{
  "format_version": "1.13.0",
  "minecraft:feature_rules": {
    "description": {
      "identifier": "wiki:custom_tree_feature_rule",
      "places_feature": "wiki:custom_tree_feature"
    },
    "conditions": {
      "placement_pass": "surface_pass",
      "minecraft:biome_filter": [
        {
          "test": "has_biome_tag",
          "operator": "==",
          "value": "plains"
        }
      ]
    },
    "distribution": {
      "iterations": 1,
      "x": {
        "distribution": "uniform",
        "extent": [0, 16]
      },
      "y": "q.heightmap(variable.worldx, variable.worldz)",
      "z": {
        "distribution": "uniform",
        "extent": [0, 16]
      }
    }
  }
}