What experiments can (and can’t) tell us about climate change impacts at treeline

Forests, tundra, and the treeline ecotone provide critical ecosystem services, making robust climate change predictions for these systems a globally important challenge. Experimental manipulation has played an important role in ecological research, helping to infer cause and effect in complex coupled systems. However, manipulating climate to assess potential climate change impacts is fraught with challenges. Observation of climate and ecological variability in space and time provides an alternate, albeit more correlative, approach. We will highlight factors experimentalists must consider when manipulating climate in treeline ecosystems and propose an approach to integrating experiments with observations of natural variation.