Mature oak (Quercus spp.) and hickory (Carya spp.) trees are gradually being replaced by more shade-tolerant tree species across the eastern U.S., likely due to fire suppression and increased precipitation. Oaks and hickories are highly valuable to wildlife; therefore, studying their mortality patterns can provide information on the longevity of habitat quality for many animal species. Oak mortality has most often been studied following large oak decline events, but background mortality rates in forests with aging oak and hickory canopies warrant equal attention, especially in the context of widespread oak and hickory regeneration failure. We studied background mortality rates of five oak and one hickory species over a 23–25 year time period (1993–1995 to 2018), using 82 1/20th hectare permanent plots on the Marietta Unit of the Wayne National Forest in southeastern Ohio. We calculated mortality rates based on remeasurement of individual trees for white oak (Quercus alba), chestnut oak (Quercus montana), northern red oak (Quercus rubra), black oak (Quercus velutina), scarlet oak (Quercus coccinea), and pignut hickory (Carya glabra). For each of these species other than scarlet oak, we also modeled the relationships of mortality probability with a priori topographic, soil, stand structural, and individual tree covariates, using a mixed-effects logistic regression framework. The species with the highest mortality rate was scarlet oak (61.3%), followed by northern red oak (41.4%), black oak (26.7%), pignut hickory (23.9%), white oak (23.4%), and chestnut oak (19.1%). In our models, northern red oak mortality was associated with more mesic slope positions, shallower solums, more acidic soils, and older stand ages. Pignut hickory and chestnut oak mortality rates were associated with higher basal areas on the plot, while white oak mortality showed the opposite pattern. Our data suggest that red oak subgenus trees in mature forests of our area will become increasingly uncommon relative to white oak subgenus trees, as the result of higher mortality rates likely related to the shorter lifespans of these species. Particularly vulnerable areas may include more mesic topographic positions, shallower or more acidic soil, and older stands. Since maintaining oak subgenus diversity is beneficial to wildlife diversity in the eastern U.S., managers in areas with extensive mature mixed-oak forests could choose to favor the red oak subgenus when conducting silvicultural treatments.

中文翻译：

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橡木的死亡率（诱发因素的影响栎）和山核桃（山核桃成熟森林在俄亥俄州阿巴拉契亚经历mesophication）物种

在美国东部，成熟的橡树（Quercus spp。）和山核桃（Carya spp。）树逐渐被更多的耐荫树种所取代，这可能是由于灭火和降水增加所致。橡树和山胡桃对野生动植物具有很高的价值。因此，研究它们的死亡率模式可以提供许多动物物种栖息地质量寿命的信息。人们通常在发生大量的橡树衰落事件之后研究橡树死亡率，但是在具有老化的橡树和山胡桃冠层的森林中，本底死亡率值得同等关注，尤其是在广泛的橡树和山核桃树再生失败的背景下。我们研究了23-25年（1993-1995年至2018年）期间5种橡树和1种山核桃种的背景死亡率，在俄亥俄州东南部韦恩国家森林的玛丽埃塔单元上使用82 1/20公顷永久性地块。我们基于对白橡树（Quercus alba），栗树橡树（Quercus montana），北部红橡树（Quercus rubra），黑橡树（Quercus velutina），猩红色橡树（Quercus coccinea）和栗木山核桃的单棵树的重新测量来计算死亡率（山核桃）。对于除猩红色橡树以外的所有其他物种，我们还使用混合效应逻辑回归框架对先验地形，土壤，林分结构和单个树木协变量的死亡率概率关系进行了建模。死亡率最高的物种是猩红色橡树（61.3％），其次是北部红橡树（41.4％），黑橡树（26.7％），栗木山核桃（23.9％），白橡树（23.4％）和板栗橡树（ 19.1％）。在我们的模型中 北部红橡树的死亡率与更多的中坡位置，更浅的贫民窟，更酸性的土壤和更老的林分年龄有关。栗树山核桃和板栗橡树的死亡率与该地块较高的基础面积相关，而白橡树的死亡率则呈现相反的规律。我们的数据表明，相对于白橡树亚种，相对于白橡树亚种，我们地区成熟森林中的红橡树亚种将变得越来越少见，这是由于这些物种的寿命较短而导致的死亡率较高。特别脆弱的地区可能包括更多的中性地形位置，更浅或更酸性的土壤以及较旧的林分。由于维持橡木亚属的多样性有利于美国东部的野生动植物多样性，