Soil Volume Minimums for Street Trees Organized by State/Province

At DeepRoot, we promote large volumes of non-compacted, biologically active loam as essential for street tree health and longevity. Back in 2014, we wanted to recognize the municipalities that were rethinking the vital role trees play in the health of our planet and population, by creating a comprehensive list of soil volume minimums for cities and states in the US and Canada. Since then, there have been 15 additions and amendments to soil volume minimums across North America. Today we’re happy to share that we’ve updated this table for 2020.

Urban foresters generally adhere to the following minimums: 300 cubic feet for small trees, 600 cubic feet for medium trees, and 1,000 cubic feet for large trees.

In the table below, you can organize the information by different criteria such as city, state/province, country, and soil volume.

Here are the five most recent standards that have been added or amended to the list.
– San Diego, CA (Jan. 2019)
– Aspen, CO (Jan. 2019)  amended
– Tigard, OR (May. 2019)
– Alexandria, VA (Feb. 2019)  amended
– Minnesota (Jan. 2020)
CountryState/ProvinceCity or CountySoil volume minimumOfficial DocumentationNotesLast amendment
CanadaAlbertaEdmontonSmall tree: 11m3
Large tree: 11m3
Design and Construction LandscapingJune, 2017
CanadaBritish ColumbiaKelowna4m3City of Kelowna Design StandardsSee setion 6B page 8 of 92012
CanadaBritish ColumbiaVictoria12m3City of Victoria Subdivision and Development BylawSee section 1.2.6., page 6.2012
CanadaBritish ColumbiaVancouver0.3 m3 or 0.6 m3 (preferred)Urban Forest Climate AdaptationSee section 4.2, page 41May, 2017
CanadaBritish ColumbiaSurreysmall: 15m3 (10m3 shared) medium: 20m3 (15m3 shared) large: 30m3 (20m3 shared)City of Surrey Shade Tree Management PlanSee page 292016
USCaliforniaEmeryvillesmall:600 ft3 medium: 900 ft3 large:1200 ft3Climate Resilient Street TreesSee download in link for street tree species that are climate resilient (2016)2020
USCaliforniaSan DiegoSmall: 600 ft3
Medium: 1,000 ft3 Large: 1,500 ft3
County of San Diego BMP Design ManualSee section K, page 31January, 2019
USColoradoAspenSmall: 240 ft3 Medium: 600 ft3 Large: 1200 ft3Water Efficient Landscaping StandardsSee section 4.1 Soil Criteria and Appendix F (tree soil information chart)January, 2019
USColoradoDenver750ft3 to 1000ft3 per treeCity and County of Denver Ultra-Urban Green Infrastructure GuidelinesSee section 82016
USFloridaPompano BechSmall: 450ft3 Medium: 820ft3 Large: 1280ft3Pompano Beach Zoning CodeSee section J, 3 language and ratio graph2020
USFloridaSmall: 10 ft2 Medium: 20 ft2 Large: 30ft2Urban Design for a Wind Resistant Urban ForestSee chart on page 4February, 2017
USGeorgiaDecaturVery small:108 ft3 Small: 300 ft3 Medium: 675 ft3 Large: 1,200 ft3 City of Decatur Tree Canopy Conservance OrdinanceSee page 12May, 2014
USGeorgiaAthens-Clarke CountySmall: 200 ft3 Medium: 450ft3 Large: 800 ft3
Best Management Practices for Commmunity TreesSee Page 12. more on Athens-Clarke County: https://www.athensclarkecounty.com/273/Tree-Ordinance2005
CanadaOntarioGuelphSmall: 18m3 Medium: 36 m3Streescape ManualSee page 562017
USIdahoBoise500m3DOWNTOWN BOISE STREETSCAPE STANDARDS & SPECIFICATIONS MANUAL See page 26. Section 3: Suspended Paving Systems2016
USIllinoisChicagoDepth of 3ft of soil. 24 ft2 surface areaChicago Landscape OrdinanceSee page 412000
USMinnesotaSmall: 400ft3
Medium: 800ft3
Large: 1,200ft3
Minnesotra B3 Guidelines: New Buildings and Major Renovations Version 3.2See page 49, Guideline S.4: VegetationJan, 2020
USNorth CarolinaCharlotte274ft2 for sidewalk trees 200ft2 for parking lot trees Assuming 3’ of soil depth we can say 822 cf for sidewalk trees and 600 cf of soil for parking lot treeCharlotte Approved Tree OrdinanceSee page 17, Section 2196 2 (parking areas) b-2September, 2010
USNorth CarolinaDurhamSmall: 150 ft2 Medium: 250ft2 Large: 350ft2Landscape Manual for Duaham, NCSee page 39, See page 41-106 for type of tree and designated volumeApril, 2013
USNorth CarolinaRaleigh600ft3North Carolina Street Design Manualsee page 56, Section 6.18.1 and 6.18.2January, 2014 (however link says 2017 in the website link)
USNew YorkNew York City1.6- 2.0 ft3/ft2NYC Design GuidelinesSee page 153, Section 72010
USOhioClevelandSmall: 300 ft3 Medium: 600 ft3 Large: 1000f t3Cleveland Guide for Species Selectionsee page 2, Section AAugust, 2015
USOhioColumbus1000 ft3 (single) 750 ft3 (shared)Downtown Streetscape StandardsSelect PDF, see page 37, section 5.6 October, 2015
CanadaOntarioGuelphSmall: 18m3 Medium: 36 m3 Large: 50m3City of Guelph Downtown Streetscape Manual & Built Form StandardsSee page 56 under Tree PlantingJanuary, 2014
CanadaOntarioMarkhamSmall: 15 m3 Medium: 23m3 Large: 30 m3

Markham Streetscape Manual: Trees for Tomorrowsee page 14, spatial requirements in design guidelinesJanuary, 2009
CanadaOntarioKitchenerSmall:17m3 (single ) 11m3(shared)
Medium: 28m3(single) 18.5m3(shared)
Large: 45m3(single) 30m3(shared)
Development Manualsee page 3 of Appendix B2015
CanadaOntarioOakville30m3 (single) 15 m3 (shared)Oakville Forest Management Plansee page iii, and Appendix CSeptember, 2012
CanadaOntarioToronto530 ft3Toronto Green Standard V3See Ecology Section 1.1. Tree Planting and Soil VolumeMay, 2018
CanadaOntarioYork RegionSustainability Performance of New Development York RegionJuly, 2013
USOregonTigard400ft3 to 1,000 ft3 Urban Forestry ManualSee page 12-1, Section 12 May, 2019
USVirginiaAlexandria450 ft32019 Landscape GuidelinesSee page 36February, 2019
USVirginiaFairfax County700 ft3 (single) 1200 ft3 (double)Fairfax County Land DevelopmentSee page 12-402018
USWashington D.C.Small: 600 ft3
Medium: 1,000 ft3
Large: 1,500 ft3
Green Infrastructure Design StandardsSee page D-23, See section 47.7.16-Jul
USWashingtonSeattle1200ft3 per treehttps://streetsillustrated.seattle.gov/design-standards/street-trees/see design guide, at the bottom of the pageJune, 2017
USWest VirginiaSmall tree: 500 ft3 Medium tree: 750 ft3 Large tree: 970 ft3

West Virginia Department of Environmental Protection recommendedSee page 7, table2008
In progress of developing a soil volume minimum
CanadaOntarioKingstonhttps://www.cityofkingston.ca/residents/environment-sustainability/nature-forests-gardens/urban-forest-management-plan
CanadaOntarioKitchenerhttp://www.kitchener.ca/en/livinginkitchener/UrbanForestry.asp
CanadaOntarioMississaugahttp://www7.mississauga.ca/Departments/Rec/future-directions/pdf/2019-plans/2019%20ParksForestry%20Master%20Plan_FINAL.pdf

Right now, this list only contains cities in North America – there are no soil volumes for trees that we know of in the United Kingdom – though we hope that will change.

Setting soil volume minimums for street trees tacitly enforces the message that business as usual as far as tree planting is concerned isn’t good enough. We need to continue rethinking how we plan for our urban forests and the role of green infrastructure in the built environment.

Take a look to see if your city, state, province, or, county has been added! Should your city or town be on this list, or do you know of any others that we missed? We want to hear about your goals for growing healthy trees in your community. Please email us at [email protected]

Header image credit: carlos aranda.

12 comments

  1. This is not research based information. It is people who copied other peoples work who go it from Cornell irrigation work. In other words the soil volume info only applies to Cornell and other similar places that do not irrigate trees

    • Hi John, I’m not sure I understand your comment. Which information is not research-based? This is simply a list of all the places that we’re aware of that have implemented soil volume minimums for street trees (defined as trees in the public right of way). Are you saying that tree growth/health is not tied to their access to lightly compacted quality soil?

  2. Here in Wales, at Wrexham County Borough Council, i have managed to put in place a Local Planning Policy which states “Where tree planting is proposed within hard surfaced areas (e.g. parking areas and footpaths) the size of the planting pits should be sufficient to provide an adequate volume of soil to support the eventual size of the the planted tree(s)”. Unfortunately, when this policy was adopted i didn’t have sufficient knowledge to stipulate volumes that we would require, however ever since i have been asking for a minimum of 25 metres cubed of good quality planting soil for large growing trees, 15 for medium sized trees and 8 metres cubed for small growing trees, with these figures being reduced by a third for shared pits. When we come to revise our local planning note on trees & development, i will be putting in these requirments.

    With regards to CU soil i have been asking for four times the above sizes, as CU soil contains 80% stone therefore the rooting volumes jhave to increase in order to provide the same amount of soil.

    Its amazing the number of landscape architects and developers that have been actively fighting this policy as they do not want to spend money. Traditionally in Britain, the vast majority of developers have viewed landscaping as something that municipal planning forces on them and they spend as little on the hole as they try to do with the trees to be planted. The old adage of spend a £100 on the hole and £10 on the tree seems to have been forgotten by so many in this industry. Its such a shame that a huge percentage of the landscape architects over here in Britian do not keep up with continual professional development and still believe that a large tree will survive in a hole with 1 metre cubed of soil. In the past here, a large number of trees were planted in concrete rings in hard surfaced areas, which you would be lucky to get 0.5 metres cubed of soil in, these are what i call concrete tree coffins, and any tree planted in a hard surfaced area which does not provide sufficient volume of soil is a tree coffin.

    The lack of understanding of the basic requirements of trees i.e sufficient rooting volume of decent soil by a hell of a lot of landscape architects over here in Blighty is so depressing. Thus having minimum rooting volume policies is such a good idea. I applaud Deeproot for highlighting who actually has policy on rooting volumes for trees. Lets hope more get this type of policy adopted in their municipalities.

    • Moray, thank you so much for commenting. It’s a slog trying to educate and get everyone on the same page about this fundamental truth: trees need soil. Even if you weren’t able to specify a soil volume minimum in Wrexham the first time around, you’ve laid some important groundwork for future changes. Hopefully those will happen yet! Thanks for everything you’re doing for trees.

  3. I’m not sure that West Virginia should be included in the list. The EPA guidebook listed on their website is just that – a resource for people interested in reading it. To my knowledge, West Virginia has not truly embraced any recommended minimum soil volume requirements.

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