---
title: a single tree can be a place
canonical_url: https://ensurance.app/guide/a-single-tree-can-be-a-place
markdown_url: https://ensurance.app/guide/a-single-tree-can-be-a-place.md
subtitle: "the smallest grain — a tree, a spring, a garden bed — and the grid that holds it"
category: natural-capital
---

# a single tree can be a place

*the smallest grain — a tree, a spring, a garden bed — and the grid that holds it*

A **heritage tree** is an individual tree that a city, county, or other public body has formally listed for its age, size, species, history, or beauty, so that removing it takes more than an ordinary permit. Portland, Oregon, runs one of the best-known programs, under City Code 11.20.060. A Heritage Tree Committee of volunteers and city staff reviews nominations, the Urban Forestry Commission votes on them, and City Council designates trees by ordinance. A tree on private land is designated only with the owner's consent, and the designation binds later owners. Portland has roughly 300 heritage trees, with new ones added most years. Rules vary from city to city. Some registers are honorary and carry no legal protection at all.

What a designation does: Portland's code makes it unlawful to remove, prune, or injure a heritage tree without prior written authorization, and the city's heritage tree page says removal is approved only if a tree is dead, dying, or dangerous. What it does not do: it does not stop a tree from dying, and Council can remove a designation it finds no longer appropriate. A heritage listing is strong protection against a chainsaw. It is not a guarantee of water, soil, and room to grow.

If you came here hoping your own tree already has an account in this protocol, it almost certainly does not. No account exists today for most single trees. The door is to [open or propose one](/agents/create?from=guide).

A tree already exists and already depends on other living things: the fungi at its roots, the water table under it, the trees beside it that break the wind. It does that whether or not anyone lists it. [**Ensurance**](/?from=guide) is how the place you name gets funded to keep working. It is not the tree.

## a tree is a place in its own right

A heritage register treats a tree as an object worth protecting. This series treats it as something slightly different: a **place**. One tree has an address, a canopy that shades a patch of ground, a root zone that holds a patch of soil, and a set of living things that use it — the birds that nest in it, the insects in its bark, the people who sit under it.

That makes a single tree the smallest grain at which a place account works. It is a point, not a polygon. You do not need a deed or a survey to name it. You need a location and a reason.

Other single-pin places work the same way:

- **A spring.** One seep where groundwater reaches the surface, often the only open water for a long way.
- **A garden bed.** A few square meters of soil someone has kept in good heart for years.
- **A nest tree.** The one snag a pair of raptors comes back to.
- **A grave or a gathering spot.** A place that matters because of who is there or who came before.

None of these needs to be big to count.

## how a pin becomes an area

A pin on a map is a coordinate: a latitude and a longitude, with no size. A tree has a size. The protocol bridges that gap with **H3**, an open-source grid of hexagons that Uber released in 2018. H3 covers the earth in hexagons at 16 resolutions, numbered 0 to 15. Each cell has about seven children at the next resolution, which roughly nest inside it.

That nesting is what lets a point become an area at whatever grain fits. The app stores a place's representative cell at resolution 9, a cell of about 0.1 square kilometers. It displays the coarser resolution 8 cell, about 0.74 square kilometers, in public.

| what you have | what the app does | why |
|---|---|---|
| a pin on one tree | stores the fine cell that contains it | so the account knows where it is |
| a public page | shows the coarser parent cell | so a stranger cannot walk to the door |
| a larger place | the same grid, at a coarser resolution | so the tree and the basin use one map |

The privacy rule matters most at this size, because a single tree is often in someone's yard. Homes, nest sites, graves and sacred places are never pinned in public. The app stores fine and shows coarse. [The home you won't pin](/guide/the-home-you-wont-pin?from=guide) covers the reasoning; the short version is that a public map of exact backyard locations is a map nobody asked for.

## what the tree depends on is larger than the tree

Name one tree and you have already named its neighbors. The tree draws on soil that runs under the fence. It draws on a water table fed by rain and snowmelt across a whole slope. Its canopy is part of a larger canopy that sets the temperature and humidity it grows in. Place depends on place.

So the tree sits on a ladder, even if nobody climbs it. Here it is with live accounts in Colorado's Crystal River valley:

| size | place | account |
|---|---|---|
| one tree | a cottonwood on the riverbank | none yet; [open or propose one](/agents/create?from=guide) |
| 54 acres | the beaver wetland at Marble | [marble-wetlands-preserve.avlt](/marble-wetlands-preserve.avlt?from=guide) |
| one reach | the Crystal River through Marble and Redstone | [crystal-river.basin](/crystal-river.basin?from=guide) |
| a basin | the whole Colorado River | [colorado-river.basin](/colorado-river.basin?from=guide) |

The cottonwood row is illustrative. The other three are real account pages, and the land under the wetland is held under a conservation easement by Aspen Valley Land Trust, per the account's own description.

**What stays the same** up the ladder: each rung is an account of the same shape. It has an address, it can hold and receive funds once a wallet is deployed, and a person confirms each action unless the keeper has switched on a program. The Marble wetland account has not deployed one yet. Several accounts can serve the same place, and none of them owns it.

**What changes** is who can act and what can be measured. One person can tend one tree and see it every day. A land trust tends 54 acres. A basin has no single keeper at all; it runs through compacts, councils, and many smaller accounts. A tree's health is read by someone standing under it. A basin's is read from gauges and satellites.

The tree does not become less of a place because the basin is bigger. The basin does not make the tree redundant. If you can tend the tree, name the tree, and let the larger accounts carry what the tree depends on.

:::johnson
**the smallest place is still a whole place.**

One tree, one spring, one garden bed can each hold an account. No account exists for your tree yet; you can open or propose one.

[propose an account for a tree →](/agents/create?from=guide)
:::

## heritage registers and accounts are different tools

A heritage tree register and a place account do different jobs, and they can sit side by side.

| | heritage tree designation | place account |
|---|---|---|
| who creates it | a public body, by its own process | anyone, by proposing it |
| what it does | limits removal | names the tree and, once a wallet is deployed, can receive funds for its care |
| who decides | the city, under its code | the people who keep the tree; a person confirms each action unless the keeper has switched on a program |
| what it cannot do | water the tree | override the city's code or the owner's rights |

A register is law. An account is not. Nothing about an account changes who owns the land a tree stands on, or what the city's rules allow. If a tree is on someone else's land, it is their tree, and any account for it should start with their consent.

The two work well together. A city register says the tree should stay. An account gives the people who care about it a place to pool the money for an arborist, a watering schedule, or the mulch ring that keeps mowers off the roots.

## the next size up

A tree is a point. The next rung up is the first polygon with a legal edge: the parcel, where a titleholder can sign. [The parcel is the place you can sign for](/guide/the-parcel-is-the-place-you-can-sign-for?from=guide) picks up there. For the whole ladder, from one tree to a flyway, start at [what counts as a place?](/guide/what-counts-as-a-place?from=guide)

If you keep a tree, a spring, or a garden that matters and want to talk it through, [write to us](/contact?from=guide&topic=ppp-place) and name the place in the first line.

## frequently asked questions

### what is a heritage tree?

A heritage tree is an individual tree formally listed by a city or other public body for its age, size, species, history, or beauty. In Portland, Oregon, City Council designates heritage trees, private trees only with the owner's consent, and the city says removal is approved only if a tree is dead, dying, or dangerous. Rules vary, and some registers are honorary.

### does a heritage tree designation protect a tree forever?

No. It limits removal, but a designated tree can still be removed if it dies or becomes dangerous, and a designation can be withdrawn. It also does not by itself pay for the care that keeps a tree alive.

### can I open an account for one tree?

You can open or propose one. No account exists today for most single trees. An account for a tree on land you do not own should start with the owner's consent, and a public page shows a coarse area, never the exact spot.

## sources

[City of Portland, heritage trees](https://www.portland.gov/trees/heritage) — the designation process and the city's statement that a heritage tree is approved for removal only if dead, dying, or dangerous.

[Portland City Code 11.20.060, heritage trees](https://www.portland.gov/code/11/20/060) — designation, owner consent for private trees, and the rule against removing, pruning, or injuring a heritage tree without prior written authorization.

[Oregon Encyclopedia, heritage trees of Portland](https://www.oregonencyclopedia.org/articles/heritage_trees_of_portland/) — the Heritage Tree Committee's review and the count of roughly 300 trees.

[H3, Uber Engineering](https://www.uber.com/blog/h3/) — the hexagonal hierarchical grid, open-sourced in 2018; 16 resolutions; about seven children per cell.

## the series

1. [what counts as a place?](/guide/what-counts-as-a-place?from=guide) — read first
2. [a single tree can be a place](/guide/a-single-tree-can-be-a-place?from=guide)
3. [the parcel is the place you can sign for](/guide/the-parcel-is-the-place-you-can-sign-for?from=guide)
4. [a watershed draws its own line](/guide/a-watershed-draws-its-own-line?from=guide)
5. [ecoregions, bioregions, and flyways](/guide/ecoregions-bioregions-and-flyways?from=guide)
6. [every place is already for something](/guide/every-place-is-already-for-something?from=guide)

## the three series

- [what counts as a place?](/guide/what-counts-as-a-place?from=guide) — place
- [what counts as a purpose?](/guide/what-counts-as-a-purpose?from=guide) — purpose
- [who counts as people?](/guide/who-counts-as-people?from=guide) — people
- [what do you want to ensure?](/guide/what-do-you-want-to-ensure?from=guide) — the series before these three