{
  "version": 1,
  "schema": "alto-tree-ids/1",
  "release": "20261013-v6.1",
  "generated_utc": "2026-10-12T13:00:00.288411+00:00",
  "bucket_algorithm": "fnv1a_utf8_mod65536_hex4_split2",
  "bucket_note": "FNV-1a (32-bit, UTF-8 bytes) of the key, mod 65536, four hex digits as {hh}/{hh}.json.gz; the tree_details layout.",
  "keys": "tree numbers (canonical: upper case, no hyphen), akl_tree_* record IDs, v4 and v5 crown keys as published",
  "row": [
    "canonical",
    "detail",
    "status",
    "successor",
    "note",
    "extra"
  ],
  "row_note": "canonical = the tree number the key resolves to (null for a number itself, a split or a tombstone); detail = the tree_id whose full record shows that tree (null: the key itself); trailing nulls are omitted.",
  "statuses": {
    "current": "the key is the tree, its marker record or its crown",
    "member": "a record on the tree's crown without a marker of its own",
    "merged": "merged into the tree named by successor (a reviewer correction)",
    "split": "divided between the trees in successor (largest share first)",
    "retired": "no tree carries it now; successor names the tree that replaced it, if any; extra.p is the last known position"
  },
  "notes": {
    "v4_continues": "v4 crown continuing as this crown (at least half of it lies in this crown and no other crown holds a fifth)",
    "v4_split": "v4 crown divided between several current crowns (each holds at least a fifth of it; largest share first)",
    "v4_outside_v5": "v4 crown outside the 2024 v5 survey, still drawn",
    "v4_not_continued": "v4 crown no current crown continues; the successor is the tree its representative record belongs to now",
    "deleted_pointcloud_false_positive": "removed in Sep 2026 before the 9 Sep release: the 2024 point cloud showed no tree at this LiDAR detection (roof, vessel, crane or water); no successor",
    "seeded_crown_retired": "a crown drawn from a record in v5.2 that a reviewer moved to another crown; the successor is that record's tree",
    "C#####": "a reviewer correction, see data/corrections-applied.json"
  },
  "number_format": {
    "pattern": "^T[0-9A-HJKMNP-TV-Z]{7}$",
    "alphabet": "0123456789ABCDEFGHJKMNPQRSTVWXYZ",
    "check": "Luhn mod 32 over the 6 characters after T",
    "input": "any case; spaces and hyphens ignored; I and L read as 1, O as 0",
    "url": "https://alto.tfwelch.com/tree/{number}"
  },
  "counts": {
    "keys": 19376165,
    "by_type": {
      "tree_id": 6238420,
      "seg_key_v4": 5576618,
      "number": 4200336,
      "seg_key_v5": 3352852,
      "tree_id_deleted": 7405,
      "seg_key_seeded_v52": 534
    },
    "by_status": {
      "current": 16090609,
      "member": 2038080,
      "retired": 1058072,
      "split": 189399,
      "merged": 5
    },
    "files": 65536,
    "bytes": 401366913,
    "largest_file_bytes": 7737
  }
}