Many of the frontier forests that have survived into this century may not make it into the next. Results from this study suggest that 39 percent of the world's remaining frontiers are threatened -- that is, under moderate or high threat -- by logging, agricultural clearing, and other activities, often along the forest edges. Many frontier forests not yet threatened -- particularly those in the tropics -- are still
vulnerable because they contain valuable timber, oil, or minerals.
Most of the safest frontier forests are in the far north, where resource-extraction costs are high. Taking these forests out of the global calculus changes it significantly: outside Russia and Canada, three quarters of the world's frontier forests -- including virtually all temperate forest frontiers -- are at risk. The most important threats to frontier forests are described below:
- Logging: This study suggests that commercial logging poses by far the greatest danger to frontier forests. In all six regions assessed, WRI's advisors cited logging as the predominate threat to forests -- affecting more than 70 percent of the world's threatened frontiers. (See Threats to Frontier Forests) Logging can significantly "rewrite" the structure and composition of forests. Yet, some of its most negative effects are indirect: logging offsets the cost of road-building to extract the timber, which in turn opens forests to hunting, fuelwood gathering, and clearing for agriculture. Widely considered the primary cause of tropical deforestation (when frontier and non-frontier forest are taken together), agricultural clearing, in particular, is hastened once loggers open forests up. [30][31]
Energy development, mining, and new infrastructure: Large-scale mining and exploration for petroleum and natural gas also bring new roads and settlements that open once-inaccessible forests to other human activities. Damming rivers for hydroelectric power floods millions of hectares of forest and disrupts freshwater ecosystems. These operations also take up forest land and spew pollution into the environment. Energy development, mining, and the roads, pipelines, and settlements that come with it represent the second biggest threat to frontier forests globally, affecting close to 40 percent of all frontiers classified as under moderate or high threat.
Land clearing for agriculture: One fifth of the world's threatened frontiers are directly endangered by farmers who clear forest for cropland and pasture. Land clearing is particularly rapacious in Asia, Africa, and Latin America. This threat can only grow as population increases. For the record, results from WRI's study suggest that non-frontier forests -- often criss-crossed by roads and easily accessible -- are under much greater pressure from farmers than are frontier forests.
Excessive vegetation removal: Apart from logging and outright clearing, humans are removing millions of tons of vegetation from frontier forests, pulling at the fabric of these ecosystems. WRI found that about 14 percent of the world's threatened frontiers are being degraded by overgrazing or the overcollection of firewood, building materials, and other vegetation. Besides damaging terrestrial habitats, excessive vegetation removal causes the rivers and streams that run through these forests to silt up.
Overhunting: As ecosystems, frontier forests comprise more than just trees. Local extinctions of animal species can affect the integrity of the entire forest. Many species -- including elephants in Africa and beaver in North America -- distribute tree seeds and otherwise shape forest structure. In Africa, one third of the forest frontier which is threatened is at risk through commercial hunting, driven largely by urban demand for bushmeat.
Other threats: On a smaller scale, other activities also endanger frontier forests. They range from the obvious -- forest conversion to, say, tree plantations or ski resorts -- to the not so obvious. Among the latter are forest managers who suppress natural fires which help shape many frontier ecosystems, far-off factories that emit wind-borne pollutants harmful to trees, and exotic animal species introduced either accidentally or deliberately by people who don't know or don't care that the newcomers can outcompete native plants and animals for scarce resources. (In New Zealand, our advisors concluded that introduced and feral species -- domestic species gone wild -- pose the single greatest danger to frontier forests.)
In most cases, frontier forests are endangered by more than one of these threats. One future threat not covered in this study is the potential impact of global warming on forest ecosystems. Native species that can't adapt or migrate to new habitats quickly enough could die out rapidly as climate changes and new diseases, pest infestations, and natural disturbances increase as a result. [32]
