Forest and taiga type biomes spawn with large treeless areas when ore vein spawn sizes are set to excessive values

Roofed forest and jungle biomes are, however, unaffected.

Can't reproduce

Thank you for your report!
However, this issue is Incomplete.

Your report does not contain enough information. As such, we're unable to understand or reproduce the problem.

Please provide the exact preset used to generate the world.

Quick Links:
📓 Issue Guidelines – 💬 Community Support – 📧 Customer Support – 📖 Game Wiki

@violine1101
The exact preset I used is:
{"coordinateScale":171.103,"heightScale":684.412,"lowerLimitScale":512.0,"upperLimitScale":512.0,"depthNoiseScaleX":200.0,"depthNoiseScaleZ":200.0,"depthNoiseScaleExponent":0.5,"mainNoiseScaleX":80.0,"mainNoiseScaleY":480.0,"mainNoiseScaleZ":80.0,"baseSize":8.0,"stretchY":12.0,"biomeDepthWeight":0.0,"biomeDepthOffset":0.0,"biomeScaleWeight":0.0,"biomeScaleOffset":1.0,"seaLevel":79,"useCaves":true,"useDungeons":true,"dungeonChance":21,"useStrongholds":true,"useVillages":true,"useMineShafts":true,"useTemples":true,"useMonuments":true,"useMansions":true,"useRavines":true,"useWaterLakes":true,"waterLakeChance":4,"useLavaLakes":true,"lavaLakeChance":80,"useLavaOceans":false,"fixedBiome":-1,"biomeSize":6,"riverSize":30,"dirtSize":33,"dirtCount":0,"dirtMinHeight":0,"dirtMaxHeight":256,"gravelSize":33,"gravelCount":0,"gravelMinHeight":0,"gravelMaxHeight":256,"graniteSize":50,"graniteCount":2,"graniteMinHeight":0,"graniteMaxHeight":32,"dioriteSize":125,"dioriteCount":1,"dioriteMinHeight":32,"dioriteMaxHeight":96,"andesiteSize":50,"andesiteCount":4,"andesiteMinHeight":96,"andesiteMaxHeight":192,"coalSize":17,"coalCount":20,"coalMinHeight":48,"coalMaxHeight":192,"ironSize":9,"ironCount":20,"ironMinHeight":41,"ironMaxHeight":96,"goldSize":9,"goldCount":2,"goldMinHeight":41,"goldMaxHeight":48,"redstoneSize":8,"redstoneCount":8,"redstoneMinHeight":0,"redstoneMaxHeight":25,"diamondSize":8,"diamondCount":1,"diamondMinHeight":0,"diamondMaxHeight":16,"lapisSize":7,"lapisCount":1,"lapisCenterHeight":25,"lapisSpread":16}.

The diorite_size_125 picture is with this preset and diorite_size_50 is this exact same preset but with diorite size set to 50.

Confirmed. Also, not only trees are missing, all decorations in general aren't generated if there's a huge diorite vein directly below. For example, in deserts there are no cacti.

It's interesting that sunflower plains, roofed forest, and jungle biomes are unaffected then.

Haven't tested in flower forest, mega taiga, or extreme hills + either.