Sharp decline in future productivity of tropical reforestation above 29 degrees C mean annual temperature

Tropical reforestation is among the most powerful tools for carbon sequestration. Yet, climate change impacts on productivity are often not accounted for when estimating its mitigation potential. Using the process-based forest growth model 3-PGmix, we analyzed future productivity of tropical reforestation in Central America. Around 29 degrees C mean annual temperature, productivity sharply and consistently declined (-11% per 1 degrees C of warming) across all tropical lowland climate zones and five tree species spanning a wide range of ecological characteristics. Under a high-emission scenario (SSP3-7.0), productivity of dry tropical reforestation nearly halved and tropical moist and rain forest sites showed moderate losses around 10% by the end of the century. Under SSP2-4.5, tropical moist and rain forest sites were resilient and tropical dry forest sites showed moderate losses (-17%). Increased vapor pressure deficit, caused by increasing temperatures, was the main driver of growth decline. Thus, to continue following high-emission pathways could reduce the effectiveness of reforestation as climate action tool.

Automated summary

Tropical reforestation is a powerful tool for carbon sequestration, but climate change impacts on productivity are often overlooked. Using a forest growth model, the study analyzed future productivity and found that temperature increase can lead to significant declines in productivity across tropical lowland climate zones. High-emission scenarios could reduce reforestation effectiveness as a climate action tool.