From the patch notes: 2021/10/04 v 0.203.10

Acorn & Birch seed drop rate increased

For birch, the first value for Meadows variant 1 and second value is for Meadows variant 2 and Plains
Birch seeds: Average drop from 0.15/0.1 to 0.5/0.38
Birch resin: Average drop from 0.3/0.2 to 0.25/0.19
Birch feathers: Average drop from 0 to 0.25/0.19
Oak acorn: Average drop from 0.1 to 1.0
Oak resin: Average drop from 0 to 1.25
Oak feathers: Average drop from 0 to 0.5

Which sounds like replacement levels for acorns on average meaning you're likely to roll snake eyes at some point and run out of trees unless you start with hundreds.