STRATUM:Overview & Process

Session Purpose

i-Tree

STRATUM Savvy

Community forest

management

What’s In Store for You?

Background

Process

Data Collection

Field Practice

STRATUM

Create a project

Inputs

Reports

Background

Center for Urban Forest ResearchUSDA Forest ServicePSW Research StationDavis, CA

To demonstrate new ways that trees add value - quality of life - to communities.

StructureStructure

FunctionFunction

ValueValue

Management Management NeedsNeeds

What We Need?

Value of trees to human health and well-beingIncreased investment in management

Planning integrated up-front, not as after-thought

Green and gray infrastructure working togetherIncreased return on investment and customer

satisfaction

Tools to quantify the value of trees

Tree Value

Trees are assets, management adds value by increasing return on investment

Heart of Sustainable FundingSufficient local budget appropriationEngage in outreach, public

relations, special eventsRegularly educate and lobby

community leadersDevelop clear argument to justify

budget:Resource assessmentResource value

STRATUM Helps You

Justify and leverage fundsHighlight benefits to publicPlan, prioritize, and budgetBenchmark progress

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.

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

STRATUM was designed to extend Reference City data to all communities within a climate zone

Reference City ResearchCollected 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

Sample Design

Reference city data collection is used to develop growth models of representative street trees and calculate benefits.Predominant species

18 – 25 species representing >65% of forest

Random sample of 35 – 70 trees per speciesStratified, minimum 40 year age range

Measurements25 field measurements for each tree, including:

Diameter-at-breast-heightTree heightCrown (bole) heightCrown diameterLeaf areaCrown shape Tree orientation and setbackCondition and locationPruning levelGrow space type and sizeHardscape damage

Vegetation Structure

---- Tree locations

Species Canopy cover

Leaf area Biomass Growth Mortality Diversity Health Site

Sequestration CO2 Released

Reduction in atmospheric

CO2

Bldg. data

Meteor. Data Shade

Air temp. Wind speed

RH

Regional Climate

Energy Heating Cooling

Emission Factors

Avoided Emissions

Air Quality Data

NOx, SOx, O3, PM10

Dry deposition

Air quality improvement

B.V.O.C. Isoprenes

Monoterpenes

Stormwater Runoff

Interception

Firewise Landscapes

Other

Aesthetics

Structure Hydrology Air Quality Energy & CO2

Fire Other

Research Process—Structural Analysis Data collection – 900 trees, 20 predominant species age, species, dbh, ht., crown dia., condition, digital

photos, foliar biomass samples, etc.

Calculate leaf area and foliar biomass

Regression models predict growth.

Research Process—Functional Analysis

Models use structural data

– (size at various ages).

To determine magnitude

of annual benefits: Energy saved

Atmospheric CO2 reduction

Air pollutants removed

Rainfall intercepted

Aesthetics & other

Research Process—Value Analysis (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—Value Analysis(Costs)Planting

Pruning

Removal and disposal

Pest and disease control

Irrigation

Infrastructure

Leaf litter cleanup

Liability

Administration

Research Process—Value Analysis(Net Benefits)

Convert resource units (kWh, lbs) to $

Annual Benefits:B = Energy + CO2 + AQ + Hydrology + property

value

Annual Costs:C = Plant + Trim + Removal + IPM + Irrigation +

Clean-Up + Sidewalk + Liability + Admin + Other

Net Benefits = B – C

Benefits/Costs ratio = B/C

Computer applicationAllows managers to evaluate current benefits, costs, and management needs.Input: - Sample inventory (3-5%)- Or existing inventory- Price adjustments, mgmt. costsOutput: - Graphs, charts, tablesBenefit: - Baseline data to more effectively manage the street tree resource

STRATUM: Information for Better Tree Management

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?