Effects Of Climate Change On Leaf Biomass and Specific Leaf Area Along An Elevation Gradient

Tropical forests are globally important for biodiversity and ecosystem functions that affect global climate via carbon and water balances.  However, we lack experimental understanding of how climate change will affect tropical forests. Previous tropical studies using elevation-climate gradients have shown that leaf biomass is not influenced by elevation across different species present at different elevations, but specific leaf area is, with specific leaf area decreasing as elevation increases. In this study, I examine the effects of different climates at different elevations on biomass allocation to leaves for two common tropical rainforest tree species. I studied two tree species in 17 common garden plots along an elevational gradient (6 high, 6 mid, 5 low; at 1350m, 1050m and 650m respectively), where conspecific individuals were planted downslope to mimic future changes in climate at the native elevation. I quantified leaf biomass by counting the number of leaves in each tree and taking leaf samples to determine individual leaf mass. Our results suggest that biomass allocation to leaves sensitive to climate change is species and population specific.  Also, specific leaf area is affected by climate change differently across species, and for some species is related to both environmental and genotypic factors.  As leaves are directly related to tree development and productivity, and also closely linked with primary production and consequently, carbon sequestration, this study helps shed important insight into how individuals within and across species respond to climate change in that specific leaf area will change, but leaf biomass is not affected.