IUCN, the International Union for Conservation of Nature

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% 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.

To find out more about FCP's work on Forest Landscape Restoration, click here.

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. 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 study released by 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.

Another proximate cause of forest land use change is wood extraction from natural forests. Despite the growing importance of plantations as a source of wood supply, wood extraction in the form of commercial timber, poles, fuelwood and charcoal continues to degrade mature natural forests in many parts of the world. In the case of commercial logging, tree removal methods are frequently destructive and unsustainable. This is often the case on steep slopes and in sensitive ecosystems such as mangroves. Also, though many tropical countries in Africa, Asia and Latin America rely on logging timber for export earnings, according to World Bank estimates, illegal logging costs forest country governments at least US$ 10-15 billion a year - an amount greater that total annual development assistance for public education and health. Furthermore, a UN report attributes the severe pressure of illegal tree felling in protected areas and forests in the Central and Eastern European countries, and in the Former Soviet Union to increased poverty and to loss of traditional communist era livelihoods.

To find out more about the FCP's work on Forest Governance, click here.

Fires are a key driver of forest land use change. A United Nations Environment Programme (UNEP) study estimates that annually fires burn up to 500 million hectares of woodland, open forests, tropical and sub-tropical savannahs, 10-15 million hectares of boreal and temperate forest and 20-40 million hectares of tropical forests. Yet, fire is a paradox as while it can cause extensive ecological, economic, and social damage it can also be extremely beneficial through nutrient recycling and regeneration. For example in boreal forests, fire is a natural part of the forest cycle with some tree species, notably Lodgepole Pine and Jack Pine being able to germinate only after they have been exposed to fire. In addition, burning quickly decomposes organic matter into mineral components that cause a spurt of plant growth, and can also reduce disease in the forest. Nevertheless, forest fires in contrast have caused considerable environmental, health, economic and social damages in recent years and have been recognised as major cause of forest loss and degradation in some parts of the world. Furthermore, emissions from forest fires have also exacerbated global climate change.

To find out more about FCP's work on Forest Fires, click here.

Although many forests have proved relatively resilient to past climate changes, today's fragmented and degraded forests are more vulnerable, with up to 30% of forests likely to be affected by climate change by the year 2050 according to an IPCC report. The impacts will however be differential depending on forest type and species. For example, while enhanced photosynthesis and/or tree growth has been observed in some regions of the world, permafrost thawing in central Alaska threatens natural lowland birch forest. Higher temperatures and changes in rainfall also threaten tropical montane forests, boreal forests (see Figure 1) and Mediterranean-type, fire-prone forests. Furthermore, the effects of greenhouse gases can impact the highly species-specific phenology of forest trees, affecting the processes of budding, flowering, fruiting, leaf senescence, frost hardiness, wood quality, branching and insect susceptibility. While pest and disease infestations are part of the natural forest cycle, the risk of serious outbreaks increase with more changes in climate. In addition, extreme weather events, such as droughts and floods, pose other risks to forest ecosystems.

To find out more about FCP's work on climate change, click here.

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 find out more about IUCN's work on Alien Invasive Species, visit: IUCN Species Survival Commission website