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Aotearoa Long-term Tree Observatory

An open record of Auckland’s trees from the Better Places Lab: what each source recorded, what the 2024 LiDAR survey measured, and what ALTO estimates, each with its method.

Data releaseTool 0.2.12What changed

ALTO brings Auckland’s tree records, the 2024 LiDAR survey (an airborne laser survey), earlier surveys and aerial imagery together. For each tree it estimates size, growth form, root space and yearly benefits, and links earlier canopy records where it can. Select a tree to see its source data, its measurements and the estimates, each marked as an estimate. How ALTO is made.

Release totals

…map markers

…LiDAR crowns 3 m or taller

…markers found in the 2024 LiDAR survey

…map markers linked to Schedule 10

…benefits (estimate; sensitivity scenario)

…runoff avoided (estimate)

…carbon stored (estimate)

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A tree’s data

Tree panel: size, survey history, benefits and identifiers. Tree page: every source record, measurement, method, photo and a citation. Area, in the left panel: totals for Auckland, a local board, the map view or a property. Species maxima: the largest measured tree of each species, by height, crown spread and crown area. Bulk data and research partnerships: Email the Better Places Lab (t.welch@auckland.ac.nz).

KYTE (Know Your Tree Explorer) is ALTO’s field app: photograph a tree, match it to its ALTO record and add what you see; accepted visits appear on the tree’s page. Open KYTE.

Methods and sources

The methods explain how ALTO finds trees, estimates their dimensions and benefits, links surveys through time, and tests its predictions. They include the assumptions, test results and gaps still to resolve. How ALTO is made gives the overview; Methods lists every release. Model code and documentation.

How crowns are drawn

Crowns are segmented from the 2024 LiDAR survey and aerial imagery (release 5 onwards). Earlier detections, dimensions and ground visits stay in each tree’s full record.

Council notable-tree positions that are not yet verified stay separate from automatic crown links. A crown outline can still split one tree or join several. Methods for release 5.2.

Coverage and limitations

LiDAR-detected trees are labelled by how strong the evidence is: very likely, probable or possible. A possible tree may be a hedge or a large shrub. The “Include possible and unverified detections” switch under Filters › Link status hides them.

The current map covers metropolitan Auckland. Earlier canopy records depend on historic survey coverage and successful matching. Records outside the 2024 survey’s crowns keep their earlier measurements. Unmatched records remain available for review. Trunk diameter and roots are estimated; field measurements would improve both. Species names come only from source records. Where none exists, ALTO estimates the growth form (evergreen broadleaf, deciduous broadleaf, conifer, or palm, cabbage tree or tree fern) and marks it as an estimate.

Release provenance

Release

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Release metadata (JSON)

Corrections

Email the Better Places Lab (t.welch@auckland.ac.nz) to correct a record, with the tree number and what is wrong.

Sources and credits

Developed by the Better Places Lab (Dr Timothy F. Welch), Te Pare School of Architecture and Planning, Waipapa Taumata Rau | University of Auckland.

Tree records from Auckland Council: the tree register, including Auckland Transport and Parks trees (retrieved June 2026), the Unitary Plan notable trees, and kauri survey records (Bio Info Team, Environmental Services; not a complete record, verify before relying on it); and © OpenStreetMap contributors (ODbL). LiDAR surveys of 2013, 2016–18 and 2024 and aerial photographs since 2010, licensed by Auckland Council, Regional Software Holdings Limited and others, sourced from Toitū Te Whenua LINZ (CC BY 4.0). Parcels and building outlines from LINZ (CC BY 4.0); conservation land, Crown Copyright: Department of Conservation Te Papa Atawhai 2026 (CC BY 4.0); local boards from Stats NZ – Tatauranga Aotearoa (CC BY 4.0). Basemaps: Powered by Esri, and © OpenStreetMap contributors. Species references from i-Tree (USDA Forest Service and cooperators). Photographs from KYTE contributors. Some tree pages link to the record for the same tree on the New Zealand Tree Register (New Zealand Notable Trees Trust). Every source, its licence and a link to the original: Sources and credits.

Cite the map: Welch, T. F. (2026). ALTO: Aotearoa Long-term Tree Observatory. Better Places Lab, University of Auckland.

Land type (the Land type filter and colours, and property summaries) is inferred from parcel, zone, park and conservation-land records and OpenStreetMap golf courses, island roads and addresses; ownership records are not used. Each dataset is listed on Sources and credits.