AsianScientist (Aug. 31, 2026) – China has planted more than 77 million hectares of forests over the past several decades as part of the world’s largest reforestation programme. The initiative has helped restore degraded landscapes, store carbon, and expand forest cover. But a new study suggests that planted forests respond to drought differently from natural forests.
The study, published in Forest Ecosystems, used satellite observations from 1990 to 2024 to investigate how planted and natural forests across China responded to two types of drought: rapid-onset “flash droughts” and longer-lasting “slow droughts.”
The researchers from Sun Yat-Sen University found a clear contrast.
“Planted forests experienced more frequent flash droughts than natural forests, averaging 7.05 events every five years compared with 5.76 in natural forests. In contrast, natural forests experienced more slow droughts, averaging 3.77 events compared with 3.25 in planted forests,” the researchers said.
The differences persisted even after researchers accounted for variations in climate. Compared with similar natural forests, planted forests showed a seven percent higher risk of flash drought but a 12 percent lower risk of slow drought.
Forest structure shapes drought resilience
The greater vulnerability of planted forests to flash droughts, and the higher frequency of slow droughts in natural forests, appeared to be linked to differences in forest structure.
Natural forests typically contain a greater variety of tree species, trees of different ages, and more complex canopy layers. Older trees often have deeper root systems that can access water stored deeper in the soil, helping forests withstand sudden moisture shortages.
Planted forests, by contrast, are often younger and less diverse, with simpler structures and shallower roots. These characteristics make them more vulnerable when moisture levels decline rapidly during heatwaves or other extreme weather events. At the same time, their lower overall biomass and water demand may help reduce vulnerability to prolonged drought.
The differences were most pronounced in China’s mid-temperate semi-humid regions and on the Tibetan Plateau, where large areas have been converted to planted forests.
Beyond planting more trees
Increasing forest area alone may not be enough to ensure long-term resilience, according to the study. Forest composition and structure are important factors to take into account.
“Management strategies that promote mixed-species forests, greater structural diversity, and more natural forest characteristics could help reduce vulnerability to rapid drought events,” the researchers suggested.
Another suggestion was that unrestricted expansion of plantations in water-limited regions should also be cautioned against. Although planted forests generally experienced fewer slow droughts, their recovery was more protracted and challenging.
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Source: Sun Yat-Sen University ; Image: Magnific
The study can be be found at: Understanding flash drought variations in China’s planted and natural forests through machine learning counterfactual analysis
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