Everyday entropy: reforesting China

Recovering forests, with deforested areas in the background in Wolong China

It is too easy to criticise China for making the same environmental choices that Britain and the US made in previous centuries.  Air quality in Beijing is hardly worse than it was in London at the height of the industrial revolution.  Equally, it is too easy to congratulate China for joining the deforestation-NIMBY club. Like Europe and the United States, China no longer tolerates internal deforestation, but, also like Europe and the US, Chinese investment is now contributing to deforestation in South America, Africa, Indonesia, and the rest of south east Asia.  In a pattern that mirrors reforestation in colonial Europe, China has found that deforestation can be exported as easily as opium, tobacco, and electronics.

It looks like a classic case of misunderstanding the relationship between a heat engine and its heat sink, imagining that the entropy of the environment can increase infinitely and indefinitely. 

In reading the reports on forest cover, it also seems somehow important that the difference between a 50 year-old tree and a 300 year-old tree isn’t readily apparent unless you are standing next to its base.  Ecologically, Ancient trees are not just fatter, and it is impossible to reestablish an old-growth forest in one human lifetime, let alone one political cycle.  We cannot hope to see successful reforestation, if it is ever achieved, so we have no way of knowing whether any of our reforestation efforts can be classified as a success.

As it is, imported timber accounts for more than half of China’s total timber supply. With the new logging ban in place, China is expected to fix its gaze abroad to meet domestic demand with even more imported timber. Already, evidence suggests that a large portion of the wood imports entering China are illegally sourced – particularly certain rosewood species from the Mekong region of Southeast Asia and, increasingly, from Africa. In addition, the limited availability of desirable species that plantations can’t supply could exacerbate the existing illegal logging issues in the Russian Far East, whose temperate forests border China’s and share many of the same species.”

At a global scale, both historical and recent tree cover loss followed clear spatial and macro-economic patterns. Spatially, losses have disproportionately affected areas with high population pressure and easy access (figure 3a; electronic supplementary material, figure S4). Consequently, today most (71%) tree cover remains within areas with lower human population pressure. In low-income countries (with a GDP per capita of less than US$ 10 000), a large fraction of tree cover still coincides with areas of high population pressure, where it is currently being lost at an alarming rate: between 2000 and 2012 approximately 25 000 km2 yr−1 (6%) (electronic supplementary material, figure S5). A slightly different picture emerges for high-income countries with a large proportion of boreal forests (electronic supplementary material, figure S6): here, there have also been substantial tree cover losses at distances of more than 1000 km from towns and in areas of very low population density, reflecting the proneness of boreal forests to natural loss dynamics (e.g. caused by fire, storm, insects and pathogenic fungi). Protected areas appeared to hold tree cover losses, but only to an extent: recent proportionate tree cover losses outside protected areas were approximately twice as high as inside (1.6 million km2 (5%) versus 94 000 km2 (2.9%); electronic supplementary material, figure S6).

The proportion of tree cover losses not compensated by within-country tree cover gains (loss/loss + gain) was highest in countries with high levels of poverty, urbanization, population growth, a high GDP reliance on agriculture and with expanding food production (figure 6; electronic supplementary material, figures S7 and S8). There was a strong continental signal whereby the fraction of uncompensated losses was particularly high in African countries. Losses appeared to be lower in SE Asia, but this hides the fact that there large amounts of natural tree cover are replaced with tree cash crops such as rapidly growing oil palm, rubber and Eucalyptus. There was a small negative correlation (R = −0.21, p ≤ 0.001, d.f. = 176) between the proportionate historical tree cover loss (per country) and the recent proportionate uncompensated loss, indicating that countries that have historically deforested their territories may now have shifted to protecting the remaining tree cover.

The global picture of tree cover losses illustrates China’s challenging situation: China has one of the world’s greatest coincidences of tree cover and people (figure 4), with 88% of China’s tree cover located in areas with more than 10 people per km2 and 33% in areas with greater than 100 people per km2. Globally, only 29% and 6% of tree cover are located in these population density classes, respectively. Our calculations showed that China also has one of the world’s highest correlations between area suitability for tree cover and for agriculture (globally R = 0.35; p ≤ 0.001, d.f. = 8 318 389; in China R = 0.73, p ≤ 0.001, d.f. = 546 123; China ranked ninth in the world in terms of this correlation), and the zone that is suitable for tree cover therefore overlaps to 84% with the zone suitable for agriculture. Finally, China has one of the world’s lowest per person areas of suitable agricultural land (approx. 3 × 10−3 km2 per person, which is less than one-third of the global average). As is the case globally, both historical and recent tree cover losses in China have mostly affected areas with high population pressures, high agricultural suitability and easy access (figure 3b). Today, most of China’s tree cover remains on sloping lands (1–10°), while in flat areas as much as approximately 90% of original tree cover may have been lost (electronic supplementary material, figure S9). Between 2000 and 2010, approximately 10 000 km2 of tree cover have been lost from large and unbroken expanses of intact natural forest areas [23] (see electronic supplementary material, Results S4), and between 2000 and 2012, almost 3000 km2 of tree cover with crown cover of 50% or more has been lost from protected areas (3.2%). This was slightly higher than the global proportionate loss from protected areas (2.9%) and similar to the proportionate loss outside protected areas in China (4%), raising concerns over protected area efficacy.”

China’s forest recovery shows hope for mitigating global climate 

China’s sweeping program to restore forests across the country is working.

The vast destruction of China’s forests, leveled after decades of logging, floods and conversion to farmland, has become a story of recovery, according to the first independent verification published in today’s Science Advances by Michigan State University (MSU) researchers.

“It is encouraging that China’s forest has been recovering in the midst of its daunting environmental challenges such as severe air pollution and water shortages,” said co-author Jianguo “Jack” Liu, Rachel Carson Chair in Sustainability and director of MSU’s Center for Systems Integration and Sustainability (CSIS).  “In today’s telecoupled world, China is increasingly connected with other countries both socioeconomically and environmentally. Every victory must be measured holistically, or we aren’t getting a true picture.”

Forests are crucial to ensuring soil and water conservation and climate regulation. The fate of forests in the world’s most populous nation has global consequences by virtue of the country’s sheer magnitude and its rapid development.

Since the beginning of the 21st Century, China has implemented the largest forest conservation and restoration programs in the world, the Natural Forest Conservation Program (NFCP), which bans logging, and in some forested areas compensates residents for monitoring activities preventing illegal timber harvesting.

The MSU scientists used a unique combination of data, including the big-picture view of NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) annual Vegetation Continuous Fields tree cover product, along with high spatial resolution imagery available in Google Earth. Then they combined data at different scales to correlate the status of the forests with the implementation of the NFCP.

And, as the Chinese government has contended, the program is working and forests are recovering, with about 1.6 percent, or nearly 61,000 square miles, of China’s territory seeing a significant gain in tree cover, while 0.38 percent, or 14,400 square miles, experienced significant loss.

“Our results are very positive for China,” said author Andrés Viña of MSU-CSIS. “If you look at China in isolation, its program is working effectively and contributing to carbon sequestration in accordance to its agenda for climate change mitigation. But on the other hand, China is not in a vacuum.”

In the future, it is important to quantify how much China’s forest gain and improved carbon sequestration may be a loss for places like Madagascar, Vietnam and Indonesia. Those are among the countries that are chopping down their forests to sell products to China. And the global increase in greenhouse gases and loss of biodiversity may have just changed addresses.

Viña noted more research is needed to document the broader impacts of forest degradation and recovery around the world. He also noted that the voracious appetite for natural resources – both timber and the agricultural products grown on converted forestland – is not just China’s issue.

“We are all part of the problem one way or another,” he said. “We all buy products from China, and China has not changed their imports and exports of wood at all. What has changed is where timber is coming from.”

Besides Viña and Liu, “Effects of conservation policy on China’s forest recovery” was written by MSU associate professor William McConnell, and CSIS PhD students Hongbo Yang and Zhenci Xu.”


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