DISSERTATION RESEARCH: Environmental Determinants of Subalpine Forest-grassland Ecotones in the Southern Rocky Mountains

本研究的目的是区分气候因素和土壤性质的相对作用，在确定结果的树木和草地物种之间的竞争，在美国西南部山区的亚高山草甸的边界。 研究人员将沿着自然环境梯度进行观察研究，并将进行实地实验，以区分冷空气排水与土壤肥力对树苗存活和与草竞争的影响。 他们还将开发景观动态的历史重建，以补充梯度和实验研究。 该项目的结果可能有助于解释与土地利用做法和气候有关的树线（草地-林地边界）迁移的历史趋势。

This study is designed to distinguish the relative roles of climatic factors and soil properties in determining the outcome of competition among tree and grassland species at the borders of subalpine meadows in mountain regions of the southwestern US. The investigators will conduct observational studies along natural environmental gradients and will perform field experiments to distinguish the effects of cold air drainage vs. soil fertility on tree seedling survival and competition with grasses. They will also develop historical reconstructions of landscape dynamics to complement the gradient and experimental studies. The project results could help to explain historical trends in tree-line (grassland-woodland boundaries) migration in relation to land use practices and climate.