Estimation of Tropical Forest Leaf Area Index Using Medium-Footprint Lidar

As an important descriptor of forest canopy structure and productivity, leaf surface area strongly relates to respiration, photosynthesis, canopy dynamics, and other biophysical processes. Leaf Area Index (LAI), the amount of one sided leaf area per unit of ground area, has been an important parameter in a variety of ecosystem models. We explore the use of medium-footprint airborne scanning lidar to estimate the spatial distribution of LAI at a landscape scale. Direct estimates of LAI were collected on vertical transects at 71 sites stratified across a tropical wet forest landscape at La Selva Biological Station in Costa Rica. Vertical canopy structure information was collected by the Laser Vegetation Imaging Sensor (LVIS) over La Selva in March of 2005. We analyze the relationship between field-derived LAI estimates and three-dimensional lidar-derived canopy structure information, specifically waveforms and waveform-derived metrics. We also assess the potential of lidar data to scale local estimates of LAI to the landscape level.