i suppose you could let your tamed war dragon loose on the trees, but you better be shure to get that dragon out of the burning forest fast, or it will die due to falling trees... and yeah, one dragon did that... got on a rampage, got out of the fort after fleeing dwarfs and spit fire everywhere (well its a dragon^^) setting ablaze the whole forest above my fortress... and killed itself while at it due to a massive tree collapsing onto named dragon, so always fight dragons in forests, they will sooner or later kill themselve (obviously you have to sacrifice one or two dwarfes or perhaps a crapload of wardogs^^ to distract it long enough while the trees burn... also incoming iFUN! through elves if they are still a challenge to your dwarfes^^
EDIT: @ topic: build myself a little greenhouse and trained my roc to *trained* state, after a while of thought about what freaking plant i grow in this greenhouse i came to strawberries and blueberries, strawberrys because i personally like to eat em, and blueberries because i hate them for their taste
oh and some meager goblin army of 60 being completely annihilated by 20 dwarfs clad in steel with steel picks and without a single injury on my dwarfes too, quite unexpected^^ i hope they get some steel or silver weapons next time
EDIT 2: got my dragon to *trained* too, and mutilated that damn goblins again (still only with copper an one with an iron helm...) got some elven warning due to cutting down the whole map and expanded my greenhouse with cranberrys and blackberrys