Tropical forests contain ~25% of Earth’s terrestrial biomass and exchange more carbon (C) and energy with the atmosphere than any other biome. As such, our poor understanding of how tropical forests will respond to projected increased temperatures severely constrains global predictions. To meet the increasing need for improved understanding of tropical forest responses to global warming, we are implementing field warming experiments in a wet tropical forest in Puerto Rico to evaluate temperature responses of the most influential and biogeochemically active tissues and organisms: leaves, fine roots, and soil microbes. Specifically, we will be warming understory vegetation and soils with an array of Infrared heaters along with complimentary warming of individual canopy leaves and branches. Our concentration on both above and belowground components of the forest will provide an integrated understanding of C storage and flux, which is critical to considerations of how climate effects on tropical forests will feed back to affect future C cycling and climate at the global-scale (Heimann and Reichstein 2008).
Our specific objectives are two-fold:
1) Assess the mechanisms behind and effects of warming on C and nutrient cycling and storage in tropical forest soils.
2) Investigate threshold temperature responses of both canopy and understory tropical tree foliage.
We expect this work will make significant advances in our understanding of coupled biogeochemical processes in a globally important and poorly understood ecosystem that has strong potential feedbacks to climate. This field warming experiment would be the first of its kind in any tropical forest, and the experimental research would be the first to investigate warming response to tropical processes from coordinated above and belowground perspectives in combination with hurricane disturbance. Our focus on the mechanisms regulating temperature responses will allow us to extrapolate results beyond that of a single tropical forest site, leading to wide geographic applicability. This work will additionally provide critical information regarding the vulnerability and adaptation potential of the only tropical forest in the US National Forest System (The Luquillo Experimental Forest inside El Yunque National Forest).
Stay tuned for more updates!