You'd be surprised how quickly trees can be removed with a good sized excavator ! They can make short work of a lot of trees in no time flat .
I know they can pop them out like picking up brass. PLEASE correct me if I'm wrong, but I thought that popping out the tree was the easy part of the battle. The hard part was removing roots, and sealing the area with clay after removing roots.
You can fit what I know about building a pond in a thimble, so seriously correct me.