Ways forward: A globally-distributed treeline collaboration

The Global Treeline Range Expansion Experiment (G-TREE) is a globally distributed, collaborative project aimed at testing the generality of mechanisms driving treeline position. Global research networks, in which standardized local data collection efforts are aggregated across many sites, have made unparalleled contributions to understanding complex ecological problems. Participating researchers from North America, South America, and Europe began implementing the field experiment in 2013 at arctic and alpine treeline sites. Our structured experimental design permits the disentanglement of multiple factors that may constrain treeline expansion, providing empirical data on where, and under what circumstances, treeline expansion can occur globally.