How far should trees be planted from a house in Oklahoma City?
In short: About a fifth of the Oklahoma City metro is under tree canopy, with eastern redcedar, slippery elm and western soapberry the most common species. Oklahoma City's planting guide keeps medium and large trees at least 30 feet from buildings. Most tree roots are shallow but spread well beyond the canopy, which is why trees can dry clay soil next to a footing.
This page collects Oklahoma tree data that matters for foundations. For how trees dry clay and cause settlement, see trees and roots.
How much tree canopy does the OKC metro have?
The Association of Central Oklahoma Governments (ACOG) commissioned a canopy assessment of the Oklahoma City metropolitan area in 2019 1.
| Measure | Value |
|---|---|
| Study area | 536.4 square miles (343,314 acres) 1 |
| Tree canopy cover | 22.4% (76,903 acres) 1 |
| Estimated number of trees | About 65 million 1 |
| Species recorded | 74 1 |
Most common species
| Species | Share of trees |
|---|---|
| Eastern redcedar | 13.2% 1 |
| Slippery elm | 9.7% 1 |
| Western soapberry | 9.6% 1 |
What are the official planting distances?
The City of Oklahoma City's planting guide sets these distances 2:
- Medium and large trees: no closer than 30 feet to buildings or structures 2.
- Trees listed as suitable near water lines: 5 feet from lines 4 inches in diameter, or 10 feet from larger lines 2.
- Medium and large trees should never be planted under overhead utility lines 2.
- Street trees: at least 10 feet from overhead lines and power poles (15 feet recommended) and at least 5 feet from underground utility lines 2.
Oklahoma State University (OSU) Extension gives a rule based on tree size: plant at least half the mature canopy width away from the home, and keep fast-growing or weak-wooded trees well away from buildings 3.
Where do tree roots grow?
| Fact | Source |
|---|---|
| Most trees grow a fibrous root system in the upper 24 inches of soil | OSU Extension 4 |
| The top 12 inches of soil does the most water and mineral uptake | OSU Extension 4 |
| Pecan, walnut, some pines and some oaks develop a deep taproot | OSU Extension 4 |
| Roots often spread up to 3 times the canopy width | OSU Extension 4 |
| In shallow soil over clay, roots may spread up to 5 times the canopy width | OSU Extension 4 |
| Studies show roots spreading 4 to 7 times the dripline radius | Iowa State Extension 5 |
| Roots rarely grow below about 4 feet, though deeper reports exist | Iowa State Extension 5 |
The dripline is the outer edge of a tree's canopy. Because roots reach far past it, a tree that looks well clear of the house can still draw water from soil along the foundation, a process described in tree-root desiccation settlement.
What species traits does OSU Extension list?
OSU Extension's selection guide lists these traits for trees common in Oklahoma yards 3:
- Silver maple: fast growth, brittle wood and a shallow root system 3.
- Eastern cottonwood: grows too large for typical landscapes and has surface roots 3.
- Sweetgum: needs damp, rich soil, is not very drought tolerant and may have shallow roots 3.
- Pecan: needs deep, rich, moist soil and drops large limbs as it ages 3.
- Post oak and blackjack oak: do not tolerate compaction or nearby construction; post oak is also listed as not tolerating grade changes 3.
- Bur oak: tolerates dry clay soils but eventually grows very large 3.
- Lacebark elm: described as extremely tough and drought tolerant 3.
The oak traits are relevant when excavation is planned beside a house, such as for steel push piers or drainage work, since digging and compaction near the root zone can injure these species 3.
Why do trees matter on Oklahoma clay?
Clay soils across central and eastern Oklahoma swell and shrink with moisture (see shrink-swell and active zone). A tree concentrated near one side of a house adds uneven drying on that side, and removing a large tree can lead to post-tree-removal heave as the soil rewets.
Related
- Trees and roots
- Tree-root desiccation settlement
- Post-tree-removal heave
- Tree management
- Root barriers and moisture control
- OKC metro region
Common questions
What are the most common trees in the Oklahoma City metro?
A 2019 regional canopy assessment found eastern redcedar (13.2%), slippery elm (9.7%) and western soapberry (9.6%) were the most common species.
How much of the OKC metro is covered by tree canopy?
The 2019 assessment of a 536-square-mile study area measured 22.4% tree canopy, with an estimated 65 million trees of 74 species.
How close to a house can I plant a large tree in Oklahoma City?
The city's planting guide says medium and large trees should be planted no closer than 30 feet to buildings or structures.
How deep are most tree roots?
OSU Extension says most trees grow a fibrous root system in the upper 24 inches of soil, and roots can spread up to three to five times the canopy width.
Sources
- Oklahoma City Metropolitan Area Tree Canopy Assessment (Executive Summary) Association of Central Oklahoma Governments
- Trees and Plants for Oklahoma City City of Oklahoma City
- Selecting Deciduous Trees for Oklahoma Oklahoma State University Extension
- Getting to the root of good tree health Oklahoma State University Extension
- Tree Root Systems Iowa State University Extension and Outreach
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