Sustainable forestry is when new trees are planted to replace ones that have been deliberately cut down and removed. Deforestation is the removal of trees from their natural habitat and it happens where unsustainable forestry or deliberate clearance of trees to provide a change of land use is taking place. In this GCSE Biology quiz we look at its causes and also its effects.
Deforestation takes place all around the world but is often most associated with tropical rainforests since that is where clearance of forest is happening at a great rate at the present time. Some of this clearance involves slash and burn farming techniques. This is where the trees are chopped down and then burnt, leading to the release of large quantities of carbon dioxide and smoke into the atmosphere. The ash from the burnt trees and vegetation fertilises the ground for a while but after a few years, the soil becomes too poor to support agriculture and so a new area is slashed and burnt.
The biggest problems are when deforestation occurs on an industrial scale. Large areas of rainforest are lost each year to mining, and exotic timbers, like teak and mahogany, are deliberately and illegally felled for furniture making and building. Deforestation is also used to provide land to grow crops for making biofuels and to provide cattle and rice fields for food production.
8,000 years ago, much of Western Europe, including the British Isles, was heavily forested. These forests contained many food chains and food webs and some of the top predators included wolves and bears. Although there are still a lot of trees around, the area covered by forests is a tiny fraction of what it was before humans started to clear the forests in order to grow their crops and build their settlements.
But what are the problems associated with deforestation?
Removal of trees contributes to global warming by removing the chance for carbon dioxide uptake by those trees, so less carbon dioxide is removed from the air. It reduces biodiversity and exposes the soils to erosion creating barren land, flooding, mudslides and landslides. Deforestation can nowadays only be prevented by political means in the countries involved, but the economic loss to those countries is a major issue.