Deforestation is the process of clearing forest, and it has been going on as long as humans have been clearing areas in which to cultivate plants. Even tropical deforestation, which is what gets environmentalists excited, has been occurring on a large scale for centuries. However, many people believe that at current rates, tropical deforestation is particularly damaging. They believe that tropical rain forests are disappearing at such a rate that they will vanish within 100 years, eliminating the majority of plant and animal species on the planet. The effects on global climate and biodiversity may well be catastrophic.
Most deforestation is done for agricultural purposes - to clear land for grazing herds, usually cattle, or for planting crops. At its most humble, this involves a farm family chopping down an acre or 2 and burning the wood debris - this is called slash and burn agriculture. Far more damaging is intensive modern agriculture, which happens on a much larger scale, sometimes affecting huge tracts of land. Environmentalists get particularly upset about large scale clearing of land to raise beef for human consumption. Commercial logging, cutting trees for sale as timber or pulp, is another common form of deforestation. This can be selective, with only the economically valuable species being cut, or massive, with all trees clear-cut. Unlike slash and burn agriculture, which relies on human power, modern methods use machinery which are far more intrusive and damaging to the environment.