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.

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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.

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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

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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

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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.

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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+