Central Asia, located in the heart of the Eurasian continent, has experienced significant climatic shifts in recent decades, characterized by warming and increased humidity. This trend contrasts sharply with the global pattern of drought-induced tree growth decline, making Central Asia a unique region for studying the impacts of climate change on forest ecosystems.
Alpine forests in this region are critical for regional water reserves and ecological stability and are the origins of many inland rivers such as Amu Darya and Syr Darya. Researchers from Yunnan University, China, in collaboration with international partners, used a comprehensive tree-ring network comprising 128 conifer chronologies from Central Asian alpine forests to assess tree radial growth patterns in this region. The study, published in Forest Ecosystems, reveals a significant positive trend in tree growth since the 20th century. This growth acceleration is attributed to low-latitude warming, which enhances regional temperatures and precipitation, thereby promoting tree growth.
Dr. Feng Chen, the corresponding author, explained, "Our findings indicate that warming centers in the Indian Ocean, the central-east Pacific Ocean, and the Atlantic Ocean significantly influence atmospheric circulation patterns, leading to increased moisture transport to Central Asia. This results in higher regional precipitation and improved tree growth conditions."
The study's projections, based on the Coupled Model Intercomparison Project 6 (CMIP6) and the Vaganov-Shashkin-Lite (VS-Lite) model, suggest that tree radial growth rates will continue to rise in the future. However, the projections also reveal that climate changes could become more extreme and happen more often. "The damaging risks of severe drought cannot be ignored," the study noted. Even during periods of drought and extreme weather, trees in alpine forests still managed to grow, indicating an inherent adaptive capacity. However, damages caused by extreme droughts are irreversible. Meanwhile, whether this resilience will stay sustainable under continued climate stress remains uncertain. Particularly, more severe climate scenarios may lead to decoupling signs between warming and enhanced growth.
This study provides critical insights into the dynamic relationship between climate change and tree growth in Central Asian alpine forests, offering a unique perspective on how changes in one part of the world can have far-reaching effects on ecosystems in distant regions. For better understanding and mitigating future impacts, future studies on enhanced modeling approaches and continuous climatic monitoring are required.
This study was supported by Excellent Research Group Program for Tibetan Plateau Earth System (continuation grant NSFC project No. 41988101), the National Natural Science Foundation of China (Nos. U1803341 and 32061123008), the National Key R&D Program of China (No. 2018YFA0606401), and the National Youth Talent Support Program.
