Hey guys so I was generating some trees on my biome and it was working pretty well, but now that I added bedrock ceiling it stopped generating the trees.

Flowers and grass still work perfect tho.

My biome class:

Spoiler

public class CustomPlainsBiome extends Biome {

    public CustomPlainsBiome(Biome.Builder biomeBuilder) {
        super(biomeBuilder);
		
      	// This trees stopped spawning with bedrock ceiling
        this.addFeature(GenerationStage.Decoration.VEGETAL_DECORATION, Feature.RANDOM_SELECTOR.withConfiguration(new MultipleRandomFeatureConfig(ImmutableList.of(Feature.FANCY_TREE.withConfiguration(CustomBiomeFeatures.PURPLE_TREE_BIG_CONFIG).withChance(0.1F)), Feature.FANCY_TREE.withConfiguration(CustomBiomeFeatures.PURPLE_TREE_CONFIG))).withPlacement(Placement.COUNT_EXTRA_HEIGHTMAP.configure(new AtSurfaceWithExtraConfig(1, 0.01F, 1))));
        
        // This Features still work with bedrock ceiling
        this.addFeature(GenerationStage.Decoration.VEGETAL_DECORATION, Feature.FLOWER.withConfiguration(DefaultBiomeFeatures.FOREST_FLOWER_CONFIG).withPlacement(Placement.COUNT_HEIGHTMAP_32.configure(new FrequencyConfig(100))));
        this.addFeature(GenerationStage.Decoration.VEGETAL_DECORATION, Feature.RANDOM_PATCH.withConfiguration(DefaultBiomeFeatures.GRASS_CONFIG).withPlacement(Placement.COUNT_HEIGHTMAP_DOUBLE.configure(new FrequencyConfig(1))));
    }
}

 

And I also tried with the same placement as Flowers but it didn't work

I have a feeling that when tree features generate they have to be able to see the sky but I'm not 100% sure because I haven't tried to do this sort of thing and most of the fields inside of the tree class are obfuscated.