Forest destruction

Posted: 13 August 2004

The world's natural forests are experiencing land use change due to both proximate and underlying causes. Proximate drivers include immediate human land use activities that change forest cover in a local area. Key drivers include agricultural expansion, infrastructure development, wood extraction, climate change, fire and alien invasive species. Underlying causes result from social and institutional processes that may indirectly impact forest cover from a local, national, or international level. Prominent underlying causes include market failure and perverse incentives, corruption, inappropriate state policies and institutional failure, population pressure and poverty. In general, forest related land use changes have complex socio-economic, cultural and political foundations. One cannot assume simple and static cause-effect relationships.

Logging

Global wood consumption has tripled in the last hundred years, growing in rough tandem with world population. Commercial logging of forests has doubled in size as an industry since 1960. The UN Food and Agricultural Organisation (FAO) estimates that between five to six million hectares of tropical forest are logged annually. Logging is most damaging to forests when conducted unsustainably and contributes to deforestation in direct and indirect ways:

  • Timber concessions: Increasingly, governments seeking a quick source of capital sell their forest resources to timber companies in the form of timber concessions that allow them to log the forest for a pre-determined time. Short-term concessions can create a "cut-and-run" attitude among logging companies, encouraging them to extract as much timber as possible without regard for the long-term management of the forest.
  • Collateral damage: The mechanised equipment used to cut and haul logs can severely damage trees and other vegetation left standing after a forest has been logged. Assessments of tropical forest logging in Southeast Asia have recorded damage to 50 per cent of the residual tree cover with 40 per cent of the surrounding area crushed by bulldozers. Residual waste left to rot on the forest floor increases the risk of fires.
  • Fragmented forests: Clearing strips of forest cover can create fragments from formerly intact forest areas, exposing the moist ground cover to the penetrating tropical sun. Fragmented forests are highly susceptible to fires and provide habitats ill-suited to larger animal species that require substantial areas of unbroken forest.

    • Fragmented forest, Paragominas, Brazil © Bruce Vale
     
    Fragmented forest, Paragominas, Brazil. © Bruce Vale

  • Logging roads: Logged roads, apart from increasing soil erosion and degrading watersheds, open up forests to human settlement further threatening intact forested areas. Once the harvest is complete, loggers often remain in the forested area laying claim to the nearly-cleared land. A much larger migration of landless farmers and others seeking opportunities often follows.

    Agricultural clearing

    Over the years, researchers have identified agricultural expansion as a major factor in almost all studies on deforestation. In the 1990s, according to the United Nation's Environment Programme (UNEP), 70 per cent of total deforested areas were converted to permanent agriculture systems. Despite the compelling figure, regional differences should be noted. For example, in Latin America conversion to agriculture has been large scale and permanent whereas in Africa small-scale agricultural enterprises have predominated. In Asia, the changes have been more equally distributed between permanent agriculture and areas under shifting cultivation.

    Historically, increases in food production have been at the expense of millions of hectares of forest. With the expected clearance of additional forest land in the future for this purpose it is important to plan for this reality. However, equally important is acknowledging that technological innovations can have positive effects on forest areas and could, under certain circumstances, facilitate a transition from deforestation back to reforestation. If appropriate mechanisms are put in place to lock these gains in both developed and developing countries, this could potentially set a trend for large scale forest restoration in the future.

  • The FAO projects that by 2010 an additional 90 million hectares of land, roughly half of it now forested, will be converted to farmland in sub-Saharan Africa, Latin America and Asia.
  • Development of forested land for agriculture often undermines the sustainability of traditional farming systems. Without adequate time to recover between planting cycles, the land loses key nutrients and beneficial soil structure, lowering crop yields and increasing soil erosion. Faced with these diminishing returns, farmers abandon their fields to search for more fertile soil. In countries such as Indonesia, Guatamala and Brazil, subsistence agriculture has led to severe deforestation, soil degradation and further migration deeper into forest areas.

    Wood for fuel

    Fuelwood and charcoal - collectively called woodfuel - account for just over half of global wood production. The FAO estimates that nearly 3 billion people depend on wood as their main source of energy. Wood provides nearly all of the energy needs of sub-Saharan African nations. Fuel is also the most important end-use of wood in Asia accounting for 92 per cent of all wood harvested in South Asia and 73 per cent in Southeast Asia.

  • Fuelwood collection does not drive deforestation on the same scale as agricultural clearing, but it can severely deplete forests and other wooded areas, especially when driven by the demand from growing cities such as Bangalore in India. One in every five of that city's 5 million plus inhabitants rely on fuelwood which is brought in from as far away as 600 kms.
  • Rising demand for woodfuel poses a substantial threat to forests in countries such as Bangladesh, Nepal and Pakistan which already face a widening gap between the need for woodfuel and the sustainable supply. India, China, Thailand, Sri Lanka and Vietnam could also face critical fuelwood shortages within the next 20 years.

     

    Infrastructure development

    Infrastructure development (road construction, dams, mining, power stations, etc.) is an important proximate cause of forest-related land use change. Road construction particularly, is a key factor in triggering deforestation as it tends to open up areas of undisturbed, mature forests to pioneer settlements, logging, and occasionally unsuitable forms of agriculture. The ensuing fragmentation also increases the exposure of forests to the dangers of poaching, alien invasive species, fires and pest outbreaks.

     

    Forest fragmentation by roads in Central Africa. Image: WRI 2000
     

    In addition, the World Commission on Dams has documented the loss of forests and wildlife habitat, the loss of species populations and the degradation of upstream catchment areas due to large dams.

    Mining corporations and individual miners are also notably responsible for the clearance of large areas of forest in some countries. However, a recent study released by Center for International Forestry Research (CIFOR) entitled Oil Wealth and the Fate of the Forest: A Comparison of Eight Tropical Countries argues that in some cases increased incomes from oil and mining activities can have a macro-level effect on reducing the loss of tree cover in tropical countries.

    Alien Invasive Species

    As the global movement of people and products spreads, so does the movement of plant and animal species from one part of the world to another. When a species is introduced into a new habitat - for example, oil palm from Africa into Indonesia, Eucalyptus species from Australia into California, and rubber from Brazil into Malaysia - the alien species typically requires human intervention to survive and reproduce. Often these alien species are economically important and enhance the production of forest commodities in many parts of the world. However, in some cases species introduced intentionally become established in the wild and spread at the expense of native species, affecting entire ecosystems.

    Perhaps even worse are invasive alien species that are introduced unintentionally, such as disease organisms that can devastate an entire tree species (e.g. Dutch elm disease and chestnut blight in North America) or pests that can have a major effect on native forests or plantations (e.g. gypsy moths and long-horned beetles).

    As global trade grows, so does the threat from devastating invasive species of insect and pathogen. These could fundamentally alter natural forests and wipe out tree plantations, the latter being especially vulnerable because of their lower species diversity.

    To know more about Alien Invasive Species, visit: IUCN Species Survival Commission website

    Poverty

    Poverty is popularly cited as a principal driver of forest loss and degradation. In reality, however, the evidence for such a straight-forward relationship is weak and sometimes conflicting. The empirical evidence for the historical relationship between economic growth, a growing middle class, consumption levels and forest decline is perhaps a little better understood but also remains weak and fragmented. What is evident however is that there is a causal relationship, or more accurately several relationships, that need to be better understood. More reassuringly, there is some, yet again fragmented, evidence that no single trajectory is necessarily predetermined and that forest resources, under a range of circumstances, can be managed and used in such a way as to contribute to poverty reduction while keeping future options open to retain more and lose less forest biodiversity.

    To know more about Poverty and Conservation, visit IUCN's Forest Conservation Programme website

    Absence of good governance and rule of law

    Government policies, and how those policies are enforced, both within and outside the forest sector, also ultimately impact on forest land use change. Forest land is still all too often seen as a nationally-owned asset, irrespective of the stewardship that local communities have exercised over the same resource for many years. Inequities in titling and use rights can result in forests becoming a major source of conflict and / or illegal activity.

    While illegal logging and corruption may and often does exist because of pure criminality, it can, in some situations, be driven by inappropriate governance structures that turn legitimate concerns or entitlements into illegal activities. For example, in one Central American country in the early 1990s one of the main causes for bribery associated with log transport permits was not that loggers want to move illegally harvested trees but rather that they wanted to avoid long bureaucratic delays in attaining permission that would leave legally harvested trees deteriorating in forest loading yards.

    Related links:

    Forest Trends Global Forest Watch UN Food and Agriculture Organization Forest Resources Assessment

    World Conservation Monitoring Centre

    IUCN - Word Conservation Union

    WWF Forests for Life Programme