China's fight to halt tree cover loss

Abstract

China is investing immense resources for planting trees, totalling more than US$ 100 billion in the past decade alone. Every year, China reports more afforestation than the rest of the world combined. Here, we show that China's forest cover gains are highly definition-dependent. If the definition of ‘forest’ follows FAO criteria (including immature and temporarily unstocked areas), China has gained 434 000 km2 between 2000 and 2010. However, remotely detectable gains of vegetation that non-specialists would view as forest (tree cover higher than 5 m and minimum 50% crown cover) are an order of magnitude less (33 000 km2). Using high-resolution maps and environmental modelling, we estimate that approximately 50% of the world's forest with minimum 50% crown cover has been lost in the past approximately 10 000 years. China historically lost 1.9–2.7 million km2 (59–67%), and substantial losses continue. At the same time, most of China's afforestation investment targets environments that our model classes as unsuitable for trees. Here, gains detectable via satellite imagery are limited. Conversely, the regions where modest gains are detected are environmentally suitable but have received little afforestation investment due to conflicting land-use demands for agriculture and urbanization. This highlights the need for refined forest monitoring, and greater consideration of environmental suitability in afforestation programmes.

A New Opportunity to Recover Native Forests in China

“…Government statistics subsequently reported rapid increases in China's forest cover starting from the late 1990s (Figure ), although alternative assessments indicated that the increases were not as significant (Ahrends et al . ) or may even have been negative (China Nature Watch ). Regardless of the extent of increase, however, China's forests created via reforestation programs are overwhelmingly monocultures or compositionally simple forests (Xu ; Zhai et al .…”

“…Note that alternative assessments indicate that recent increases in China's forest cover are not as significant as government statistics suggest (Ahrends et al . ) or may even have been negative (China Nature Watch ).…”

“…; Ahrends et al . ; China Nature Watch ; Figure ). Yet, the ecological values of native forests cannot be overemphasized, particularly in comparison to monocultures and other compositionally simple forests, and especially with respect to biodiversity conservation (Bremer & Farley ; Gibson et al .…”

“…A system of nationwide and regional programs aimed at forest conservation and reforestation was swiftly initiated (Chapter 1 in Yin 2009) on an unprecedented scale. Government statistics subsequently reported rapid increases in China's forest cover starting from the late 1990s (Figure 1), although alternative assessments indicated that the increases were not as significant (Ahrends et al 2017) or may even have been negative (China Nature Watch 2017). Regardless of Data on total forest cover are from the National Forest Inventory (since 1976), which has taken place approximately every 5 years since 1976, and from He et al 2007He et al (prior to 1976.…”

More than half the Earth

“…The choice of China as a location is appropriate given that it has conducted the largest afforestation programme of any country in an attempt to mitigate climate change. However, the devil is -as ever -in the detail, with the extent and quality of forest cover depending very much on definitions, and a considerable amount of afforestation occurring in areas that are of debateable suitability 3 . Something that could be of great benefit to effective tree-planting programmes is an improved understanding of the relationship between forest functions and biodiversity, and a study in this issue uses data from an Asian site to address such a question.…”