Deforestation has fallen in Congo Basin countries over the past decade despite a sharp increase in the rate of forest clearing in the Democratic Republic of the Congo, according to a new study published in the Philosophical Transactions of the Royal Society B as part of a set of 18 papers on the region’s tropical forests.
The special issue, which was put together by Yadvinder Malhi, Stephen Adu-Bredu, Rebecca Asare, Simon Lewis and Philippe Mayaux, covers a range of issues relating to the rainforests of the Congo Basin, including deforestation, the impacts of global change, the history and key characteristics of the region’s forests, and resource extraction, among others.
With 178 million hectares of rainforests, the Congo Basin is second only to the Amazon in terms of tropical forest cover. Overall the region accounts for 89 percent of Africa’s tropical rainforests and stores 39 billion tons of carbon, accounting for 79 percent of the continent’s terrestrial carbon.
Congo deforestation on the decline
Analysis of satellite data by Philippe Mayaux and colleagues shows the Congo Basin — at 0.3 percent annual forest loss — has the lowest deforestation rate of the planet’s major tropical forest regions, both in proportional and absolute terms. The region’s deforestation rate is also declining, falling 36 percent from 285,400 hectares a year in the 1990s to 181,500 ha per year in the 2000s. Africa’s overall rate of rainforest loss is outpacing that of the Congo, falling more than half from 592,000 ha in the 1990s to 288,000 ha per year during the past decade.
The special issue notes that Africa’s relative low rate of forest loss is a product of its circumstances, including “the almost complete absence of agro-industrial scale clearing”, which globally accounts for more than half of tropical forest loss. Thomas Rudel of Rutgers University analyses drivers of deforestation in the region and finds that oil and mineral wealth seem to be acting as a deterrent to deforestation by triggering urban migration away from forest areas. But at the same time, this shift appears to weakening food security by increasing countries’ dependence on food importance.
“The wetter Congo basin countries had lower rates of deforestation, in part because tax receipts from oil and mineral industries in this region spurred rural to urban migration, declines in agriculture and increased imports of cereals from abroad,” writes Rudel. “In this respect, the Congo basin countries may be experiencing an oil and mineral fueled forest transition.”
The research found most deforestation is “found around transport networks and close to cities, including areas suitable for agriculture within 5 hours travel time to major markets, and wood fuel and charcoal provisioning within 12 hours from a city.”
But unlike other parts of the world, research published in the special issue suggests that commercial logging does not appear to be a major driver of deforestation in the Congo Basin. Instead it drives forest degradation and is associated with the burgeoning bushmeat trade by granting access via logging roads to hunters.
“In the high diversity African tropics, there are typically only one to two timber trees harvested per hectare, and it makes little economic sense to clear cut forests remote from markets,” write Malhi and colleagues. “This contrasts with Southeast Asia, where the dipterocarp-rich forests yield many more timber species, and are much more intensively logged (around 10–20 trees per hectare) and heavily damaged by logging.”
“Mayaux et al and Rudel explore the possible linkages between logging and subsequent deforestation. They find little evidence of logging leading to deforestation, either at national or local scales. One key difference from Amazonia is the lack of an active colonization frontier with pressure to clear logged forest. The loose network of logging tracks, owing to the light exploitation density, combined with the low population density, does not provoke the critical conditions for deforestation, except around a few concessions in the DRC.”
Another paper in the special issue looks specifically at the effects of logging on the structure and dynamics of the forest. Sylvie Gourlet-Fleury and colleagues found that while biomass and forest function rebounds quickly from logging within 25 years, commercial trees take “much longer” to recovery. Meanwhile, a review by Kate Abernethy reveals that “defaunation” from unsustainable hunting can have persistent, long-term impacts on forest structure by reducing the abundance of key seed dispersers and “forest architects” like elephants.
Elephants may have an outsized role in Congo Basin forests. As noted by Simon Lewis and others, elephants may be partly responsible for the region’s tall trees and high biomass, by crushing and eating small trees.
“The extremely low stem density in African forests may relate to the very high large animal biomass: elephants (Loxodonta africana cyclotis), gorillas (Gorilla gorilla gorilla) and other large herbivores such as bongos (Tragelaphus eurycerus) may keep the density of small trees very low,” Lewis and colleagues write. “This view is reinforced by a recent paper from Southeast Asia showing a large increase in sapling density when the large animal fauna is extirpated.”
Lewis and co-authors note that, on average, Congo forests are taller and less diverse than Asia or the Amazon. But they store nearly as much carbon as the great Dipterocarp forests of Borneo.
The great unknown for Congo forests: climate change
While Congo Basin forests appear to be absorbing more carbon at present, the science on the impact of climate change in the region is far from settled. Climate models agree that the Congo basin will see a sharp rise in temperatures — up to 4°C this century, but it is uncertain how vegetation and wildlife will respond to the new conditions. Furthermore, parts of the basin may see shifts in precipitation patterns, including “wetting of the eastern regions” and “intensified dry seasons in the western Congo Basin”. Reconstructions of past vegetation cover in the region shows that Congo forests have waxed and waned with climate change, including a “substantial” retreat 3,000 years ago.
Richard Washington and colleagues note that part of the problem in predicting the effects of climate change in the Congo Basin is lack of understanding of current conditions.
“The Congo Basin is poorly studied because of the dearth of available ground-based climate observations from the region, particularly in the past few decades,” write Malhi and colleagues. “This deficiency is of global significance, because the Congo Basin is the second most important convective ‘engine’ of the global atmospheric circulation after the Maritime Continent (insular Southeast Asia and the surrounding waters) and is also the region of highest lightning strike frequencies on the planet . In transition seasons (March–May and September–November), the Congo Basin dominates global tropical rainfall.”
Comparison of the satellite images and forest-cover maps over the region of Lisala-Bumba (DR Congo). (a) MODIS color composite; (b) Landsat color composite; (c) MODIS-derived map (Mayaux et al 2013 study); (d ) Landsat-derived map; (e) GlobCover map and ( f ) synthesis map.
Planning for the future
Given the importance of Congo forests, the special issue includes papers on conservation options in the region. Unsurprisingly, a big focus is the Reducing Emissions from Deforestation and Degradation (REDD+) mechanism, a program that aims to provide performance-based compensation to tropical countries for protecting their forests. REDD+ could potentially trigger the flow of hundreds of millions of dollars a year to Congo Basin countries, but has yet to overcome significant technical, economic, and political challenges. Nonetheless, some $550 million has already been committed to REDD+ in the region, which the issue suggests “may already be having an impact on slowing down deforestation and degradation activities in the region.”
Malhi and colleagues note that there may be a limited window for consolidating conservation gains in the region given rising interest in industrial agriculture, especially oil palm plantations.
“A major threat to the forest biome is the potential of a shift to commercial agro-plantations, the write. “If poorly planned, then these industrial croplands could lead to extensive loss of forests as witnessed in Southeast Asia, and in soya bean regions of Amazonia, especially when combined with poor governance.”
Rainforest logs in Gabon
Need for more research
The special section ends with a call to better understand Congo Basin forests.
“This short synthesis has highlighted many surprising aspects of the African rainforest biome, and how different it is in many aspects from other, perhaps better understood, rainforest regions. It has also highlighted how little we know and how much there is still to discover,” write Malhi and colleagues. “There are reasons for concern, such has the heavy levels of defaunation and the potential impacts of climate change, and reasons for hope, such as the low rates of deforestation and the possible resilience of rainforest species to climate change.”
“We call on the research and policy communities to redouble efforts to give this fascinating rainforest continent the attention it so richly deserves.”
Young gorilla in Gabon
PAPERS IN THE SPECIAL ISSUE:
- Malhi, Yadvinder; Adu-Bredu, Stephen; Asare, Rebecca; Lewis, Simon; Mayaux, Philippe. Introduction: The past, present and future of Africa’s rainforests
- Mayaux, Philippe; Pekel, Jean-François; Desclée, Baudouin; Donnay, François; Lupi, Andrea; Achard, Frédéric; Clerici, Marco; Bodart, Catherine; Brink, Andreas; Nasi, Robert; Belward, Alan. State and evolution of the African rainforests between 1990 and 2010
- Lewis, Simon et al. Aboveground biomass and structure of 260 African tropical forests
- Mitchard, Edward; Flintrop, Clara. Assessing the relative magnitude of woody encroachment and deforestation in sub-Saharan Africa’s woodlands and savannas 1982-2006
- Rudel, Thomas. The National Determinants of Deforestation in Sub-Saharan Africa
- Oslisly, Richard; White, Lee; Bentaleb, Ilham; Favier, Charly; Fontugne, Michel; Gillet, Jean François; Sebag, David. Climatic and cultural changes in the West Congo Basin forests over the past 5000 years
- Willis, Katherine; Bennett, Keith; Burrough, Sallie; Macias-Fauria, Marc; Tovar, Carolina. Determining the response of African biota to climate change: using the past to model the future
- Abernethy, Kate; Coad, Lauren; Taylor, Gemma; Lee, Michelle; Maisels, Fiona. Extent and ecological consequences of hunting in Central African rainforests in the 21st Century
- Gourlet-Fleury, Sylvie; Mortier, Frédéric; Fayolle, Adeline; Baya, Fidèle; Ouedraogo, Dakis; Benedet, Fabrice; Picard, Nicolas. Tropical forest recovery from logging: a 24 year silvicultural experiment from Central Africa
- Fisher, Joshua; Sikka, Munish; Sitch, Stephen; Ciais, Philippe; Poulter, Benjamin; Galbraith, David; Lee, Jung-Eun; Huntingford, Chris; Viovy, Nicolas; Zeng, Ning; Ahlström, Anders; Lomas, Mark; Levy, Peter; Frankenberg, Christian; Saatchi, Sassan; Malhi, Yadvinder. African tropical rainforest net CO2 fluxes in the 20th century
- James, Rachel; Washington, Richard; Rowell, David. Implications of global warming for the climate of African rainforests
- Washington, Richard; James, Rachel; Pearce, Helen; Pokam, Wilfried; Moufouma-Okia, Wilfran. Congo Basin rainfall climatology: can we believe the climate models?
- Otto, Friederike; Jones, Richard; Halladay, Kate; Allen, Myles. Attribution of changes in precipitation patterns in African rainforests
- Asefi-Najafabady, Salvi; Saatchi, Sassan. Response of African humid tropical forests to recent rainfall anomalies
- Maniatis, Danae; Gaugris, Jerome; Mollicone, Danilo; Scriven, Joel; Corblin, Alexis; Ndikumagenge, Cleto; Aquino, André; Crete, Philippe; Sanz-Sanchez, Maria-José. Financing and current capacity for REDD+ readiness and monitoring, measurement, reporting and verification in the Congo Basin
- Asare, Rebecca. The Community Resource Management Area Mechanism: A strategy to manage African forest resources for REDD+
- Gond, Valery; Fayolle, Adeline; Pennec, Alexandre; Cornu, Guillaume; Mayaux, Philippe; Camberlin, Pierre; Doumenge, Charles; Fauvet, Nicolas; Gourlet-Fleury, Sylvie. Vegetation structure and greenness in central Africa from modis multi-temporal data
- Malhi, Yadvinder; Adu-Bredu, Stephen; Asare, Rebecca; Lewis, Simon; Mayaux, Philippe. African rainforests: past, presents and future
(07/23/2013) Unsustainable hunting of forest elephants, gorillas, forest antelopes, and other seed-dispersers could have long-term impacts on the health and resilience of Congo Basin rainforests, warns a study published today in a special issue of the journal Philosophical Transactions of The Royal Society B. Conducting a review of more than 160 papers and reports on trends in wildlife populations, hunting, and land use in the Congo Basin, an international team of researchers conclude that unless effective management plans are put into place, hunting pressure in the region is likely to increase, with knock-on ecological effects.
(06/06/2013) The Cameroonian government has lifted the suspension on controversial palm oil project in the northwestern part of the Central African nation, reports the AFP.
(11/08/2012) In 2002 the Democratic Republic of Congo (DRC) announced a moratorium on commercial logging in a bid to save rapidly falling forests, however a new report by Global Witness alleges that industrial loggers are finding a way around the logging freeze. Through unscrupulous officials, foreign companies are abusing artisanal permits—meant for local community logging—to clear-cut wide swathes of tropical forest in the country. These logging companies are often targeting an endangered tree—wenge (Millettia laurentii)—largely for buyers in China and Europe.
(06/20/2012) This summer, the Democratic Republic of Congo (DRC) is expected to approve a new higher education strategy which the country has developed with the World Bank and other international donors. The shape of this educational reform initiative will be critical to Congo’s future in many ways. It could finally offer Congo’s long-suffering people a route into the 21st century. It will also help determine the future of the DRC’s forests. Nearly half of the Congo Basin’s remaining rainforest is in the DRC—yet the critical role of Congolese experts in forestry, agricultural science, wildlife management and other rural sciences in protecting this forest is not widely recognized.
(03/20/2012) Deforestation in the Congo Basin has increased sharply since the 1990s, reports an extensive new assessment of forests in the six-nation region. Released by the Central African Forests Commission (COMIFAC) and members of the Congo Basin Forest Partnership, The State of the Forest finds that the region’s annual gross deforestation rate doubled from 0.13 percent to 0.26 percent between the 1990s and the 2000-2005 period. Gross degradation caused by logging, fire, and other impacts increased from 0.07 percent to 0.14 percent on an annual basis. Despite the jump, rates in the Congo Basin remain well below those in Latin America and Southeast Asia, but the region is seen as a prime target for future agroindustrial expansion.
(09/13/2011) Industrial palm oil production is coming to Africa, its ancestral home. And like other places where expansion has occurred rapidly, the crop is spurring hope for economic development while generating controversy over its potential impacts. The world’s most productive oil seed has been a boon to southeast Asian economies, but the looming arrival of industrial plantations in Africa is raising fears that some of the same detriments that have plagued leading producers Malaysia and Indonesia—deforestation, greenhouse gas emissions, biodiversity loss, conflicts with local people, social displacement, and poor working conditions—could befall one of the world’s most destitute regions. While there is no question that oil palm is a highly lucrative crop that can contribute to economic development, there is also little doubt that conversion of native forests for plantations exacts a heavy toll on the environment. The apparent conflict seems to pit agroindustrial goliaths against greens, with communities falling somewhere in between. But Herakles, a New York-based investment firm planning to construct a 60,000-hectare plantation in the Central African country of Cameroon, says its approach will bridge this gap between economic development and the environment. Social and environmental campaigners are skeptical.
(06/22/2011) Forests in sub-Saharan Africa account for roughly a quarter of total tropical forest carbon, according to a comprehensive assessment of the world’s carbon stocks published in the journal Proceedings of the National Academy of Sciences (PNAS).
(06/19/2011) Africa’s forests are fast diminishing to the detriment of climate, biodiversity, and millions of people of dependent on forest resources for their well-being. But is the full conservation of Africa’s forests necessary to mitigate global climate change and ensure environmental stability in Africa? A new report by The Forest Philanthropy Action Network (FPAN), a non-profit that provides research-based advice on funding forest conservation, argues that only the full conservation of African forests will successfully protect carbon stocks in Africa.
(05/22/2011) Two separate protests against logging companies by local communities have turned violent in the Democratic Republic of Congo (DRC), leaving at least one dead. According to Greenpeace, one of the companies involved in the violence, Sodefor, is sustainably certified by the Forest Stewardship Council (FSC). Given that the industry in DRC is rife with social conflict and corruption, Greenpeace is advocating that FSC place a moratorium on certifying new industrial-style logging concessions in the central African nation.
(09/24/2009) Chainsaws, bulldozers, and fires are tools of rainforest destruction, but roads are enablers. Roads link resources to markets, enabling loggers, farmers, ranchers, miners, and land speculators to convert remote forests into economic opportunities. But the ecological cost is high: 95 percent of deforestation in the Brazilian Amazon occurs within 50-kilometers of a road; in Africa, where logging roads are rapidly expanding across the Congo basin, the bulk of bushmeat hunting occurs near roads. In Laos and Sumatra, roads are opening last remnants of intact forests to logging, poaching, and plantation development. But roads also cause subtler impacts, fragmenting habitats, altering microclimates, creating highways for invasive species, blocking movement of wildlife, and claiming animals as roadkill. A new paper, published in Trends in Evolution and Ecology, reviews these and other impacts of roads on rainforests. Its conclusions don’t bode well for the future of forests.