Human influence on the temporal dynamics and spatial distribution of forest biomass carbon in China

Abstract

Global carbon cycles are impacted by human activity primarily via fossil fuel combustion and forest carbon budget alterations. In this study, the temporal dynamics and spatial distribution of forest biomass carbon (FBC) stock and density in China were analyzed to assess the large‐scale effects of humans on FBC. The results indicated that from 1977 to 2013, the FBC stock increased by 62.9%, from 4,335 to 7,064 Tg C, owing to human‐driven forestation and ecological restoration programs. Because of intensive human impacts, 44.2%–54.6% of the FBC stock was concentrated in four provinces (Heilongjiang, Yunnan, Inner Mongolia, and Sichuan) and the FBC density increased from the densely populated southeastern provinces to the sparsely populated northeastern and western provinces. On a spatial scale, the FBC density was significantly negatively related to population density, and the degree of the dependence of the FBC density on population density has been declining since 1998. This improvement in human–forest relations is related to economic development and programs in China that have promoted forestation and reduced deforestation. These results suggest that human impacts, including forestation, deforestation, population density, and economic development, have played significant roles in determining the temporal and spatial variations of FBC in the anthropogenic era. Moreover, our findings have implications for forest management and improvement of the forest carbon sink in China.

Migration of Rural Residents to Urban Areas Drives Grassland Vegetation Increase in China’s Loess Plateau

“…In the forest-grassland zone, the increase in urbanization rate led to the decrease in grassland vegetation AGB and area ( Figure 3e); this finding is consistent with the results of studies on forest biomass carbon or terrestrial NPP [46,75]. However, the increase in urbanization rate would promote the increase of grassland vegetation in the other three bioclimatic zones (Figure 3b-d).…”

“…Thus, in the present study, over 20-year data on 22 counties were analyzed to evaluate the responses of grassland vegetation dynamics to human activities (i.e., population change, urbanization, agricultural production, and economic development) and climate change (i.e., precipitation, temperature, and sunshine) in the Loess Plateau ( Figure 1b). We focused on these factors because of the following reasons: (1) temperature and water resources are regarded as the controlling factors driving the seasonal variation of vegetation growth in arid and semi-arid areas [43,44]; (2) urbanization, population density, agricultural production, and economic development are the key human drivers of ecosystem structure and function [45][46][47][48]. Similar to those in other developing countries, rural areas account for the vast majority of China's Loess Plateau.…”

Effects of national ecological restoration projects on carbon sequestration in China from 2001 to 2010

“…Second, despite only occupying 18.4% of the total national land area, these two regions currently feed 57.6% of China's population and provide 62% of the national GDP (22). Therefore, the higher population density in these regions increases the land demand for agriculture and housing construction and results in higher economic costs for the local implementation of large-scale ecological restoration projects (23).…”

Spatial Pattern of Forest Carbon Storage in the Vertical and Horizontal Directions Based on HJ-CCD Remote Sensing Imagery

“…The carbon sequestration rate of vegetation in coniferous forests is not as high as that of vegetation in broadleaf forests (Table 3) but is stable and persistent. Hence, the carbon density of coniferous forests is higher than that of broadleaf forests [39,42]. Meanwhile, coniferous forests are extensively distributed in Hubei Province and accounts for 71.35% of the total forest area of the province.…”

“…This result is mainly because the forests in Hubei Province are mainly distributed in the west, and most of the forests are in the west for three main reasons. Firstly, the western mountainous region of Hubei Province is China's transition zone between the second and third terrain ladders and mainly includes the Wudang Mountains and the Daba Mountains, which consist of Shengnongjia, the Jing Mountain and the Wu Mountain [40][41][42]. These areas have had little interference from human activities and changes in the distribution of the original forest [43,44].…”