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

• Compost

• Hog Fuel

• Biochar

• Paper Products

• Cellulosic Ethanol

• Engineered Wood

Incre

ase

d P

rocess

ing

Tree Planting

Seed Planting & Sapling Growth

Sapling

Rough Cutting Sawmilling

Lumber Barriers,

Benches, etc. Engineered

Wood Production Pulping

Paper Products

Engineered Wood

Chipping or Grinding

Transport

Wood Chip Screening

Mixed Wood Chips

Manure or Food Waste

Sand

Overs

Composting Mulching

Hog Fuel

Landfill Waste

Wood Debris

Non-Tree Wood Waste

Cellulosic Ethanol

Fermentation

Debarking and Chipping

Storage Storage

Storage

Seed and Water

Contaminated Wood Chips†

Tree Growth

Tree Pruning

Tree Removal Immature

Tree Mature

Tree

Pruned Tree

Tree and Wood Debris

Firewood Transport

F/E

Other Applications

Storage

Other Applications

Storage

Storage

Storage

Transport

Pyrolysis

Bio-oil and Syngas

Biochar

Storage

Wood Chips Adhesives and

Binders

Storage

Fines Wood Chips

(Accepts)

Logs

Mulch Compost Storage

Other Applications Storage

Storage

Process Diagram for San Francisco Urban Tree Wood Re-Use

• Ovals indicate processes • Rectangles indicate materials • Yellow indicates relevant EOL wood products • Abbreviations:

GHG = greenhouse gas emissions P = pollution F/E = fuel and/or energy

• Dashed lines indicate processes and materials not recommended but shown for completeness

• Transport process indicates transport out of the city (transport within the city is not shown)

† Contaminated wood contains toxic chemicals (paint, waterproofing chemicals, chemicals to prevent rot, etc.) and is thus only suitable as hog fuel. This normally only occurs when non-tree wood waste is used.

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!