Grove v3

The pipeline. A stand of individual trees (the Plant tab — Wilding's model) grows in continuous world metres: each year every stem competes for light, grows its crown, may die, and seeds in. That stand is the single source of truth. To draw a given year, each stem's crown is splatted onto whatever grid the Sheet asks for (page shape × grid resolution), producing per-cell driver values — bare, pioneer, thicket (mid), canopy, cover — with moisture, water and mycelium painted on top as authorable overlays. Each layer maps a signal to a mark family (vector marks or a Material — an image fill you pick or import). One geometry pass emits abstract primitives (dots · segments · paths · masked textures); two backends draw them — Canvas2D for the live scrub, SVG on export — so the plot always matches the screen. Because the stand lives in metres and the grid only samples it, the simulation and the drawing line up at any resolution and a resize re-derives without re-growing.

The algorithms.

• The stand — individual-based succession (Wilding's model) — real stems live at continuous (x, y) in metres, each with a crown radius that grows toward a species ceiling. Each year, within a fixed ~5 m competition bucket the tallest stems shade the shorter (light = e^{−k·crown-above}, Beer's law); growth is scaled by that light raised to (1−shade tolerance), a Gaussian moisture match, and local fertility; stems die from age, suppression, crowding and windthrow; mature stems seed in by dispersal (with mast-year pulses for heavy seeds), and sown species keep a low seed rain, with establishment gated by ground light, moisture, seed mass, and the feedbacks below. Deterministic (seeded mulberry32); Reseed draws a different possible future. Every species parameter is editable in the Plant tab. To draw a year, each crown is splatted as a smooth radial kernel onto the current grid (cover = 1−e^{−β·occupancy}, mass-conserving so it reads the same at any resolution), then split into pioneer / thicket / canopy by the stems' successional roles. v2: seedlings inherit their parent's realized shade/drought/growth traits (regressed toward the species mean by a heritability knob) plus a mutation draw, so under selection each lineage adapts to its microsite over the decades (watch the Evolution strip); establishment also carries a Janzen–Connell conspecific penalty, allelopathy from interfering species, and niche partitioning that eases interspecific crowding. Life-forms beyond trees — shrubs, grasses, wildflowers, ferns — are the same individual-based stems with small crowns and low height, so tall trees overtop them through the ordinary competition; a form tag only changes how each is drawn (a grass tuft, a fern's fronds, a shrub clump) and labelled. Add or delete plants and recolour any of them in the Plant tab. Your whole scene autosaves to this browser and reloads with you (plus named saves). A stylized teaching model over a small, illustrative plant pool — a real selection-plus-inheritance loop, but hand-tuned and not certified ecology.
• The coupled ecosystem (the System tab) — alongside the trees, a stack of cell fields is stepped each year and they act on one another: canopy crowns cast shade (ground light = e^{−shade·crown-density}); light + moisture + fertility set the undergrowth ceiling (so the herb layer thins under canopy and floods the gaps); canopy and undergrowth drop litter, and dying trees leave deadwood (nurse logs); decomposition of that dead matter — faster where it is wet, shaded and colonised — releases fertility back into the soil (the nutrient cycle); mycelium grows on shade × wet × dead-matter, spreads by diffusion, then retains moisture and helps seedlings (mycorrhizal feedback); moisture = soil + water-proximity + canopy/mycelium retention − tree transpiration − drought. Painting the ground now steers the stand (trees grow where it is wet, not on a global dial), and every arrow above is a strength you set in the System tab; the Sheet-tab Overlays read each field's area of influence. Also stylized — grounded feedbacks, illustrative numbers.
• Crowns (per-tree ink) — the default mark, and the tightest tie between the plants and the drawing: every living stem's crown is inked in place — pioneers stippled, thickets single-hatched, canopy cross-hatched — clipped to the crown circle and thickening as it grows. Deterministic per stem (seeded from its fixed world position, so a crown's texture is stable while its radius expands). Because it reads the same stems the fields are splatted from, a cluster of trees makes a cluster of ink — the hatch is the stand. The field marks below (stipple/hatch/cross on the derived bare/pioneer/mid/canopy fields) remain available as looser, cartographic alternatives.
• Materials — a layer can tile a chosen image (the built-in Graphic Textures library, or your own imports kept in a persistent Mine group), keyed so its black marks become ink and its white ground goes transparent, then masked to where its driver is present so it grows in with the years. One primitive per rule; the SVG export embeds the tile as a data-URI <pattern> + a per-cell <mask>, so the plate matches the screen.
• Water distance — a multi-source breadth-first flood-fill (BFS) from painted water cells; near-water ground is wetted by an exponential decay of that distance.
• Stipple / poché — points on a fixed jittered lattice, kept when the driver exceeds each point's stored random threshold (a Poisson-disk-like fill that grows as the driver rises, never re-scatters). Poché uses big overlapping filled disks above a threshold → a solid mass with an organic edge.
• Line hatch & cross-hatch — parallel lines swept across the sheet, each clipped to the canvas (Liang–Barsky) and broken into segments where the driver is present, with per-line angle jitter + a sine wobble so it reads hand-drawn, not like graph paper. Cross-hatch is two passes at ~78°.
• Flicks & crossed dashes — short oriented strokes on the lattice; riparian band = shore-parallel ticks whose direction is the gradient of the water-distance field.
• Mycelium web — the space-colonisation algorithm (Runions et al. 2007): filaments grow from wherever the mycelium field is rich (that field is itself grown by the coupled ecosystem — shaded, damp, dead-matter-rich soil — plus any seed you paint) toward vegetated attractors, branching and thickening with the years.
• Randomness — a seeded mulberry32 PRNG + hash-based value jitter, so every drawing is deterministic and reproducible.

Data sources. None external — this is a designer-authored, stylized model: the site and seed mix are what you set in the Plant tab, the succession is the individual-based model above (illustrative, editable trait values, not cited ecology), and water/soil/mycelium/marks are drawn, not sensed. Nothing here should be read as certified ecology or hydrology.

engine self-tests: …