Heartwood
Befriend a real tree. Every meeting is a ring.
Pick a real tree — by your house, your school, in the park. Photograph it, work out what it is, hug it and mark it on the map. Then keep coming back: the friendship grows only from meetings at the tree itself, and over a year they build up into a sawn cross-section of rings. Free, no ads, no account.
English · Русский · Changelog
The idea
A tree is the most patient friend there is: it stays exactly where you left it, for a hundred years. Heartwood makes a friendship out of that. Nothing in the app moves the friendship forward except walking up to the tree; and what you get back is a record of the time you spent together, the way a tree keeps its own — in rings.
How it works
- Meeting a tree. Photograph it whole: the photo becomes an ink engraving, its portrait. Work out the species with an illustrated key (leaf, bark, needles), like an old field guide — twelve species, from oak and birch to rowan and poplar. Hug the trunk: did your hands meet? Otherwise give the girth, and the forester's rule (diameter × the species' growth factor) tells you roughly how old it is — "about 190 years: seven generations of people". Name it, write one line on why this one, and set its point on the map.
- The cross-section. Every day you meet is a ring; the pith is the first meeting. A ring is drawn in the season's colour, a hug warms the wood, a long absence leaves a dark line, like a dry year. Tap a ring and the tree remembers that day in its own voice: "It was snowing. One line of footprints led to my trunk."
- Only at the tree. Everything happens within 50 metres of its point (GPS):
- Hug — the phone screen-in against your chest, your chest against the trunk. While the proximity sensor is covered and the phone is still, a heartbeat plays in your hand and slows from yours toward the tree's. A minute of it is a hug.
- Listen — the microphone against the bark for ten seconds: the voice of the day, to play back in winter.
- Bark rubbing — photograph the bark, then rub it out of blank paper with a finger, like graphite. The relief comes from the real ridges of this tree.
- A leaf to press — one fallen leaf a season goes into the herbarium.
- A photo over the last — fit each new photo over a ghost of the previous one, and the chronicle becomes a timelapse of the tree through the years.
- Sit beside it — the phone face down; a clock that only runs while it lies still. Nothing else happens.
- The hollow — a note to yourself that opens a year later, only at this tree.
- Friendship. Stranger, acquaintance, pal, friend, kindred: by meetings, by seasons met in, and kindred only after a full year.
- The grove. Up to seven trees on an old-survey-style map. Switch to underground and the mycelium shows between them, with news running along the threads from the friend you met last — "“Old Man” passes on through the roots: the jays are hiding his acorns again."
- Calls, rarely. A tree calls when it has a reason: the linden is in blossom, the maple is all red, the first snow, a year since you met, a note ripe in the hollow. Twice a month at most, never at night.
- No guilt. A tree doesn't wilt if you vanish. Moss grows on its card, and when you come back it says "I knew you'd come."
- Pass a tree on. A QR code a friend reads with their phone camera: the tree becomes theirs too, with their own rings.
Download
Get it on Google Play.
Or get Heartwood.apk from the latest release and open it on your phone (allow installing from your browser or file manager when asked). Android 9 or newer.
Privacy
No ads, no accounts, no analytics. Everything stays on the phone. The only network requests are OpenStreetMap tiles and the current weather at the tree's rounded coordinates (Open-Meteo, falling back to MET Norway) — so a ring can remember the rain. Photos are taken with the phone's own camera app; the app has no camera permission.
Build
./gradlew assembleDebug # app.heartwood.dev
./gradlew assembleDebug -Pdemo # app.heartwood.demo: a lived-in grove in Prague
./gradlew testDebugUnitTest # rules: rings, friendship, calls, gifts
./gradlew testDebugUnitTest -Prender # screen renders + species sheet to app/build/art
python tools/shots.py # renders → docs/screenshots
Kotlin, Jetpack Compose, Room, osmdroid. Every tree, leaf, bark rubbing and cross-section is drawn in code.
License
MIT. Map data © OpenStreetMap contributors. Part of Stillcraft.
