As climate change intensifies, extreme drought events are becoming more frequent and severe, posing threats to forest stability and carbon storage capacity. However, the relative importance of climatic background and intrinsic tree growth strategies in shaping drought resilience remains unresolved, especially in monsoon-dominated tropical and subtropical regions.

In a study published in Agricultural and Forest Meteorology, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences and their collaborators investigated the growth resilience and recovery dynamics of four widely distributed pine species across Southeast Asia under extreme drought conditions. Their findings reveal that drought sensitivity and tree growth traits, rather than long-term climate averages, are the primary drivers of how these pines withstand and recover from severe dry spells.

The researchers compiled a comprehensive treering width dataset from 103 sites, covering four pine species widespread in the region. They measured drought resistance (growth during drought year relative to pre-drought mean), recovery (post-drought growth relative to drought-year growth), and overall resilience (post-drought growth relative to pre-drought growth) to assess how trees respond to extreme early growing-season droughts.

Using advanced analytical tools, including random forest modelling, the researchers found that drought sensitivity was the strongest predictor of both resistance and recovery, followed by growthrelated traits. Climatic variables consistently ranked lowest in explanatory power.

Across all four species, early-season moisture availability emerged as the dominant constraint on radial growth. While extreme drought severely reduced growth in all species, most trees regained average growth levels within three years, with marked interspecific differences. Notably, Pinus yunnanensis exhibited the lowest resistance but the highest recovery capacity. In contrast, Pinus kesiya showed the slowest recovery and the lowest overall resilience, while Pinus latteri combined strong drought resistance with rapid recovery.

The study also uncovered a clear tradeoff: sites with higher drought sensitivity tended to experience greater growth reductions during drought but demonstrated stronger post-drought recovery. This pattern reflects fundamental physiological trade-offs in carbon allocation and water use regulation.

“Our results suggest that forest growth assessments based primarily on mean climatic conditions may underestimate post-drought recovery in monsoon-dominated regions, unless seasonal drought timing, tree attributes, and growth sensitivity are explicitly accounted for,” said Dr. FAN Zexin of XTBG.

The researchers emphasized that compared to unchangeable climatic backgrounds, selecting specific size classes or less sensitive species for afforestation could serve as effective approaches to enhance forest drought resilience.

Pine forest in Yunnan. (Image by YANG Raoqiong)

Available online: 7 July 2026