Sometimes Pale Garden Biomes are generated on too small of an area or too rough terrain so that they don't contain a single pale oak tree.

Example Seed: 6002563379176398628
Teleport Command: /tp @s 70723 103 -2081
In this case it generated only on a steep cliff side with a Dark Oak Forest below & a Birch Forest up top.

This bug relates to MC-236649.