Here, basically every second tree is a rubberwood one. Game version: 1.19.2 (Other worldgen mods: BOP + Terralith)

Biome: Swamp (it has custom trees because of Terralith)

@Wanderer70 ok checked it, thought about it, tested a bit.
Yes that's intended.

Not really a bug.
While the amount of IC2C trees is higher because it's trees most likely get a bit more priority, the rubber trees in swamps are ment to be plentiful so that a swamp is a likely target to get ic2c started.

Not closing this yet because I will do a few tests with it.

Aaah, okay! I didn't know that