stratum: overview & process. session purpose i-tree stratum savvy community forest management
TRANSCRIPT
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?