Doctoral Dissertation Research: Range of Variability in Fire Regimes of Table Mountain Pine (Pinus pungens Lamb.) Stands, Jefferson National Forest, Virginia

准确测定阿巴拉契亚山脉中部黄松林分的历史和当前火灾状况（包括火灾频率、季节性和空间尺度），对于在历史上以松树为主的地区恢复逐渐减少的松树种群至关重要。 桌山松（Pinus pungens Lamb.），主要关注的黄松，其分布范围从北方格鲁吉亚延伸到宾夕法尼亚中部，并且是美国中东部高地的橡树松树混交林的主要组成部分。 然而，经过60年的灭火，不耐火的硬木和灌木在黄松林中占据主导地位，阻碍了桌山松的再生。 这个博士论文研究改进项目的目标是（1）确定阿巴拉契亚山脉中部黄松林的历史和当前火灾状况，（2）确定队列建立如何与过去的火灾联系起来，（3）通过分析森林组成数据的变化来确定未来的林分组成，以及（4）使用GIS来确定特定地点火灾状况之间存在的关系（例如，在单独的松树林之间的火的运动）。 在弗吉尼亚州西南部杰斐逊国家森林的四座山上，人们收集了火灾留下的树木、树桩、原木和障碍物，并通过树木年代学分析确定了它们的伤痕。 这些树木年轮分析提供的信息表明，火灾发生和队列建立在一个立场，建立了许多树木，符合一个已知的火灾年之间的密切联系。 火灾历史提供了火灾频率和季节性的信息，但没有火灾如何影响植被。 将进行植被结构分析，以澄清火灾对一个地区物种组成的影响。 火灾历史信息，结合年龄结构分析，预计将提供一个详细的总结，目前的组成黄松人口，他们的关系，过去的火灾，和他们的预测生存在目前的火灾制度。桌山松的重要性在于它的生态价值，增加景观多样性，保护地区容易受到侵蚀，为许多野生动物提供食物和掩护。 桌山松在重大火灾发生后的山林再生中发挥着重要作用。 火生态学家和森林研究人员预测，不耐火的物种最终将主宰传统的松树网站，除非火恢复到这些生态系统。 在没有黄松的情况下，不耐火的硬木在阿巴拉契亚山脉中部的森林中占据主导地位。 物种组成的这种变化，特别是在荒地-城市界面，将使意外的、大规模的、灾难性的火灾更有可能发生，而火灾后健康的森林再生的机会很小。 这项研究将提供必要的数据，森林管理人员重新引入火的黄松站，以保持他们在一个健康的状态。 作为博士论文研究改进奖，该奖项还将提供支持，使有前途的学生建立一个强大的独立的研究生涯。

An accurate determination of the historic and current fire regimes (including fire frequency, seasonality, and spatial scale) of yellow pine stands in the central Appalachian Mountains is crucial in efforts to restore diminishing pine populations in historically pine-dominated areas. Table Mountain pine (Pinus pungens Lamb.), the yellow pine of principle interest, has a distribution that extends from northern Georgia into central Pennsylvania and is a major component of the mixed oak-pine forest of central eastern U.S. highlands. After 60 years of fire suppression, however, fire-intolerant hardwoods and shrubs are achieving dominance in yellow pine stands and hindering the regeneration of Table Mountain pine. The goals of this Doctoral Dissertation Research Improvement project are (1) to determine the historic and current fire regimes of yellow pine stands in the central Appalachian Mountains, (2) to determine how cohort establishments are linked to past fires, (3) to determine the future stand composition by analyzing the changes in forest composition data, and (4) to use GIS to determine the relationships that exist among site-specific fire regimes (e.g., the movement of fire between individual pine stands). Collection of fire-scarred trees, stumps, logs, and snags has taken place on four mountains across the Jefferson National Forest of southwestern Virginia, and their scars have been dated through dendrochronological analyses. Information provided by these tree-ring analyses has shown a close association between fire occurrence and cohort establishment within a stand, with the establishment of many trees that coincide with a known fire year. Fire histories have provided information on the frequency and seasonality of fires, but not how fires affect vegetation. Age-structure analysis will be conducted to clarify the effects of fire on the species composition of an area. Fire history information, combined with age structure analysis, are expected to provide a detailed summary of the current composition of yellow pine populations, their relationships with past fire, and their prognosis for survival under the current fire regime.The importance of Table Mountain pine lies in its ecological value by increasing landscape diversity, by protecting areas prone to erosion, and by providing food and cover to a number of wildlife species. Table Mountain pine plays a major role in the regeneration of mountain forests after major fire occurrences. Fire ecologists and forest researchers predict that fire-intolerant species will eventually dominate traditional pine sites unless fire is restored to these ecosystems. In the absence of yellow pine, fire-intolerant hardwoods achieve dominance in central Appalachian forests. Such a change in species composition, particularly in the wildland-urban interface, would make accidental, large-scale, catastrophic fires more likely with little chance for healthy forest regeneration after the fire. This research will offer the data necessary for forest managers to reintroduce fire to yellow pine stands for the purpose of maintaining them in a healthy state. As a Doctoral Dissertation Research Improvement award, this award also will provide support to enable a promising student to establish a strong independent research career.