Better Trees - justfatlard

A vanilla tree stops dead at the edge of its outermost leaf block, which from any distance reads as a green box with a trunk under it. This replaces those edge leaves with stair-shaped leaves, so a canopy rounds off the way a real one does. It is a small change made in a lot of places at once, and the result is a skyline rather than a stack of cubes.

Two smaller things ride along: some trees grow far larger than they should, and a sapling nobody picks up eventually plants itself.

Leaf Stairs

After any tree finishes generating — from a sapling, from worldgen, or drawn as part of a structure — its outermost edge leaves are swapped for matching leaf stairs. Trees a structure places get the same treatment as ones that grow, so a village orchard does not stand out against the forest behind it.

They are leaves, not decoration. They decay when disconnected from logs, on the scheduled tick the way vanilla leaves do rather than a minute later. They block snow according to their orientation, they cannot be waterlogged, and they are walked on like stairs rather than like a full block.

They are tinted to match their parent. Biome-dependent foliage colour for most species, fixed tints for spruce and birch, untinted for cherry and pale oak. Poplars get stairs too, in all three of their colours.

Leaves Keep To Their Own Wood

Vanilla asks only whether there is a log within six blocks. So a birch beam run through a wall holds a felled oak's crown up in the air, and clearing a tree farm leaves a shell of somebody else's leaves standing in it.

Here a leaf only counts wood of its own species. Fell an oak and its leaves come down, whatever else is nearby; build with any log you like and nothing sticks to it. Leaves do not prop each other up across species either, so an oak canopy touching a birch one keeps its own edges.

Worked out from names, not from a table. A mod shipping walnut_log and walnut_leaves is handled the day it is installed, with no datapack and no entry to add. The few that do not follow the rule - azalea, which grows on oak, and bamboo - are named individually.

Unknown means yes. A block whose name says nothing gets vanilla's own answer. Support is only ever taken away when the neighbour is certainly a different tree, because being wrong in that direction deletes somebody's canopy and being wrong in the other leaves it exactly as it was.

This mod's leaf stairs are covered for free: they are leaves, and their names carry their species the same way vanilla's do.

Ancient Trees

A small chance — 0.5%, during worldgen only — that a tree generates as its larger fancy or mega variant instead of the normal form, for the species that have one. Big enough to be worth walking to, rare enough that finding one is an event.

Worldgen only, deliberately. Saplings used to roll for it too, at about 1%, which quietly made an ancient a crop: plant enough and you get one, and the rarity that made it worth walking to was gone. They are something you come across now, not something you farm. The roll is gated on the tree being placed into a chunk that is still generating rather than into a world that already exists, because a sapling growing runs the very same feature — deleting the sapling path alone would have left the worldgen roll firing for saplings anyway.

An ancient conifer's cone has to clear its own trunk, so the shape holds up rather than growing through itself.

Self-Seeding Saplings

Saplings fall out of trees by the thousand and are picked up by nobody. Left alone they sit as items until they despawn, which is the one thing a seed does not do.

A dropped sapling lying on ground it could grow in gets one chance to take root there, at about 60%, rolled once — not once per tick, because a repeated roll of any size is a certainty given long enough. The ones that fail despawn the way they always did, so a forest floor does not carpet over.

It waits a minute first. Five seconds was the original number and it was not long enough to be either thing: saplings rooted under players walking over to collect them, and a stack set down for a moment was gone. A minute is well short of vanilla's five-minute despawn, so a seed that takes has genuinely been left.

Pandorical

Better Trees registers its leaf stairs through Pandorical — each one standing in for its vanilla leaf block — and applies the per-species tint through it as well. Pandorical is required on both server and client; there is no vanilla-client fallback, because a client with no leaf stairs has nothing to draw.