Afforestation has long been taken as a useful method to protect landscape from sand erosion and restore ecology environment, especially in arid and semi-arid areas. What is the effectiveness of afforestation? A recent study by Chinese scientists may find the answer.

After meta-analysis of previous studies, a research team led by LI Lanhai from Xinjiang Institute of Ecology and Geography (XIEG) of the Chinese Academy of Sciences found that afforestation significantly increased the soil organic carbon (SOC) and total nitrogen (TN) stocks.

"The results showed that overall, afforestation significantly increased SOC stock by 131% and TN stock by 88%," said LI.

Arid and semi-arid regions store approximately 27% of global SOC, and therefore play an important role in global carbon cycle.

Their study found that prior land-use is the most important factor that influences the dynamics of SOC and TN stocks following afforestation. Importantly, larger increases in SOC and TN stocks were observed after barren land afforestation in comparison to cropland and grassland afforestation, according to LI.

The researchers also showed that the broadleaf deciduous forests have a better performance than coniferous forests or broadleaf evergreen forests on accumulation of SOC and TN stocks after afforestation.

"This may provide scientific basis for the soil fertility restoration and improvement in arid and semi-arid regions, and shed light on the development of effective carbon sequestration and mitigation measures," said LI.

The study was published in Science of The Total Environment with the title "Dynamics of soil carbon and nitrogen stocks after afforestation in arid and semi-arid regions: A meta-analysis".