Responses of Cacao Tree Carbon Cycling to Light Exposure and Temperature Change.

Climate change has been altering environmental conditions globally by increasing temperatures. Understanding how tropical understory species like Theobroma cacao (chocolate) will respond to these changes is crucial. In the summer of 2024, a comprehensive study was conducted to analyze the growth and photosynthetic rates of cocoa trees under varying light and temperatures. Due to the lack of a natural high-temperature analogue, the study utilized the rainforest mountain in Biosphere 2. Using a LI-6800 paired with a fluorometer, leaf gas exchanges and chlorophyll fluorescence were measured on the cocoa leaves. Eight trees were selected across three elevation levels, and vegetative assessments—including stem diameter, leaf area per stem size, and wood density—were recorded at each branch site. The study showed significant variation in growth and photosynthetic performance across different light and temperature treatments. Cocoa trees exposed to partial light exhibited the highest growth rates and photosynthetic efficiency, while those in full sunlight and deep shade showed signs of stress and reduced growth. In conclusion, this study lays the groundwork for future research on the effects of temperature and light variations on cocoa trees.