How does a combined heatwave+drought influence leaf temperatures?
We used a leaf energy balance model to estimate leaf temperatures of coffee (Coffea arabica) saplings under a combined heatwave and drought event under partial and full sunlight. We found that the drought-induced stomatal closure drastically increases leaf temperatures, suggesting that a combined heatwave and drought would induce significant heat damage to coffee crops. Under full sunlight, leaf temperatures can be ~10degC greater than air temperatures. Marias et al. (2017) Ecology and Evolution |
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What are the physiological and environmental drivers of tree-ring O stable isotopes?
We added a tree-ring O stable isotope submodel to the forest process-based model 3-PG (Predicting Principles in Growth) and applied the new model to the tree-ring C and O stable isotope record of old-growth ponderosa pine near and far from a stream in central Oregon. We found that the O isotope submodel with a Peclet effect improved model estimates of tree-ring O stable isotopes because its calculation utilizes 3-PG growth and allocation processes. Because simulated stand‐level transpiration is used in the O isotope submodel, aspects of leaf‐level anatomy such as the effective path length for transport of water from the xylem to the sites of evaporation in the leaf could be estimated. Ulrich et al. (2019) Ecology |