What an Honest Tree Inventory Looks Like

Most council tree inventories include trees that may not exist, miss trees that definitely do, and carry data fields that no one updates. The aspiration was a comprehensive record. The reality is a hybrid of surveyed data, removed trees that were never deleted, and field updates that never made it back.

An honest inventory is narrower than the aspirational version, and more useful for it.

What honesty means here

Honesty in this context means three things: every tree in the inventory probably still exists, every tree that should be in the inventory probably is, and every field on the record is one that someone actually maintains. Honest does not mean perfect. It means the inventory does not pretend to know things it does not.

A 5,000-tree inventory with reliable basic data and currency on a small set of fields is more useful than a 12,000-tree inventory with stale data and many unmaintained fields.

Trees that probably still exist

Existence drift is the most common quality problem in tree inventories. Trees removed by contractor in 2019 still appear in 2026. Trees from a one-off audit that never made it through the council's removal program are still listed. Old plantings that died and were replaced are recorded twice.

The fix is to require a status field — active, removed, replacement required — and to make removal events update it. Even a quarterly review against the removals contractor's job list, comparing against trees flagged "still active" in the inventory, will surface most of the drift.

Trees that should be in the inventory probably are

The reverse drift — missing trees — is less visible but just as common. Trees planted by community groups, trees that grew naturally on reserve land, trees that were in scope of an audit but missed, trees adopted from developer handovers without a proper transfer process. These quietly accumulate as a parallel population outside the register.

The fix is harder. Regular tree audits are expensive. Pragmatic alternatives include: capturing newly planted trees from the planting program record, capturing newly identified trees from inspection workflows, and capturing trees from handover processes for new estates.

Fields that someone actually maintains

The hardest discipline in an honest inventory is admitting which fields are not maintained. Tree height, canopy spread, structural details, ownership notes — these often appear on the record because they were on the survey form. They are often not updated by anyone.

A field on the inventory that is not updated is worse than no field at all. It looks current but is stale, and downstream users will make decisions on it.

An honest inventory either confirms each field has a maintenance pattern (who updates it, on what trigger), or removes it from the routine record and moves it to a separate one-off-survey table where its stale-ness is obvious.

The minimum honest inventory

The minimum set of fields that most councils can actually maintain:

• Asset ID
• Location and GIS reference
• Species (genus + species)
• Broad type (street, park, reserve, sportsground)
• Status (active, removed, replacement required)
• Latest known condition (with date)
• Latest risk band (with date)
• Last inspection date
• Next inspection date
• Outstanding actions

Other fields can sit alongside this minimum, but as supporting data with their own maintenance pattern, not as core register fields.

Why honesty produces a better register

An honest inventory does not look as impressive as an aspirational one. It usually has fewer trees, fewer fields, and explicit gaps. The trade-off is that the data it carries is reliable. Decisions made from it are defensible. The team using it knows what it can be trusted for.

That is much harder to achieve from a register that aspires to completeness but quietly does not deliver it.