Tree hydraulics equipment for assessing tree drought mortality under future climate conditions

全球树木死亡率正在上升，在加拿大，由于与气候变暖相关的干旱压力，大片的白杨林正在死亡。随着气温的升高，与干旱相关的森林衰退预计将变得更加普遍，但生长温度和二氧化碳浓度的增加改变了树木的生物量分配和水分运输生理，这可能使树木在未来更容易或更不容易受到干旱的影响。该提案将资助一个高压流量计，用于测量未来气候情景如何改变白杨根、茎和叶的水输送能力。在西部大学的Biotron中，白杨将在三种温度（环境温度，+4和+8摄氏度）和当前环境或两倍环境大气二氧化碳浓度（390 ppm或780 ppm）中的每一种温度下生长，并进行干旱处理。高压流量计将有助于快速测量植物组织对水流的阻力，使我的实验室能够确定干旱如何逐渐影响树木适应不同生长环境的水分输送。这项研究将解决森林管理者在气候变化中预测加拿大森林生长和健康的关键问题，通过深入了解干旱引起的白杨死亡率是否会在未来严重增加。这项研究还将有助于确定在一系列生长条件下，哪些生理性状能提高杨树的耐旱性，使育种者能够开发出更多的抗旱性更好的树木品种，用于生物质和生物燃料的用途，并有助于填补植物水力特性对环境可塑性的基本知识空白。这笔赠款将支持立即培训一名硕士研究生，研究植物水分关系和气候压力对加拿大森林的影响，并促进未来本科生和研究生在紧迫的林业相关问题上的培训。这笔资助将允许我购买对我的早期研究项目发展至关重要的设备，并促进前沿研究，以继续我的实验室在一流期刊上发表高质量的全球变化研究。

Tree mortality rates are increasing globally, and in Canada, large tracts of aspen stands are dying due to drought stress associated with climate warming. While drought-related forest decline is expected to become more common as temperatures rise, increasing growth temperatures and CO2 concentrations alter tree biomass allocation and water transport physiology, which could make trees either more or less vulnerable to drought stress in the future. This proposal will fund a high-pressure flow meter for measuring how future climate scenarios alter aspen water transport capacity in roots, stems and leaves. Aspen will be grown at each of three temperature regimes (ambient temperatures, +4 and +8 degrees Celsius) and either current ambient or twice-ambient atmospheric CO2 concentrations (390 ppm or 780 ppm) in the Biotron at Western University, and subjected to a drought treatment. The high-pressure flow meter will facilitate rapid measurements of resistance to water flow in plant tissues, allowing my lab to determine how drought progressively affects water transport in trees acclimated to different growth environments. The research will address crucial problems for forest managers in projecting Canada's forest growth and health in a changing climate by providing insight into whether drought-induced aspen mortality will increase in severity in the future. This study will also help identify which physiological traits improve aspen drought tolerance under a suite of growth conditions, allowing breeders to develop more stress resistant tree varieties for biomass and biofuel purposes, and helping fill a basic knowledge gap on the plasticity of plant hydraulic characteristics to the environment. The grant will support the immediate training of a Masters student in plant water relations and climate stress effects on Canada's forests, as well as facilitating future undergraduate and graduate student training in pressing forestry-related issues. This grant will allow me to buy equipment crucial to the development of my research program as an early career researcher and facilitate cutting-edge research to continue my lab's record of publishing high-quality global change research in premier journals.