Table Of Content

SAN FRAN3ISCO PUBLIC LIBRARY 3 1223 07389 4066 5/S DOCUMENTS DEPT. MAY - 4 2006 FranciscoPublicLibrary SAN FRANCISCO PUBLIC LIBRARY Scvernment Information Center Jan Francisco Public Library Larkin Street. 5fr Floor inFrancisco, CA b-»i02 FERENCE BOOK to be taken from the Library 977 lest Research c I DOCUMENTS DEPT. MAY - 4 2006 SAN FRANCISCO PUBLIC LISRARY 1 Areas of Research: InvestmentValue Mission Statement | Energy Conservation We conduct research that demonstrates new ways in which trees add value to your community, converting results into financial terms Air Quality to assist you in stimulating more investment in trees. •*w(USm>on**.! ..I J..,.IH Water Quality LISDA isanc»)»wlopportunityproviderandemployer. Firewise Landscapes City of San Francisco, California Street Tree Resource Analysis Scott E. Maco, E. Gregory McPherson, James R. Simpson, Paula J. Peper, Qingfu Xiao Acknowledgments We are indebted to the following people in the City of San Francisco who provided assistance and support with various aspects ofthis project: Milton Marks and Doug Wildman (FUF); Paul Sacamano, Tony Wolcott, and Carrie Durkee (DPW). Without the help and diligence ofFUF staff(Ellyn Shea, Bill Hart, Karla Nagy, Chris Buck, and Jeanette Hill), volunteers (Geoffrey Smith, Kelly Palomera, Maureen Kelly, Karen Noll, Cesar Viana, Pam Lovell, Jim Hickey, Hattie Mullaly, Johno Campos, Dick Olsen, James McCormick, April Ringler, and Tai Truong), and Forest Service employees (Tommy Mouton, Mary Street, and Ara Erickson), this work would have been impracticable. Thankyou. City of San Francisco, California Street Tree Resource Analysis Scott E. Maco, E. Gregory McPherson, James R. Simpson, Paula J. Peper, Qingfu Xiao Table of Contents Acknowledgments Executive Summary v — ChapterOne Introduction — ChapterTwo Methodology And Procedures '. Growth Modeling '. & Identifying Calculating Benefits '. Energy Savings • Electricity And Natural Gas Methodology < Atmospheric Carbon Dioxide Reduction SequesteredAnd ReleasedCo Methodology 2 Avoided Co Emissions Methodology 2 Improving AirQuality 1 Avoided Emissions Methodology h Deposition And Interception Methodology li BVOC Emissions Methodology li Reducing Stormwater RunoffAnd Hydrology 1< StormwaterMethodology 1 & Aesthetics OtherBenefits 1 Property Value And OtherBenefits Methodology l: Estimating Magnitude OfBenefits l; CategorizingTrees By DBH Class 1 Applying Benefit Resource Units To Each Tree 1! ii 1 Matching Significant Species With Modeled Species 13 GroupingRemaining"Other" Trees By Type 14 Calculating Costs 14 Public StreetTrees 14 Private StreetTrees 14 CalculatingNetBenefitsAnd Benefit-CostRatio 15 NetBenefitsAndCosts Methodology 15 Assessing Structure 16 InventoryProtocols 17 Calculating Structural Attributes 17 — ChapterThree SanFrancisco's StreetTreeResource 19 TreeNumbers 19 SpeciesRichness 19 SpeciesComposition 20 Diversity 20 SpeciesImportance 2 StreetTrees PerCapita 22 Stocking Level 22 Age Structure 22 Tree Condition 24 Location & Land-Use 25 StreetTreeConflicts 25 SidewalkHeave 25 OverheadUtility Lines& Topping 26 Visibility 27 MaintenanceNeeds 27 General 27 Safety 28 Removals 28 iii — ChapterFour CostsOfManaging San Francisco's StreetTrees 30 Fiscal Year2001-2002 ProgramExpenditures 30 Costs OfManaging Public Trees 30 Costs OfManaging Private Trees 30 — ChapterFive Benefits OfSanFrancisco Street Trees 32 Introduction 32 Electricity AndNatural Gas Results 32 Atmospheric Carbon Dioxide Reductions 32 AirQuality Improvement 33 NetAvoided EmissionsResult 33 Deposition And Interception Result 33 StormwaterRunoffReductions 34 Property Values AndOtherBenefits 35 Total AnnualNetBenefits And Benefit-CostRatio (BCR) 35 — Chapter Six Management Implications 40 Resource Complexity 40 Resource Extent 42 & Pruning Maintenance 42 Controlling Costs 43 — Chapter Seven Conclusion 44 — ChapterEight References 45 Appendix A: Rapid Sample Field Inventory DataCollection Protocols 48 AppendixB: Resident/OwnerStreetTree Care Survey 52 AppendixC: Species Code Reference List 54 Appendix D: Total Citywide and District StreetTreeNumbers 58 Citywide 59 iv District 1 60 District2 61 District3 62 District4 63 District5 64 District6 65 District7 66 District8 67 District9 68 District 10A 69 District 10B 70 District 11 71 V Executive Summary City of San Francisco, California Street Tree Resource Analysis Scott E. Maco1 E. Gregory McPherson1 James R. Simpson1 Paula J. Peper1 , , , , Qingfu Xiao2 Street trees in San Francisco are comprised of two (18,234 ±2,779) ofthe total, while privately distinct populations, those managed by the city's cared for trees comprised the remaining Department of Public Works (DPW) and those 81.5%(80,301 ±9,634). managed by private property owners with or without the help ofSan Francisco's urban forestry nonprofit, • While San Francisco is on par with the Friendsofthe Urban Forest(FUF). Thesetwo entities statewide average of 104 trees per street believe that the public's investment in stewardship of mile, there are many opportunities to San Francisco's urban forest produces benefits that increase the resource extent. Approximately outweigh the costs to the community. Hence, the 127,500 site—s—56% of all street tree- primary question that this study asks is whether the planting sites were unplanted, ranging accrued benefits from San Francisco's street trees from 28%to 74% amongdistricts. justifythe annualexpenditures? • Citywide, the resource represented 115 This analysis combines results ofa citywide sample differenttree species and diversity was high. inventory with benefit-cost modeling data to produce However, several districts were dominated fourtypes ofinformation (Maco 2003): by few species and lack ofdiversity should be ofconcern to managers. 1. Resource structure (species composition, diversity, age distribution, condition, etc.) • Having the most numbers, leaf area, and canopy cover, Victorian box and London 2. Resource function (magnitude of plane were found to be the two most environmental and aesthetic benefits) important streettrees in San Francisco. 3. Resource value (dollar value of benefits • Age distribution varied by district, but realized) citywide the street tree population was immature, lacking adequate numbers of 4. Resource management needs (sustainability, functionally maturetrees. pruning, planting, andconflict mitigation) Resource Function and Value Resource Structure • Based on the FUF inventoried sample of • Because of San Francisco's moderate summer weather, potential energy savings 2,625 trees, there were an estimated 98,534 from trees are lower than those that would (±9,677) street trees in San Francisco. Publicly managedtrees accounted for 18.5% be found in wanner inland locations. Electricity and natural gas saved annually from both shading and climate effects MWh totaled 651 and 1,646 Mbtu, 'CenterforUrbanForestResearch respectively, for a total retail savings of USDA ForestService, PacificSouthwestResearchStation $85,742 ($0.87/tree). c/o Dept.ofEnvironmental Horticulture UniversityofCalifornia Davis,CA 95616-8587 • Citywide, public trees sequestered 611 tons of the greenhouse gas carbon dioxide. The departmentofLand,Air,andWaterResources same trees offset an additional 71 tons UniversityofCalifornia,Davis,CA through reductions in energy plant emissions. Private trees had an annual net vi