This document outlines an Urban Site Index (USI) system for assessing street tree planting sites on a large scale. It describes using field observations to assign a numeric score from 0-20 to quantify site quality factors like soil compaction, development, and street characteristics. Site evaluations are categorized and corresponding tree size classes are assigned. A master planting design process is proposed using these evaluations, a community map, and species assignment guidelines to systematically plan future street tree plantings across an entire community regardless of current conditions. Benefits include long-range planning, reduced guesswork, monitoring opportunities, and buy-in from residents and nurseries.
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The Ohio Master Planting Design: From Site Assessment to Plan
2. Ohio Division of Forestry
Urban Forestry Assistance Program
Steph Miller
Alan Siewert
3. Ohio 2000’s
• Aging Tree Commissions
• Knowledge
• Experience
• Retirements
• Emerald Ash Borer
• The Great Recession
Photo: Dr. Dan Herms, Ohio State University
4. Problem Solving Criteria
• Simple
• Non-foresters
• Cheap
• Fast
• Easy to understand
• Systematic
• Large scale
5. What Do We Really Need
For Large Scale Sites?
• Identify Site Constraints
• Treelawn Width
• Overhead Utility
• Soil
• Salt/Traffic Pattern
• Traffic Use/Parking/Curbing
6. Urban Site Index
USI
• Site Quality
• Compaction
• Structure
• Soil Health
• Salt/Traffic Pattern
Quantitative/Measurable
Use Field Data & Score Sheets
8. Urban Site Index
• A rapid assessment process to quantify
the severity/quality of street planting
sites
• Based on easily obtained field
observations
• Results in a numeric assessment: 0-20
9. Urban Site Index
8 Observations
4 Soil Observations
• Scored 0-3
4 Street observations
• Scored 0-2
11. Vegetation
0 Bare dirt, gravel or some sort of pavement
1 Sparse weeds with some dirt showing
2 Patchy grass and weeds
3 Lush grass some weed ok
12. Surface Compaction
0 No soil, pavement
1 Hard, like walking on office carpeting
2 Some give, like walking on padded carpet
3 Cushioned give, like walking on deep pile
padding
13. Probe/Shovel Penetration
0 No soil, pavement
1 Goes in, but not
completely
2 Goes in, but requires lots
of effort
3 Goes in fully with ease
14. Soil Development
0 No soil, pavement
1 No top soil, un-layered sub soil, or clear
separation between top & subsoil
2 Layering in soil from old native soil
3 Good, deep topsoil with only the A horizon in
the probe
22. Site Evaluation Needs
• Identify Site Constraints
• Treelawn Width
• Overhead Utility
• Soil
• Salt/Traffic Pattern
• Traffic Use/Parking/Curbing
Large Scale Sites
23. Size Classes
• Large Site
• 8+ feet wide
• No overhead primary electric
• Medium Site
• 6-8 feet wide
• Small Site
• 4-6 feet wide
24. Parking/Curbing
• Primary Site
• Curb & Sidewalk
• Space clearly defined
• Secondary
• Only curb or sidewalk
• Lose space definition
• Tertiary
• No curb
• No sidewalk
• No space definition
25. Think Large Scale
Colt St S Brown Ln Saints Way 2 2 2 12 1 2 2 14 L 1
• End Block may be 7-11 Trees
• End Block may be change in USI, Size Class, or Priority
26. Site Evaluation Categories
Utilizing Score Sheet
Good Quality
Site
16-20
Intermediate
Quality Site
12-15
Poor Quality
Site
9-11
No Tree
0-8
Large Tree Large Tree Large Tree
Medium Tree Medium Tree Medium Tree
Small Tree Small Tree Small Tree
29. Master Planting Design
• Roadmap for the future
• Plan for the entire community…
…regardless of what’s there now
How Might We Do This?
30. Supply List
• Community Street Map
• Labeled with street names
• Labeled N/S/E/W if applicable
• Block numbers
• Scale
• USI Data Collection Sheet
• Colored Markers
• Pencil
• Soil Probe/Shovel
31. Site Evaluation Categories
Key
Good Quality
Site
16-20
Intermediate
Quality Site
12-15
Poor Quality
Site
9-11
No Tree
0-8
Large Tree Large Tree Large Tree
Medium Tree Medium Tree Medium Tree
Small Tree Small Tree Small Tree
37. MPD Tree List
 Good Site: Large Species
• Wide Treelawns
• Low/No Road Salt
• Good Soils
Tree Selection
Large Species
Match Complimentary Small/Medium Species
only @ overhead utility
Push the Envelope to increase diversity
May plant trees that aren’t usually on street tree lists
38. Community Tree List
Good Quality/Large Site
Large Tree Medium Tree Small Tree
Tulip poplar,
Liriodendron tulipifera
Magnoliaceae
Umbrella magnolia, Magnolia
tripetala Magnoliaceae
Saucer magnolia
Magnolia x soulangiana
Magnoliaceae
Sugar or Black Maple,
Acer saccharum or
nigrum Aceraceae
Striped maple,
Acer pennsylvanicum
Aceraceae
Pagoda or Flowering
dogwood,
Cornus alternifolia or florida
Cornaceae
Red Maple,
Acer rubrum Aceraceae
Sycamore maple,
Acer pseudoplatanus
Aceraceae
Fringetree,
Chionanthus virginicus
Oleaceae
39. Assign Species to Segment
2 Segments between Family
4 Segments between Genus
6 Segments between Species
41. 2 Segments
Same Family
Ulmaceae (Elm)
Celtis/Ulmus/Zelkova
4 Segments
Same Genus
Ulmus
americana & parvifolia
6 Segments
Same Species
Ulmus parvifolia
1 2 3
4 5
6
4
Hack-
berry
Elm
AElm
L
LElm
42. Assign Species
2 Segments between Family
4 Segments between Genus
6 Segments between Species
• Breaks up similar trees
• Means to test diversity
• Only use cultivar if it has a bearing on
site constraint
• i.e. an upright cultivar near a car dealership
47. Benefits of
Master Planting Design
• Long-Range Planning
• Guess Work out of
Annual Planning
• Buy-in from Residents
• Planning with Nurseries
• Insect/Disease/Weather
Monitoring
• USI Truthing