Summary:
I noticed that trees (dark oak specifically, might affect others) can generate on the wrong blocks, such as sand or clay. It appears this happens most often when they are beside water.

Steps to Reproduce:
1. Use the world seed -655594102
2. /tp to coordinates: 375 64 146
3. Look for the Dark Oak Tree standing on sand

Observed Results:
The trees are growing on the wrong blocks such as sand.

Expected Results:
Trees should only generate on dirt or grass.

Screenshots/Videos attached: Yes

Notes:

• Another example, seed: -913365131 Coordinates: -6075 62 -23810
• Confirmed to affect other trees as well, I've observed Birch and Oak trees on sand and gravel.