Chinese planted forests grow canopies faster than natural forests

Researchers at Peking University and the Beijing Forestry University found that planted forests in China expand their leaf area about 66 percent faster than natural forests.

The study, published in Geophysical Research Letters, used satellite data from 2000 to 2022 to track the leaf area index, which measures canopy density and carbon absorption capacity. The researchers noted that this growth advantage is primarily because planted forests are younger on average.

While the planted forests in the study averaged 34 years old, the natural forests averaged 57 years old. When the scientists compared forests of similar ages and conditions, the planted forests still showed a 4.6 percent lead in growth speed. The authors attributed the rapid growth in the first few decades to the use of fast-growing species like eucalyptus and poplar, along with human maintenance such as weeding and soil fertilization. These factors reduce competition for light and water.

However, the growth advantage begins to fade after 40 years. Yuhang Luo stated that while planted forests are a powerful short-term tool for carbon absorption, natural forests remain indispensable for long-term carbon storage. The study also considered the environmental costs of rapid reforestation. A separate study published in Earth's Future showed that changes in vegetation cover have reduced available freshwater in large parts of China.

Increased greenery leads to higher evaporation, which has depleted water in regions where a large portion of the population and arable land are located.