Slash and burn agriculture is a method where forests are cleared by cutting down vegetation and burning remaining material. This provides nutrients to the soil from ash to fertilize crops for a few years, until the land is degraded and farmers must clear new plots. While sustainable at low population densities, frequent slash and burn can ultimately destroy forests when human populations increase and demand for land grows.

1. Shifting Cultivation
(Slash and Burn Agriculture)
• Slash and burn agriculture is a shifting cultivation method of
growing food in which wild or forested land is clear cut and any
remaining vegetation burned.
• The resulting layer of ash provides the newly-cleared land with
a nutrient-rich layer to help fertilize crops.
• However, under this method, land is only fertile for a couple of
years before the nutrients are used up. Farmers must abandon
the land, now degraded, and move to a new plot—clearing
more forest in order to do so.
• In Bangladesh and India, the practice is known as jhum or jhoom.

2. Purpose of Slash and Burn
• Slash-and-burn causes temporary deforestation. Ashes from the
burnt trees help farmers by providing nutrients for the soil.
• In low density of human population this approach is very sustainable,
but the technique is not scalable for large human populations.
• Slash-and-burn farmers typically plant a variety of crops, instead of a
monoculture, and contribute to a higher biodiversity due to creating
mosaic habitats. The general ecosystem is not harmed in traditional
slash-and-burn, aside from a small temporary patch.

3. Slash and Burn in India

4. Effects of Slash and Burn
• When slash-and-burn is practiced in the same area too often, because
the human population density has increased to an unsustainable
level, the forest will eventually be destroyed.
• Modern slash-and-burn techniques are a significant source of carbon
dioxide emissions, especially when used to initiate permanent
deforestation.
• Slash and burn agriculture also results in significant soil erosion and
accompanying landslides, water contamination, and/or dust clouds,
as without trees and vegetation and their root systems, soil washes
away during heavy rains and blows away during droughts.