Trees can generate on non-dirt blocks

The Bug:

Trees can generate on non-dirt blocks.

Here is an example:

Seed: -5497747566889979774
Coordinates: /execute in minecraft:overworld run tp @s 10080.85 63.00 10500.31 -64.61 32.31

Steps to Reproduce:

1. Generate a world with the seed provided above and teleport to the given coordinates.
2. Look closely at the tree and the block it has generated on.
3. Take note as to whether or not trees can generate on non-dirt blocks.

Observed Behavior:

Trees can generate on non-dirt blocks.

Expected Behavior:

Trees would not be able to generate on non-dirt blocks.