Dissertation Research: Balancing the influence of biological and architectural diversity on rainforest productivity along an elevation gradient in Hawaii

热带森林覆盖了超过12%的表面积，包含了陆地上50%的固碳，是全球碳循环的重要贡献者。热带森林的碳动态取决于气候条件，如云层覆盖、太阳辐射和温度。在短时间尺度上，即在一年之内，气候通过控制光合作用和呼吸作用的速率直接影响森林生产力。在较长的时间内，气候变化可能会改变森林的三维结构和组成，但这是很难确定的，因为需要大面积的森林来评估这一点，收集现场数据可能是有问题的。因此，研究森林结构、组成和碳动态之间的时空相互作用需要新的方法。这项研究利用了一种新的机载成像系统，激光雷达（光探测和测距），它测量散射光的特性，以及高光谱成像，它使用电磁频谱的大部分提供信息，以开发详细的森林结构3D地图。将同时收集小气候和叶片生理数据，以开发和验证森林光合作用的高分辨率3D模型。通过使用一个研究样带，包括3平方公里的热带森林位于沿着海拔梯度，它将有可能量化的影响，森林结构，组成和气候差异对森林光合作用和生产力的规模以前不可行。该项目将开发一种新的工具，用于大规模和具有成本效益的森林碳动态监测。研究人员还计划制作一个关于这一主题的视频演示，供高中和本科生使用。

Tropical forests cover more than 12% of surface area and contain 50% of sequestered carbon on land, and are important contributors to the global carbon cycle. The carbon dynamics of tropical forests are dependent on climatic conditions, such as cloud coverage, solar radiation, and temperature. At short time scales, i.e. within a year, climate influences forest productivity directly by controlling rates of photosynthesis and respiration. Over longer periods, climate changes may alter forest 3D structure and composition, but this is difficult to determine because large areas of forest are needed to assess this, and collection of field data can be problematical. Thus, studying the spatial and temporal interactions among forest structure, composition and carbon dynamics requires new methods. This study utilizes a new airborne imaging system, LiDAR (Light Detection and Ranging), which measures properties of scattered light, and hyperspectral imaging, which provides information using a vast portion of the electromagnetic spectrum, to develop detailed 3D maps of forest structure. Microclimate and leaf physiology data will be collected simultaneously to develop and validate a high-resolution 3D model of forest photosynthesis. By using a study transect comprising three km2 of tropical forest situated along an elevation gradient, it will be possible to quantify effects of forest structure, composition and climatic differences on forest photosynthesis and productivity at scales not before feasible. This project will develop a new tool for large-scale and cost-effective monitoring of forest carbon dynamics. The researcher also plans to develop a video presentation on this subject for use at the high-school and undergraduate level.