We must save our environment for the future because if we plant a tree now, after 5-10 years only it will grow into a big firm tree. If trees are not there in future it is difficult for humans to live because tree are the ones who turns carbon dioxide into oxygen for us to breath. It even gives us food, wood, rubber, etc. It is our duty to take care of our environment. Environment has done a lots of thing for humans but humans in return have not done anything for it.
Hope that might help you........^_^