This project seeks to improve land surface models (LSMs) using new and existing data collections by building upon a data assimilation system under development for the Community Land Model (CLM). We propose to augment the available carbon and water flux observations with data products derived from a network of already installed phenology monitoring webcams, seasonal measurements of tree growth and tree-ring based estimates of primary productivity. The project is coordinated in phases; (1) data collection, (2) analysis and (3) synthesis.