If the wind blows a tree over and the tree lands on an ant, the ant will die. This is not right or wrong. This is of no-thing. And so if you cause the tree to fall, not concieving either yourself, the tree, or the ant, life or death, you are like the wind. This is not right or wrong. This is of no-thing.

But if you push the tree over, concieving of yourself first and knowing that ant will die, you have murdered the ant. If you know you are causing suffering, then don't. It's very simple.