One of the laws of war recorded in this Torah portion is the prohibition against chopping down fruit trees even in the course of laying siege to a city. The Sages describe the extent to which chopping down a fruit tree has an effect on the world.

At the moment that one chops down a fruit-bearing tree, a sound emanates from one end of the world to the other, but the sound is unheard by people. (Pirkei deRabbi Eliezer [Higer] 33)