Don't count on better tree assets in JNPG and CF2 - PP have basically outsourced all their tree requirements to Speedtree.
You do with your time and your money whatever you want, schmidt61059, but clubcaptain has a point: One single tree will definitely NOT make a difference. You need at least 4 different kinds of trees and 3 different kinds of bushes (bushes are even more of a problem than trees) to create a satisfactory vegetation (a minimal one, the more the better anyway). And not only that, you would need to take them into the modeller software to create a few different models of each version, to avoid getting a very repetitive "Clone Army" look.
I hate to pile it on, but the harsh truth is that the tree situation around here is very dire*), with no help in sight. As for doing a course just for yourself, again, that is your prerogative, but do not sell yourself short before you've got something to show. Once you've finished your private little course, you might as well invite others onto it. Believe me: If you build it, they will come.
*) Addendum: And that is not PP's fault, btw. Nothing they can do about the pervasive specialisation and commercialisation in IT. They lack resources as it is and the internet is not free anymore, good things cost money, can't be helped.