Introduction to STRATUM Model and Application

What makes STRATUM different?

Street trees, not entire urban forest Costs, not only benefits Management tool, not only for advocacy Tree inventory-based, not GIS Answers the question: do the accrued

benefits of street trees outweigh the cost of their management?

StructureStructure

FunctionFunction

ValueValue

Management Management NeedsNeeds

The Foundation: Reference City Research

Regional Tree Guide studies to develop growth models of representative street trees and their dimensions as a basis for Benefit-Cost Analysis.

Reference City Research

Collected local street tree data

Analyzed growth rates and dimensions

Estimated magnitude of annual benefits

Priced benefits Priced tree care costs Calculated net annual

benefits, benefit-cost ratios

Tree Size, Growth, and Functionality

Sweetgum

0

2

4

6

8

10

12

14

16

18

20

0 5 10 15 20 25 30 35 40 45 50

Years

Bo

le &

To

tal

He

igh

t (m

)

Santa Monica

Modesto

Claremont

70%40% 26%

Sweetgum in three climate zones at age 40

Inland Empire Coastal S. CA Central Valley

Research Process— Benefits

Heating & Cooling Energy - Regional market prices ($0.095/ kWh, $0.97/therm)

Carbon trading credits - CO2 ($15/ton)

Air Pollutants - Transaction costs, damage value and control cost of emissions ($1-15,000/ton)

Stormwater Runoff - Retention/detention costs ($0.005/gal)

Residential Property Increase - Average resale price (median sales price = $254,000)

Research Process—Costs

Planting Pruning Removal and disposal Pest and disease control Irrigation Infrastructure Leaf litter cleanup Liability Administration

The STRATUM Application

Define Costs

Define City

Define Benefit Prices

StructureStructure

FunctionFunction

ValueValue

Management Management NeedsNeeds