China's Planted Forests Show Early Carbon Uptake Decline in Drylands: 20-Year Study

China's Yellow River Basin gained roughly 35,000 square kilometers of planted forest over three decades, but a new study in Scientific Reports shows that carbon uptake begins declining within 15 years in over 80% of those areas. The research, based on 20 years of monitoring data from 2001 to 2019, found that net primary productivity shifted from increasing to declining early in most planted forests, with nearly half declining within a decade. The main constraint is water availability, as drought and soil moisture limits curb the long-term carbon sequestration potential of these dryland plantations. The findings challenge assumptions that more trees automatically mean more carbon storage. While initial afforestation boosted NPP by 34%, it later dropped by 10%. Soil organic carbon also increased but at a slowing rate. The researchers recommend more strategic spatial planning, native vegetation, and greater consideration of grassland restoration in water-limited areas. For carbon markets and climate policy, this means baselines for afforestation projects need to account for early saturation and water limits, not just tree age or area planted.