Partitioning MODIS Leaf Area Index for Sub-Saharan Africa

Research Project Short Description: 
The project involves partitioning MODIS aggregate leaf area index (LAI) into herbaceous and woody cover components in Sub-Saharan Africa
Principal Investigator(s): 
Niall Hanan
Njoki Kahiu

Project Summary Mixed tree-grass and shrub-grass vegetation associations are one of the most spatially extensive and widely distributed forms of terrestrial vegetation on earth. They constitute significant fractions of all continents, except Antarctica, in tropical, subtropical and temperate bioclimatic regions. While global tree-grass systems are diverse in their phylogeny, physiology and plant morphology, they share the key structural characteristic of woody plants distributed in the landscape at densities low enough to allow significant growth of herbaceous plants (mostly grasses) underneath and between them. Despite the importance of tree-grass systems in earth system processes and human well-being, they are not well represented in remote sensing and modeling capabilities. Ecosystems characterized by horizontally and vertically complex tree-grass mixtures are inherently difficult to measure with remote sensing and difficult to represent in ecosystem and earth system models. Here we leverage emerging data on slowly varying canopy structure (tree cover) to provide a key constraint in the estimation of rapidly (i.e. seasonally) varying tree and grass leaf area index (LAI). This tree-grass separation in remote sensing data has not, to our knowledge, been attempted before at regional and continental scales using MODIS data.