{
  "feature": "minecraft:mangrove_worldgen",
  "placement": [
    {
      "type": "minecraft:block_predicate_filter",
      "predicate": {
        "type": "minecraft:would_survive",
        "state": {
          "Name": "minecraft:mangrove_propagule",
          "Properties": {
            "age": "0",
            "hanging": "false",
            "stage": "0",
            "waterlogged": "false"
          }
        }
      }
    }
  ]
}