With only the below mods active;

Optifine 1.0.0 (shutting Optifine off has no effect)
Biomes O Plenty 1.18.2-16.0.0.109
Terrablender 1.2.0.126
DT 1.18.2-0.11.0-Beta10.1
DT+ 1.18.2-0.2.0-Beta4
DT:BOP 1.18.2-3.0.0-Beta3

Specific biomes do not generate any trees - namely:

• Maple Woods: full MultiMC console feed from launch to exit
• Snowy Maple Woods: full MultiMC console feed from launch to exit
• Boreal Forest: full MultiMC console feed from launch to exit

BOP biomes which do generate trees seem to only do so upon initial world creation - generation quits when exiting the game and returning to that world (see screenshot 2). The issue seem to be DT:BOP, as vanilla style trees resume generating if DT:BOP is removed. Tested with all three beta versions for 1.18.2

To Reproduce
Create a new world in single biome mode in Boreal Forest, Maple Woods, or Snowy Maple Woods BOP biomes, no trees will generate. OR, create a new world in single biome mode in Old Growth Pine Taiga, fly around a bit to bring up some chunks, save/exit, close game and restart, return to that world and all other than blossom trees will stop generating in new chunks.

Screenshots

Journeymap showing clear border where tree generation stopped after leaving and returning to this world:

Rendering Glitches
This happens with or without optifine and with/without shaders active, no rendering or graphical issues present

Crashes
This does not cause any game crashes and does not seem to affect anything beyond tree generation - all trees including those from bugged biomes can be planted manually and will grow without issues

Mods List
Full list is in the console logs - only the below were active in MultiMC while testing:

• Optifine
• Dynamic Trees
• Dynamic Trees Plus
• Dynamic Trees BOP
• Terrablender
• BOP

Found the source of the trees missing from some BOP biomes:

Some biomes are missing a generation code block or are named incorrectly in (mod jar)\trees\dtbop\world_gen\default.json

Ex. snowy_maple_forest should be snowy_maple_woods, changing forest to woods in the json fixed tree generation in that biome.

Regular maple woods had no generator code, so tried duplicating the block for the snowy variant and changing the biome name to maple_woods, that fixed missing trees in that biome. There are others in the same boat but I didn't go thru all the current biomes in BOP

Also narrowed down the stopped generating after world reload issue to vanilla biomes only, doesn't seem to happen to BOP biomes. There's a post specifically for this at #93 , as this one was originally under the regular DT mod