{
  "type": "minecraft:rule_based",
  "rules": [
    {
      "if_true": {
        "type": "minecraft:not",
        "predicate": {
          "type": "minecraft:matching_block_tag",
          "tag": "minecraft:cannot_replace_below_tree_trunk"
        }
      },
      "then": {
        "id": "minecraft:dirt"
      }
    }
  ]
}