Recent tree cover increases in eastern China linked to low, declining human pressure, steep topography, and climatic conditions favoring tree growth

Abstract

Globally, the extent of forest continues to decline, however, some countries have increased their forest extent in recent years. China is one of these countries and has managed to increase their tree cover through huge reforestation and afforestation programs during recent decades as well as land abandonment dynamics. This study investigates tree cover change in the eastern half of China between 2000 and 2010 on three different scales, using random forest modeling of remote sensing data for tree cover in relation to environmental and anthropogenic predictor variables. Our results show that between the years 2000 and 2010 2,667,875 km2 experienced an increase in tree cover while 1,854,900 km2 experienced a decline in tree cover. The area experiencing ≥10% increase in tree cover is almost twice as large as the area with ≥10% drop in tree cover. There is a clear relation between topography and tree cover change with steeper and mid-elevation areas having a larger response on tree cover increase than other areas. Furthermore, human influence, change in population density, and actual evapotranspiration are also important factors in explaining where tree cover has changed. This study adds to the understanding of tree cover change in China, as it has focus on the entire eastern half of China on three different scales and how tree cover change is linked to topography and anthropogenic pressure. Though, our results show an increase in tree cover in China, this study emphasizes the importance of incorporating anthropogenic factors together with biodiversity protection into the reforestation and afforestation programs in the future.

Snub-nosed monkeys (Rhinopithecus): potential distribution and its implication for conservation

“…Li et al (2002) provide evidence that Rhinopithecus was first extirpated from lower elevation during the last 400 years. Higher elevation areas are more remote and difficult for humans to access and utilize and other studies have found less deforestation, more reforestation and afforestation, less range contraction, and less extinction in topographically steep areas (Laliberte and Ripple 2004; Fisher 2011; Sandel and Svenning 2013; Faurby and Svenning 2015; Nüchel and Svenning 2017). Furthermore, many other species in the region, e.g., giant panda ( Ailuropoda melanoleuca ) and red panda ( Ailurus fulgens ), have also been impacted by strong anthropogenic pressure during the recent centuries with population declines and range retractions as consequences (Ceballos and Ehrlich 2002; Zhu et al 2010; Hu et al 2011).…”

“…This also means that there is a high probability that many of the regions’ threatened species are refugee species, confined to suboptimal habitat. On the other hand, it should be noted that there are large reforestation and afforestation programs going on in China, especially since end of 1990s (Yin et al 2005; Zhang and Song 2006; Peng et al 2014; Nüchel and Svenning 2017). …”

Stability in subtropical forests: The role of tree species diversity, stand structure, environmental and socio‐economic conditions

“…During the 2000–2015 period, because of higher human population density and urbanization, forests in hilly areas were usually associated with higher demand for forest natural resources (e.g., food, fibre and fuel) for developed lands and transportation infrastructure compared with forests in mountainous areas. In contrast, many mountainous areas that have experienced a decline in population density and an increase in tree cover (a proxy for productivity) appeared in the areas with marginal farmlands abandoned in recent years, in particular, in mountainous areas with steep slopes, attributable to rural‐to‐urban migration in China (Nüchel et al., 2019; Nüchel & Svenning, 2017).…”

Forest Fire Risk Estimation in a Typical Temperate Forest in Northeastern China using the Canadian Forest Fire Weather Index, Case of Autumn 2019 and 2020

“…Forest fires are the most widespread and critical disturbance in boreal and temperate forest ecosystems (Ying et al 2018). While China's forest cover has increased by about 10% as a result of sustainable forest management since the late 1970s (Nöchel and Svennin 2017), the forest area ecosystems affected by fire is increasing at the alarming rate of roughly 600 thousand hectares per year (Yang et al 2010). Climatic conditions and forest composition in northeast China, much like those in the United States of America, Canada, Australia, and Mediterranean Europe, are favourable to forest fires.…”