Can Future CO₂ Concentrations Mitigate the Negative Effects of High Temperature and Longer Droughts on Forest Growth?

Abstract

(1) Background: Climate change may subject forests to climate conditions to which they are not adapted. Elevated temperatures can potentially reduce net photosynthesis by increasing respiration rates and increasingly long droughts dramatically increase morbidity. While CO₂ enrichment enhances productivity, it is not clear to what extent CO₂ enrichment can offset the negative effects of elevated temperatures and longer droughts; (2) Methods: We used a mechanistic landscape model to conduct controlled simulation experiments manipulating CO₂ concentration, temperature, drought length and soil water capacity; (3) Results: We found that elevated CO₂ stimulates productivity such that it dwarfs the negative effect caused by elevated temperature. Energy reserves were not as strongly mitigated by elevated CO₂, and the mortality of less competitive cohorts increased. Drought length had a surprisingly small effect on productivity measures, but longer droughts increased the risk of mortality; (4) Conclusions: Elevated CO₂ compensated for the negative effect of longer droughts in terms of productivity measures, but not survival measures.

Citation

Gustafson, Eric; Miranda, Brian; Sturtevant, Brian. 2018. Can Future CO₂ Concentrations Mitigate the Negative Effects of High Temperature and Longer Droughts on Forest Growth?. Forests. 9(11): 664-. 18 p. https://doi.org/10.3390/f9110664.