Collaborative research: Restricted plasticity of canopy stomatal conductance: A conceptual basis for simpler models of forest transpiration
David Mackay Principal Investigator
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0405306<br/>MacKay<br/>Our proposed project has significant intellectual merit because it explicitly addresses two key<br/>problems facing hydrology. The first problem concerns the opposing views of stomatal control of<br/>water fluxes, with one perspective assuming carbon assimilation control, and the other assuming<br/>an environmental control. Our conceptual model combines both of these perspectives in a unified<br/>mechanistic framework that combines both assimilation and water potential controls on<br/>transpiration. The second problem addressed by our conceptual model is the tendency towards<br/>favoring complex and often mathematically ill-posed canopy models over simpler, verifiable<br/>ones. We explicitly address this fundamental issue in hydrologic modeling by using a novel,<br/>object-oriented canopy model that can flexibly adjust its structure and mechanisms to the data it<br/>is provided. By adjusting model complexity spatially we will gain deep insights on species<br/>plasticity and restrictions thereof across spatial gradients, thus providing a rigorous approach to<br/>testing our conceptual model within our study site in northern Wisconsin.<br/>The knowledge gained from our proposed research has broad implications for land surface<br/>modeling efforts seeking to generate accurate predictions of global change effects on water<br/>cycling. By developing our conceptual model we will be able to provide a relatively simple, but<br/>transportable and scientifically defensible model. Such models are essential foundations for the<br/>creation and implementation of credible state, federal and international policies aimed at<br/>mitigating or otherwise adjusting to the consequences of anticipated global change. The<br/>educational emphasis of this project is multi-faceted. First, we will seek additional funding and<br/>other means of supporting, advising and training an integrated team of undergraduate students<br/>from the economically disadvantaged region of Northern Wisconsin, using this project as the<br/>principal context for their education in Forest Ecology at UW-Madison. Also, in connection with<br/>the NSF Research Collaboration Network project entitled "Chequamegon Ecosystem-<br/>Atmosphere Study," for which Mackay is a core project participant, we will hold a nationally<br/>advertised workshop on multi-scale canopy flux measurements and modeling. The PIs will<br/>continue to recruit and hire minorities and other underrepresented students in our respective<br/>fields.