LeafTreeGen

Procedural, biome-aware custom trees that generate through vanilla worldgen.

LeafTreeGen adds dozens of custom tree species. Trees are mathematically defined in JSON and baked into vanilla .nbt structure templates at startup, then added to jigsaw template pools so the game's own worldgen handles placement. No runtime block-placement listeners.

Made as a cross-platform utility based on the Python code I originally wrote for my personal Iris world using .iob files. Iris now adopts my procedural engine in its latest builds.

I've reworked it so you can optionally run it once for datapack (.nbt-based) generation, or keep it around for its ability to manage procedural generation and custom saplings.

---

Screenshots

Cherry Grove Giant - a towering cherry-blossom giant anchors its matching biome above a grove of smaller cherry trees.

Dark forest canopy - dense overlapping high canopies with scattered giant mushrooms, viewed from above the treeline.

Dark Forest Mushroom.

Custom savanna trees.

Christmas Tree - all trees are placeable via NBT-tagged saplings.

---

Features

• Biome-matched species - savanna acacias, dark-forest canopies, glacier pines, cherry groves, spiral-crown forests, and rainbow groves, mapped to the biomes they suit
• Procedural engine - trees are built in Java from per-species parameters: height, trunk shape, lean angle, and canopy layers
• Jigsaw worldgen - the plugin writes a vanilla worldgen datapack on first load and lets Minecraft's structure system place the trees
• Plantable saplings - /leaftree give hands out NBT-tagged saplings that grow into a random variant when planted in a valid biome
• Reload command - /leaftree reload rebakes all variants and regenerates the datapack
• Server-friendly placement - large trees are placed across multiple ticks under a per-tick budget to keep the main thread responsive
• Multi-platform - one jar runs on Paper, Folia, Fabric, and NeoForge with the same features (worldgen, saplings, and the /leaftree command) everywhere

---

Species Highlights

Category	Examples
Temperate	Forest, Birch Forest, Old-Growth Birch, Maple-Birch Giants, Ashwood
Tropical	Jungle, Cherry Grove, Jacaranda Grove
Cold	Taiga, Old-Growth Pine Taiga, Glacier Pine
Dark & Exotic	Dark Forest Giants, Spiral-Crown Forest, Rainbow Grove, Glowcap

Full biome tree map | Biome | Species | Iconic shape | Role | |---|---|---|---| | `forest` | `forest` | Rounded oak, mid to large | Primary | | `flower_forest` | `oak-small-mid` | Small-to-mid rounded oak, sporadic | Primary | | `plains` | `oak-small-mid` | Sparse small-to-mid oak | Primary | | `meadow` | `oak-small-mid` | Sparse small-to-mid oak | Primary | | `meadow` | `meadow-azalea` | Small oak trunk with azalea crown | Sprinkled accent | | `meadow` | `rainbow-grove` | Birch trunk with multi-hue canopy | Rare landmark | | `dark_forest` | `glowcap` | Lit brown-mushroom shrub | Understory | | `dark_forest` | `dark-forest-floor-lights` | Tiny shroomlight glow shrooms | Floor litter | | `dark_forest` | `dark-forest-mids` | Small-to-medium twisted dark oak | Midstory | | `dark_forest` | `dark-forest-megas` | Titan dark oak with massive canopy | Canopy | | `birch_forest` | `birch-forest` | Tall slender white birch | Primary | | `old_growth_birch_forest` | `old-growth-birch-forest` | Towering old-growth birch | Primary | | `old_growth_birch_forest` | `maple-birch-giants` | Giant maple-and-birch landmark | Rare landmark | | `taiga` | `taiga` | Conical spruce | Primary | | `snowy_taiga` | `evergreen` | Snow-dusted conical spruce | Primary | | `snowy_taiga` | `christmas-tree` | Festive decorated spruce with ornaments | Very rare landmark | | `old_growth_pine_taiga` | `old-growth-pine-taiga` | Tall bare-trunked pine | Primary | | `old_growth_spruce_taiga` | `old-growth-pine-taiga` | Tall bare-trunked pine | Primary | | `snowy_plains` | `glacierpine` | Frost-laden spruce with icicle tips | Primary | | `ice_spikes` | `glacierpine` | Frost-laden spruce with icicle tips | Primary | | `grove` | `glacierpine` | Frost-laden spruce with icicle tips | Primary | | `snowy_slopes` | `glacierpine` | Frost-laden spruce with icicle tips | Sparse | | `frozen_peaks` | `glacierpine` | Frost-laden spruce with icicle tips | Sparse | | `jagged_peaks` | `glacierpine` | Frost-laden spruce with icicle tips | Sparse | | `jungle` | `jungle` | Jungle trees, small to giant | Primary | | `sparse_jungle` | `jungle` | Jungle trees, small to giant | Primary | | `bamboo_jungle` | `bamboo-jungle` | Jungle trees ringed by bamboo | Primary | | `savanna` | `savanna` | Flat-topped leaning acacia | Primary | | `savanna_plateau` | `savanna` | Flat-topped leaning acacia | Primary | | `windswept_savanna` | `savanna` | Flat-topped leaning acacia | Primary | | `cherry_grove` | `cherry-grove` | Layered pink blossom crown | Primary | | `cherry_grove` | `jacaranda-grove` | Giant weeping cherry-wood jacaranda | Rare landmark | | `windswept_hills` | `ashwood` | Gaunt gray dead pale-oak with cobwebs | Primary | | `windswept_forest` | `ashwood` | Gaunt gray dead pale-oak with cobwebs | Primary | | `windswept_gravelly_hills` | `ashwood` | Gaunt gray dead pale-oak with cobwebs | Primary | | `swamp` | `swamp` | Vine-draped weeping oak + mangrove | Primary | | `mangrove_swamp` | `swamp` | Vine-draped weeping oak + mangrove | Primary |

---

Commands

Command	Description
/leaftree generate species=<id>	Place a tree at your cursor (admin test)
/leaftree give species=<id> [player] [amount]	Hand out custom saplings
/leaftree list [species=<id>]	List registered species or variants
/leaftree reload	Apply config changes and regenerate the datapack

Requires the leaftreegen.admin permission node.

---

Configuration

Species are defined as JSON files in the species/ folder. Biome assignments and placement tuning (spacing, separation, salt) live in config.yml, with per-species overrides.

generation-mode: DATAPACK   # DATAPACK | PROCEDURAL | BOTH | NONE

placement:
  glacierpine:
    spacing: 6
    separation: 3
    biomes:
      - minecraft:snowy_taiga
      - minecraft:grove

{
  "name": "glacierpine",
  "procedural": {
    "trunk-block": "minecraft:spruce_log",
    "leaf-block": "minecraft:spruce_leaves",
    "height-min": 10,
    "height-max": 18,
    "trunk-shape": "LINEAR",
    "canopy": [
      { "yOffset": 0, "radius": 4 },
      { "yOffset": 3, "radius": 3 },
      { "yOffset": 6, "radius": 2 }
    ]
  }
}

Requirements

• Java 25+
• One of:
• Paper or Folia 1.21+
• Fabric 26.1+ (Fabric Loader 0.18.4+, Fabric API)
• NeoForge 26.1+