San Francisco Urban Forest Wood Re-Use Study
Presidio Graduate School Jonathan Dirrenberger Cheryl Dorsey Ryan Miller Sonja O’Claire
Agenda • Presidio Team • Project Scope • Methodology • Case Studies • Current State of Re-Use • Stakeholders • EOL Wood Products • Recommendations • Barriers to Implementation
Presidio Team
• Presidio Graduate School Sustainable Management MBA candidates • Experiential learning project for Operations and Production course • Study produced for SF Planning Department
Project Scope
• Current wood waste processes • Street Trees (DPW) • Park Trees (RPD) • Case studies • Evaluate EOL processes • Make recommendations for a future wood re-use program
Methodology
• Stakeholder meetings • Facility tours • Phone interviews • Demand forecast • Value analysis
Case Studies
• Sacramento, CA • Olympia, WA • Cincinnati, OH
Current State of Re-Use • DPW (Street Trees) • Hauls to Recology • RPD (Park Trees) • Chips, mulch and composts all tree waste on-site • Some logs used in parks • 100% re-use rate • Lumber is not a current end product • Estimated 10-20% of removed trees are of lumber quality
Stakeholders Urban Tree EOL Wood Products
• Logs • Lumber • Wood Chips • Mulch
IncreasedProcessing • Compost • Hog Fuel • Biochar • Paper Products • Cellulosic Ethanol • Engineered Wood
Immature Mature Debarking and Tree Growth Tree Removal Logs Storage Transport Tree Tree Chipping
Storage Storage
Pruned Adhesives and Tree Pruning Sawmilling Rough Cutting Wood Chips Tree Binders
Tree and Wood Barriers, Engineered Transport Storage Lumber Wood Debris Firewood Pyrolysis Fermentation Pulping Debris Benches, etc. Wood Production
Landfill Chipping or Non-Tree Bio-oil and Cellulosic Paper Engineered F/E Biochar Waste Grinding Wood Waste Syngas Ethanol Products Wood
Mixed Contaminated Storage Transport Wood Chips Wood Chips†
Wood Chip Overs Hog Fuel Screening Process Diagram for San Francisco
Manure or Wood Chips Sand Fines Storage Other Applications Food Waste (Accepts) Urban Tree Wood Re-Use
Storage Storage • Ovals indicate processes • Rectangles indicate materials Composting Mulching • Yellow indicates relevant EOL wood products • Abbreviations: GHG = greenhouse gas emissions
Seed and P = pollution Other Applications Storage Compost Mulch Storage Other Applications Water F/E = fuel and/or energy
Storage Storage • Dashed lines indicate processes and materials not recommended but shown for completeness Seed Planting & • Transport process indicates transport out of the Sapling Growth city (transport within the city is not shown) † Contaminated wood contains toxic chemicals (paint, waterproofing chemicals, chemicals to Sapling prevent rot, etc.) and is thus only suitable as hog fuel. This normally only occurs when non-tree wood waste is used. Tree Planting Defining Value of EOL Wood • Minimize GHG emissions and pollution • Minimize landfill • Keep local • Reduce costs • Raise awareness • Optional: obtain revenue
Lee, C., Erickson, P., Lazarus, M., & Smith, G. (2010). Greenhouse Gas and Air Pollutant Emissions of Alternatives for Woody Biomass Residues, Final Draft Version 2.0. Stockholm Environment Institute Lee, C., Erickson, P., Lazarus, M., & Smith, G. (2010). Greenhouse Gas and Air Pollutant Emissions of Alternatives for Woody Biomass Residues, Final Draft Version 2.0. Stockholm Environment Institute Best Options • Priority • Lumber & Logs • ~10-20% of removed trees • Secondary • Wood chips, mulch, and compost • ~70-80% of removed trees • Last resort • Hog fuel • ~10% of removed trees • Future • Biochar • More research needed
Demand & Financial Value - 2014 Demand & Financial Value - 2034 Key Recommendations 1) DPW process and store wood chips, mulch, and compost 2) The City develop program to harvest lumber • Short term: pilot for rough sawn program • Long term: rough and finished lumber 3) DPW & RPD share wood processing resources
Secondary Recommendations
A. Improve data collection
B. Pre-empt possible public disapproval Barriers to Implementation
• Funding
• Legal & policy barriers
• Public opinion Thank you!