Trees in 1.2.10 are generating without trunks. Started noticing far from world spawn (around 8000,-5000).

I deleted the nearby regions from my world, reverted to 1.2.9.1, and the trees started generating correctly again.

Try redownloading 1.2.1.0. There was a version of it that was up for a few hours (I believe) that had this problem, but I quickly deleted it in favour of one that had a few more hotfixes applied.

Closing stale issue.