I'd be more worried about the splinters than if you ever get any more branches out of it.... quit being a damn tree... hugger. perverts... can't do anything on the net without them popping in.
Seriously, short of chopping a tree down, trees randomly regrow their produce. Decay occurs naturally and randomly on the map (see also decaying buildings, tree growth stages, and other related topics). The tree has to be hit by one of these decay ticks to have it's branches and such regrown.
fake edit: damn ninjas... take that two days as the bottom of the average range. I've seen it take significantly longer in a few cases.
Opinions expressed in this statement are the authors alone and in no way reflect on the game development values of the actual developers.