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+

leaf-treegen