Collaborative Research: Restricted Plasticity of Canopy Stomatal Conductance: A Conceptual Basis for Simpler Spatial Models of Forest Transpiration

0405318 Kruger从与美国全球变化研究计划有关的水和碳小组最近的报告中可以清楚地看出，森林系统冠层气孔导度的准确预测对于理解地表-大气通量以及它们如何受到气候和土地利用变化的影响至关重要。事实上，土地利用的变化正在产生更破碎的景观，而这些景观在目前的地表模型中并不容易表示。目前的森林通量模型是在研究范式下开发的，在研究范式中，确定了均匀的林分，在这些林分的中心进行通量测量，然后将在这里学到的知识外推到整个林分及更远的地方。鉴于植物群落的空间复杂性，这种方法既没有必要，也没有道理。该项目旨在开发一个森林蒸腾的概念模型，该模型包含气孔控制的固有空间变异性，同时保留易于处理的概括性指标，这是气孔导度经验模型的标志。我们的概念模型是基于这样的想法，即冠层气孔导度主要是由水势调节时，水通量高，重要的水文进口。我们认为，物种的可塑性冠层气孔导度，这决定了其空间变异性和量化的挑战，遵循一个线性关系，该关系与一个容易量化的参考电导率无关。从与美国全球变化研究计划有关的水和碳小组最近的报告中可以清楚地看出，森林系统中冠层气孔导度的准确预测是这对于了解地表-大气通量及其如何受到气候和土地利用变化的影响至关重要。事实上，土地利用的变化正在产生更破碎的景观，而这些景观在目前的地表模型中并不容易表示。目前的森林通量模型是在研究范式下开发的，在研究范式中，确定了均匀的林分，在这些林分的中心进行通量测量，然后将在这里学到的知识外推到整个林分及更远的地方。鉴于植物群落的空间复杂性，这种方法既没有必要，也没有道理。该项目旨在开发一个森林蒸腾的概念模型，该模型包含气孔控制的固有空间变异性，同时保留易于处理的概括性指标，这是气孔导度经验模型的标志。我们的概念模型是基于这样的想法，即冠层气孔导度主要是由水势调节时，水通量高，重要的水文进口。我们建议，物种可塑性冠层气孔导度，这决定了其空间变异性和量化的挑战，遵循线性关系，是一个容易量化的参考电导关闭。

0405318KrugerIt is clear from recent reports by the water and carbon groups associated with the United States Global Change Research Program that accurate predictions of canopy stomatal conductance in forested systems are critical for the understanding of land surface - atmosphere fluxes and how they are affected by climate and land use changes. Indeed, land use changes are producing more fragmented landscapes and these are not readily represented in current land surface models. Current forest flux models were developed under the paradigm of research in which uniform forest stands are identified, flux measurements are made in the centers of these stands, and then what is learned here is extrapolated to the entire stand and beyond. This approach is neither necessary nor justified given the spatial complexity of vegetative communities. This projectseeks to develop a conceptual model of forest transpiration that embraces the inherent spatial variability of stomatal control while retaining a tractable measure of generalizability that is the hallmark of empirical models of stomatal conductance. Our conceptual model is based on the idea that canopy stomatal conductance is regulated primarily by water potential when water fluxes are high and of significant hydrologic import. We propose that species plasticity in canopy stomatal conductance, which determines its spatial variability and challenge for quantifying, follows a linear relationship that is keyed off of an easily quantifiable reference conductance0405318KrugerIt is clear from recent reports by the water and carbon groups associated with the United States Global Change Research Program that accurate predictions of canopy stomatal conductance in forested systems are critical for the understanding of land surface - atmosphere fluxes and how they are affected by climate and land use changes. Indeed, land use changes are producing more fragmented landscapes and these are not readily represented in current land surface models. Current forest flux models were developed under the paradigm of research in which uniform forest stands are identified, flux measurements are made in the centers of these stands, and then what is learned here is extrapolated to the entire stand and beyond. This approach is neither necessary nor justified given the spatial complexity of vegetative communities. This projectseeks to develop a conceptual model of forest transpiration that embraces the inherent spatial variability of stomatal control while retaining a tractable measure of generalizability that is the hallmark of empirical models of stomatal conductance. Our conceptual model is based on the idea that canopy stomatal conductance is regulated primarily by water potential when water fluxes are high and of significant hydrologic import. We propose that species plasticity in canopy stomatal conductance, which determines its spatial variability and challenge for quantifying, follows a linear relationship that is keyed off of an easily quantifiable reference conductance.