Only in that its started the process, and when left to its own devices will become an oak tree.

Right, but that was not the question. The question was whether it should be considered a tree as is.

Granted, I think no less of someone digging up a sprouted acorn than I do of someone who chops down an oak tree

Seems a bit of a psycho thing to do, yes. But supposing someone had a good reason for it, I'd rather have that than chopping down an oak tree.

In the mean time, we apply transitory boundaries to something we don't even philosophically understand; that being existence.

Supposing that we do not understand it, how reasonable is it to draw one extreme line rather than another?

How transitory? If a man kills a pregnant woman, he will be charged with double murder.

Anti-abortionists were very clever to pass such laws, because that enables this sort of 'logic'. But the act itself would be no better or worse if such laws did not exist.