手册:Minecraft:tree feature/常规树干语法

"trunk": {
  "trunk_height": <par1>,
  "height_modifier": <par2>,
  "can_be_submerged": {
    "max_depth": <par3>
  },
  "can_be_submerged": <par4>,
  "trunk_block": <par5>,
  "trunk_decoration": {
    "decoration_chance": <par6>,
    "decoration_block": <par7>,
    "num_steps": <par8>,
    "step_direction": "<par9>"
  }
}