Dynamics of forest biomass carbon stocks from 1949 to 2008 in Henan Province, east-central China

Abstract

We estimated forest biomass carbon storage and carbon density from 1949 to 2008 based on nine consecutive forest inventories in Henan Province, China. According to the definitions of the forest inventory, Henan forests were categorized into five groups: forest stands, economic forests, bamboo forests, open forests, and shrub forests. We estimated biomass carbon in forest stands for each inventory period by using the continuous biomass expansion factor method. We used the mean biomass density method to estimate carbon stocks in economic, bamboo, open and shrub forests. Over the 60-year period, total forest vegetation carbon storage increased from 34.6 Tg (1 Tg = 1 × 1012 g) in 1949 to 80.4 Tg in 2008, a net vegetation carbon increase of 45.8 Tg. By stand type, increases were 39.8 Tg in forest stands, 5.5 Tg in economic forests, 0.6 Tg in bamboo forests, and −0.1 Tg in open forests combine shrub forests. Carbon storage increased at an average annual rate of 0.8 Tg carbon over the study period. Carbon was mainly stored in young and middle-aged forests, which together accounted for 70–88% of the total forest carbon storage in different inventory periods. Broad-leaved forest was the main contributor to forest carbon sequestration. From 1998 to 2008, during implementation of national afforestation and reforestation programs, the carbon storage of planted forest increased sharply from 3.9 to 37. 9 Tg. Our results show that with the growth of young planted forest, Henan Province forests realized large gains in carbon sequestration over a 60-year period that was characterized in part by a nation-wide tree planting program.