Scorched earth

Scorched earth is a military strategy which involves destroying anything that might be useful to the enemy and withdrawing from an area. The name refers to the practice of burning crops to deny the enemy food sources. The practice may be carried out by an army in enemy territory, or by an army in its own home territory, as in World War II Soviet/Nazi example.

Wars which have involved a scorched earth policy

The Napoleonic Wars in Russia
The British used scorched earth techniques against the Afrikaners during the Boer Wars.
During the American Civil War, General Sherman burned and plundered the countryside on his way to Atlanta.
During World War II, the Soviets employed a highly effective scorched earth policy to counter the Nazi invasion.
The Nazis used a scorched earth strategy against the Finns during the Lapland War, part of World War II.