You have to create a brand new world to see the result. Navezgane works fine, just start a new game name each time you want to test it. SOme objects have a large deco radius and might not allow a tree to spawn near it, but very few, usually its trees that have that property.
i created ewith every test a new world and i tested it again today. i deleted all decorations from main-biome and in sub-biomes(except oaktrees). no tree is spawning.when im changing treeblock to another block(for example concrete-pillar), these blocks get spawned.(i tried with diffent blocks). i can show you an example ( i shortened it because of the survey with only one sub-biome).
<biome name="pine_forest" topsoil_block="terrForestGround" biomemapcolor="#004000">
<weather>
<Temperature min="-35" max="15" prob="1"/>
<!--<Fog min="0" max="0" prob=".9"/>-->
<!--<Fog min="100" max="100" prob=".1"/>-->
<CloudThickness min="0" max="0" prob=".3"/>
<CloudThickness min="10" max="70" prob=".6"/>
<CloudThickness min="100" max="100" prob=".1"/>
<Precipitation min="0" max="0" prob=".0"/>
<Precipitation min="50" max="100" prob=".75"/>
<Wind min="10" max="20" prob="0.9"/>
<Wind min="20" max="100" prob="0.1"/>
</weather>
<subbiome prob="0.4551"> <!-- Ore Sub Biome: * leadOre -->
<layers>
<layer depth="1" blockname="terrForestGround"/>
<layer depth="3" blockname="terrDirt"/>
<layer depth="1" blockname="terrStone">
<resource blockname="terrGravel" prob="0.7830" rwgGenerationType="all"/>
</layer>
<layer depth="*" blockname="terrStone">
<resource blockname="terrOreLead" prob="0.6500" rwgGenerationType="all"/>
<resource blockname="terrGravel" prob="0.7830" rwgGenerationType="all"/>
</layer>
<layer depth="1" blockname="terrStone"/>
<layer depth="3" blockname="terrBedrock"/>
</layers>
<decorations>
<decoration type="block" blockname="treeOakLrg01" prob="0.1" rotatemax="7"/>
<decoration type="block" blockname="treeOakMed01" prob="0.1" rotatemax="7"/>
<decoration type="block" blockname="treeOakMed02" prob="0.1" rotatemax="7"/>
<decoration type="block" blockname="treeOakSml01" prob="0.1" rotatemax="7"/>
</decorations>
</subbiome>
<!-- Block layers: Pine Forest, Local ore: leadOre -->
<layers>
<layer depth="1" blockname="terrForestGround"/>
<layer depth="3" blockname="terrDirt"/>
<layer depth="*" blockname="terrStone">
<resource blockname="terrOreIron" prob="0.6500" rwgGenerationType="all"/>
<resource blockname="terrGravel" prob="0.7830" rwgGenerationType="all"/>
<resource blockname="terrOreSilver" prob="0.00030" rwgGenerationType="all"/>
<resource blockname="terrOreGold" prob="0.00020" rwgGenerationType="all"/>
<resource blockname="terrOreDiamond" prob="0.00010" rwgGenerationType="all"/>
</layer>
<layer depth="1" blockname="terrStone">
<resource blockname="terrGravel" prob="0.7830" rwgGenerationType="all"/>
</layer>
<layer depth="10" blockname="terrStone">
<resource blockname="terrOreLead" prob="0.6500" rwgGenerationType="all"/>
<resource blockname="terrGravel" prob="0.7830" rwgGenerationType="all"/>
<resource blockname="terrOreSilver" prob="0.00030" rwgGenerationType="all"/>
<resource blockname="terrOreGold" prob="0.00020" rwgGenerationType="all"/>
<resource blockname="terrOreDiamond" prob="0.00010" rwgGenerationType="all"/>
</layer>
<layer depth="1" blockname="terrStone"/>
<layer depth="3" blockname="terrBedrock"/>
</layers>
<!-- Decorations Main: Pine Forest -->
<terrain class="Mountains"/>
</biome>
did i something wrong??? i know i did something wrong but why other blocks get spawned and not trees. im trying to do a sub-biome with only birches. i like that birches and want a birchforest over a nitrate-subbiome.
greetings and thx for spending your time