Source : A-Treefarm _______________________________________________________________________________________________________________ Also at other tree farms.
All treefarms (excluding) d-treefarm don't work because it was either have trees droping apples at the normal rate or collin adds them to the shop and more people wanted them added to the shop but now they all moan.
You can report this to [email protected] and he will either fix it or forward it to the server owner. Make sure to give as much detail as possible, when it started happening (it doesn't matter if you don't know when), and maybe a few screenshots. All in all it should be fixed soon.