Answer:
Lots. Especially birds, and squirels, and those trees can crush on little animals too. Plus without trees, we won't be able to brethe! And with very little trees, animals won't be able to hide from hunters very well. So I'm probably guessing that ALOT of animals will lose their homes if we cut down trees to make our homes. Possibilities are that lots of animals will be extinct if we keep cutting down trees.