China's terrestrial ecosystems have functioned as important carbon sinks. Although there have been several studies on the carbon pools of China’s terrestrial ecosystems, large uncertainties remain due to the limitations of sample size, multiple data sources, and inconsistent methodologies.

Research group led by Prof. FANG Jingyun from the Institute of Botany, Chinese Academy of Sciences, has been studying the carbon pool/sink of China's terrestrial ecosystems for a long time.

Recently, this group, in collaboration with Prof. ZHOU Guoyi from South China Botanical Garden, has conducted an intensive field campaign to investigate all sectors of carbon stocks in China's forests, shrublands, grasslands, and croplands, to better estimate the regional and national carbon pools and to explore the biogeographical patterns and potential drivers of these pools.

The total carbon pool in these four ecosystems was 79.24±2.42 Pg C, of which 82.9% was stored in soil (to a depth of 1 m), 16.5% in biomass, and 0.60% in litter.

Forests, shrublands, grasslands and croplands contained 30.83±1.57 Pg C, 6.69±0.32 Pg C, 25.40±1.49 Pg C, and 16.32±0.41 Pg C, respectively. When all terrestrial ecosystems are taken into account, the country's total carbon pool is 89.27±1.05 Pg C.

The results update the estimates of carbon pools in China's terrestrial ecosystems based on direct field measurements, and these estimates are essential to the validation and parameterization of carbon models in China and globally.

The carbon density of the forests, shrublands, and grasslands exhibited a strong correlation with climate: it decreased with temperature but increased with precipitation.

The country's forests have a large potential of biomass carbon sequestration of 1.9–3.4 Pg C in the next 10 to 20 years assuming no removals.

These findings provide a benchmark to identify the effectiveness of the government's natural protection policies.

As one of seven papers within the special feature titled "climate change, human impacts, and carbon sequestration in China" in the journal PNAS, the results were published entitled "Carbon pools in China’s terrestrial ecosystems: new estimates based on an intensive field survey".

This work was supported by funds from the Strategic Priority Research Program of the Chinese Academy of Sciences and the National Natural Science Foundation of China.