is a method of farming where trees are burned off and crops are planted until the soil become infertile.

Slash and Burn Farming, sorry I don't know if there is a specific word for it.

Explanation:

roosevelt believed that in light of the country's recent military successes, it was unnecessary to use force to achieve foreign policy goals, so long as the military could threaten force. this belief, and his strategy of “speaking softly and carrying a big stick,” shaped much of roosevelt's foreign policy.