The review of 25 years of forest management in 234 countries was conducted by Dr Sean Sloan and Dr Jeff Sayer of James Cook University, in conjunction with dozens of international researchers and the U.N. Food and Agricultural Organization.
The study found that the global deforestation rate since 2010 – 3.3 million hectares per year – is less than half that during the 1990s (7.2 million hectares per year).
This global slowdown is due to better management of tropical forests. Since 2010 the tropics lost 5.5 million hectares of forest per year, compared to 9.5 million hectares per year during the 1990s.
Sub-tropical, temperate, and boreal climatic regions had relatively stable forest areas.
Satellite data showed tropical forests degraded (damaged but not cleared) since 2000 are six times as extensive as all tropical deforestation since 1990, far more than in other climatic regions.
“While some of this tropical degradation reflects the temporary impacts of logging, the real fear is that much is the leading edge of gradual forest conversion,” Dr Sloan said.
High rates of tropical deforestation and degradation mean that tropical forests were a net emitter of carbon to the atmosphere, unlike forests of other climatic regions.
“But tropical forests are emitting only slightly more carbon than they are absorbing from the atmosphere due to regrowth, so with slightly better management they could become a net carbon sink and contribute to fighting climate change,” Dr Sloan said.
Despite growing demand for forest products, rates of plantation afforestation have fallen since the 2000s and are less than required to stop natural forest exploitation. Demand for industrial wood and wood fuel increased 35% in the tropics since 1990.
“The planting of forests for harvest is not increasing as rapidly as demand, so natural forests have to take the burden,” Dr Sloan said.
Northern, richer countries had steady or increasing forest areas since 1990. Their forests are increasingly characterised by plantations meant for harvest.
While natural forests expanded in some high-income countries, collectively they declined by 13.5 million hectares since 1990, compared to a gain of 40 million hectares for planted forests.
Dr Sloan said that investment in forest management in poorer tropical countries where management and deforestation were worst may herald significant environmental gains.
“But attention must extend beyond the forest sector to agricultural and economic growth, which is rapid in many low-income and tropical countries and which effect forests greatly,” Dr Sayer said.
Background to Study
The Food and Agricultural Organization (FAO) released the Global Forest Resources Assessment 2015 (FRA 2015) on September 7 2015. The FAO began publishing FRA reports in 1948 to assess the global state of forest resources, given concerns over shortages of forest products. The FAO has published FRA reports at regular intervals since on the basis of individual reports from countries, numbering 234 for the FRA 2015. FRA reports now survey a wide array of forest ecological functions, designations, and conditions in addition to forest areas for each country.
For the first time, the FRA 2015 report was realised by dozens of international experts who undertook independent analyses of FRA data, resulting in 13 scholarly articles published in a special issue of the journal Forest Ecology and Management (2015 volume 352).
The data and trends highlighted in these articles are a significant advance for the global scientific and conservation communities. This article constitutes one of 13 published in Forest Ecology and Management and integrates their major findings.