We've begun building the PvP area Trenchland south of the forest.
http://blacraft.createaforum.com/blacraft-general/possible-future-battleground/msg3567/#msg3567I guess it should be ok, but if you don't need all of the forest, maybe it'd be better to not claim it all, so there's some left for Trenchland.
Also Blotz, you don't need to claim a desert to gather sand from it. You could also set up a portal in a far away desert and gather sand there with donkey and enderchest. Ofc it's easier to do closer to your base but it also leaves an ugly environment, but it's your choice.