Rates of Deforestation

Tropical deforestation was a concern to colonial powers in the 19th century, because of their reliance on the forests of their colonies to supply timber for building naval vessels. For example, British Colonial Foresters became concerned with the lack of regeneration of teak forests in Burma (now Myanmar) and initiated a reforestation program in the mid-1800s (Takeda 1992). However, global concern over tropical deforestation did not begin until the mid-20th century. Following World War II, logging increased in intensity and scale, and population pressures in tropical countries resulted in the clearing of tropical forests for agriculture. By the 1960s, scientists began to recognize that the disappearance of tropical forests represented an important loss of global resources, and in the 1970s and 1980s began to determine the area of tropical forests worldwide and the rate at which they were disappearing (Table 4.1).

The estimates varied widely due to a number of factors. First, boundaries of forests are not always well delineated. Along a climatic gradient, density of trees may gradually decrease. For example, a gradient could begin with a forest with a closed canopy that transitions to a savanna with open spaces between trees; the savanna gives way to a grassland or shrubland. Different

Table 4.1. Estimates of the global area of tropical moist forest, and rate of deforestation from the 1970s to 1990. Values for area are in millions of hectares. Rate of deforestation is in millions of hectares per year. (Adapted from Grainger 1993; Pearce and Brown 1994; Achard et al. 2002)

Period

Area of forest

Area deforested/annum

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