Tree Trait Task Force (3TF) - Tree Functional Trait Database

Tree Trait Task Force (3TF) - Tree Functional Trait Database<br>Corresponding author :[e-mail]@[e-mail]<br>Our dataset was originally created to offer scientists and the public a “ready-to-use” functional trait database for trees. This dataset is the first step within a larger project to create a standardized tree functional trait database for applied projects.We aim to offer a clean and uniform database of traits with clear selection criteria for its retained values.This database was compiled from TRY database (Kattge et al., 2011), the Kew Seed Information Database, and from the literature. The species list of trees used for the database was originally obtained form the Global Tree Search database (https://tools.bgci.org/global_tree_search.php) and was defined as :”a woody plant with usually a single stem growing to a height of at least two metres, or if multi-stemmed, then at least one vertical stem five centimetres in diameter at breast height.”. To this species list was added subspecies and varieties phylogenetically related. We ended up with a list of 5244 tree species. Using this species list, we requested trait data from TRY database for 8 functional traits (specific leaf area, seed mass, wood density, leaf nitrogen content, lead dry matter content, leaf life span, net maximum photosynthesis, specific root length). The same 8 traits were requested from the BIEN database for the same list of species. We then triage the traits data to ensure that only values which matched our criteria were retained. Our criteria were that the trait value was measured on mature trees (no seedling, no young shoot) in the field on trees growing in their natural environment (without experimental manipulation – or from control group) ; that measurement units are correct and measured according to internationally validated protocols (Cornelissen – perez-arguindeguy) ; that measurement can be traced back to a single original publication ; all remaining possible outliers were verified manually by going back to the original publication for confirmation. This data selection process ensured that the traits values are trustworthy and unique, meaning that the same original measurement was not present several times in the database.<br>Full dataset description will follow soon