是根据树木尺寸调整的径向生长指标。人们发现，死亡率在最近一次干旱之后就出现了波动，尽管死亡率的下降往往在几十年前就开始了。时间序列的个别树BAI表明，一半的橡树衰退事件煽动一个或两个干旱相关的步骤变化的增长和方差。下降的诱发因素一般表现出显着的，但与树冠条件弱的关系。幸存的橡树生长在高死亡率的立场有较差的树冠条件和生长速度比树木在低死亡率的立场。当最近死树占，同样的高死亡率的立场有显着更大的predecline断面积和放养比低死亡率的立场。因此，竞争力较低的生长环境可能会提供一些缓冲干旱胁迫之前橡树下降，但似乎并没有帮助受灾的立场，提高他们的生长和活力。为.S CI. 54（1）：8-20。
Repeated oak decline and mortality events have occurred in the Ozark region for decades and probably longer. We sampled an age sequence of 1,259 black and scarlet oaks (Quercus velutina Lam. and Quercus coccinea Muench.) to better describe the process of oak decline and mortality in the red oak group (subgenera Erythrobalanus). Trend in basal area increment (BAI) over the most recent 40 years was used to establish three vigor classes for trees with decreasing, stable, or increasing growth (Declining, Stable ,o r Healthy). We compared crown condition measures with absolute BAI and boundary line BAI, a measure of radial growth adjusted for tree size. A pulse of mortality was found to occur just subsequent to the most recent drought, although decline often started decades previously. Time series of individual tree BAI suggests that half of all oak decline events were incited by one or two drought-related step-changes in growth and variance. Predisposing factors to decline generally showed significant but weak relationships with crown conditions. Surviving oaks growing in high-mortality stands had poorer crown conditions and grew more slowly than trees in low-mortality stands. When recently dead trees were accounted for, the same high-mortality stands had significantly greater predecline basal area and stocking than low-mortality stands. Thus, a less competitive growth environment may afford some buffer to drought stress before oak decline but does not appear to help afflicted stands improve their growth and vigor. FOR .S CI. 54(1):8-20.