A young tree should be more effected and hurt by the winters then
A tree which has survived many, and is very strong. perhaps the effects
of winter could withdraw based upon how many you have lived through-

lived through 10 winters: you loose random damage durring winter
lived through 20 winters: you are more precise on your casting rounds
lived through 30 winters: your heart is more resistant to the cold
lived through 40 winters: your never miss a spell round
lived through 50 winters: you are hardy, and fare winter well.

the #'s I used (the amount of winters) is ONLY AN EXAMPLE these are
not realistic obviously, but just to show the gradual flow into a
strong Ent. There can even be a new line in every ents Desc, describing
their bark (how thick, Gnarled, color) to show how far along they are.

I think this is good because it will still stop people from reincing
but will work hand in hand with the Ents long lifespan, to provide players
who simply love to play the race a bonus if they stat in it.
(and for all you assholes, I meant reinc into habo'ers)