I think it was in response to the mass wicker-basketting and bucketing of yore, and the subsequent deforestation, when jorbtar introduced tree regrowth to compete with grass growing. Only it was bugged and resulted in lots of stunted shrubs due to the tree growth/proximity rule, and so it was removed.
Perhaps for the rewrite, trees could coppice from stumps. It's what was done historically, to manage woodland. Chop down a tree, wait 25 years, and there's a new tree where the old one was, no replanting required. Firs don't coppice though, they do need replanting.