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Guidelines for Developing and Evaluating Tree Ordinances

Citation for this website:

Swiecki, T. J., Bernhardt, E. A. Guidelines for Developing and Evaluating Tree Ordinances. Phytosphere Research, Vacaville, CA. http://phytosphere.com/treeord/index.htm. Accessed: (Access date)

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Part 1. Planning for an ordinance

• Types of ordinances
• Effectiveness of existing ordinances
• Developing a community forest management strategy
  • How to develop a management strategy
    • What do you have?
      • Step A. Assess the tree resource
      • Step B. Review tree management practices
    • What do you want?
      • Step C. Identify needs
      • Step D. Establish goals
    • How do you get what you want?
      • Step E. Select tools and formulate the management strategy
      • Step F. Implement the management strategy
    • Are you getting what you want?
      • Step G. Evaluate and revise
        
• Goals for community forest programs

Part 2. Drafting an ordinance

• Basic ordinance provisions
• Ordinance provisions for specific goals
• View or solar access ordinance provisions

Part 3. Evaluating the urban forest and ordinance performance

Methods for evaluating tree ordinances and the urban forest ecosystem

• Sampling from populations
  • Statistical bias
  • Random sampling and random numbers
  • Stratified sampling
  • Sample size
  • Links to sample size calculators
• Photogrammetry and remote sensing techniques
  • Uses
  • Materials needed
  • Notes
  • Sampling considerations for photogrammetry
  • Estimating tree canopy cover from aerial images
    • Visual (ocular) method for estimating canopy cover
    • Dot grid method of canopy estimation
      • Determining sample size for dot grid estimates
      • Evaluation example: Overall canopy estimates in permanent plots
    • Line intercept or transect method
    • Digital image analysis methods
      • Comparison of image analysis and dot grids for calculating tree canopy cover
  • Other resources
  
  
• Ground survey
  • Uses
  • Materials needed
  • Notes
  • Sampling considerations for ground surveys
  • The windshield survey
    • Evaluation example: Windshield survey for tree topping incidence
  • The foot survey
    • Tree size
      • Evaluation example: Measurement of canopy cover at the edge of pavement
      • Evaluation example: Evaluating parking lot shading
      • Simplified guide to measuring DBH
    • Tree condition/health
    • Proximity to infrastructure and hardscape damage
    • Rating scales
      
• Photo points
  • Uses
  • Materials needed
  • Notes
  • Ground level photo point
  • Aerial photo points
  
  
• Record keeping and analysis
  • Uses
  • Materials needed
  • Notes
  • Geographic Information Systems (GIS)
    • Evaluation example: Creating a forest/tree GIS
    • Evaluation example: CITYgreen software for ArcView GIS
  • Tree inventory systems
    • Additional resources
    • Evaluation example: Street tree inventory as part of a citywide GIS
    • Evaluation example: Street tree management
  • Inventorying regulated private trees
• Public polling
  • Uses
  • Materials needed
  • Notes
  • Interviews
  • Self-completed questionnaires
  • Survey design considerations
  • Sampling considerations for public polling
  • Evaluation example: Homeowner attitudes toward trees

Special Topics:

Defining special trees: heritage, historic, and landmark trees

Definitions: Tree banks and tree banking

Concepts: Mitigating for tree loss 

Literature Cited

Additional References

• General
• Dot grid estimation
• Public Polling