A Retrospective Dendroecology of American Chestnut in the Southern Appalachian Forest

[509307] Stahle灾难性的栗树疫病摧毁了东部落叶林中最重要的物种之一，并引发了可能持续几个世纪的动态森林反应。由于缺乏枯萎前森林的定量数据，使得了解枯萎对环境影响的工作变得复杂。幸运的是，在一些选定的森林中，人们仍然可以从枯死的原木中获得准确而详细的栗子生长记录，否则这些森林基本上没有受到干扰。该项目将在阿巴拉契亚南部地区的六个古老森林地点，从枯萎病死亡的原木中开发200至300年的美洲栗树年轮年表。还将在同一地点为铁杉和橡树的三个年龄类别开发树木年轮年表。这三个类别将是古树，枯萎前的小树和枯萎后的小树。将开发至少24个年表，包括3个栗子和9个橡树从干旱地点。在可能的情况下，将使用从早期历史建筑中回收的古老板栗木材来延长板栗年表。所有年表将与早在1871年开始的每月气候数据进行比较，以确定板栗在枯萎前森林中的气候响应，以及它在枯萎前和枯萎后森林中的两个重要的前伙伴。这些年表将被用来检验关于在枯萎病之后南部阿巴拉契亚森林生态系统的气候强迫可能发生变化的假设。pi将检验栗子成熟生长速率受栗子特有的特定气候变量限制的假设。如果这是真的，这种独特的气候影响对一个重要部分的预定居森林已经大大减少了选择性去除栗子。他们还将验证一个假设，即由疫病引发的小气候变化改变了特定的季节性气候变量，这些气候变量最限制了栗子的生长，如铁杉和橡树。提出的年轮年表将挽救一份宝贵的栗子生长记录，该记录已被忽视了50多年，可能很快就会腐烂，无法恢复。

9509307 Stahle The catastrophic chestnut blight destroyed one of the most important species of the eastern deciduous forest and initiated dynamic forest responses that may last for centuries. The scarcity of quantitative data on pre-blight forests has complicated efforts to understand the environmental impact of the blight. Fortunately, an exact and detailed record of chestnut growth can still be recovered from blight-killed logs in a few selected forests that are otherwise largely undisturbed. This project will develop 200- to 300-year long tree-ring chronologies of American Chestnut from blight killed logs at six ancient forest locations in the southern Appalachian region. Tree-ring chronologies will also be developed at the same locations for three age categories of hemlock, and oak. These three categories will be ancient, young pre-blight, and young post-blight trees. At least 24 chronologies will be developed, including 3 chestnut and nine oak from xeric sites. The chestnut chronologies will be extended when possible with ancient chestnut timbers recovered from early historic buildings. All chronologies will be compared with monthly climate data which begin as early as 1871 in order to define the climate response of chestnut in pre-blight forests, and two of its important former associates in pre- and post-blight forests. The chronologies will be used to test hypotheses concerning possible changes in the climate forcing of southern Appalachian forest ecosystems following the blight. The PIs will test the hypothesis that the mature growth rates of chestnut were limited by specific climate variables unique to chestnut. If true, this unique climate influence on an important fraction of presettlement forests has been greatly diminished by the selective removal of chestnut. They will also test the hypothesis that the microclimate changes initiated by the blight have altered the specific seasonal climate variables most limiting to the growth of chestnut associates such as hemlock and oak. The p roposed tree-ring chronologies will salvage a priceless record of chestnut growth that has been ignored for over 50 years and may soon decay beyond recovery.