 This research uses worldview 2, Sentinel-1, and DEM data to estimate vegetation leaf area index, LAI, in a heterogeneous grassland in Canada. For combinations of optical, SAR, and DEM variables were designed and used to evaluate the contribution of each type of data to LAI estimation. Results show that integrating SAR and DEM variables with optical variables improved LAI estimation accuracy, but not substantially, likely due to the heterogeneous nature of the grassland ecosystem. This article was authored by Bing Liu, a new home he.