Next> Guidelines for Developing and Evaluating Tree Ordinances http://www.isa-arbor.com/tree-ord/ PDF version Oct 31, 2001 Site Map Major funding for this web site is provided by the USDA Forest Service through the National Urban and Community Forestry Advisory Council and the International Society of Arboriculture. About this site How to use this site 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 <Previous | Next >. About this site This site provides a variety of tools and resources for citizens and local governments interested in developing, revising, or evaluating local tree ordinances. Rather than using a “model ordinance” approach, we describe how tree ordinance development can be integrated with an overall community tree management program. The site includes annotated examples of effective tree ordinance provisions used throughout the country. We also provide detailed descriptions of practical methods used to monitor community tree resources, tree management activities, and community attitudes. Support for the development and support of this site is provided by grants from the U.S.D.A. Forest Service through the National Urban and Community Forestry Advisory Council 1999 Challenge Cost-Share Grant Program, the International Society of Arboriculture, and ESRI, Inc., and in-kind contributions from: Phytosphere Research American Forests Society of Municipal Arborists (SMA) International City Management Association (ICMA) National Association of State Foresters (NASF) Alliance for Community Trees (ACT) California ReLeaf American Planning Association This content of this site was produced by Elizabeth A. Bernhardt and Tedmund J. Swiecki of Phytosphere Research, Vacaville, CA. It is based on the publication Guidelines for Developing and Evaluating Tree Ordinances (Bernhardt and Swiecki 1991). The original report was prepared for the California Department of Forestry and Fire Protection, Urban Forestry Program. A complete version of the original publication in Adobe Acrobat PDF format can be downloaded from the CalPoly Urban Forest Ecosystems Institute site. The purpose of this site is to provide practical information for communities dealing with tree ordinances and other urban forest management issues. We also hope to provide a means for sharing successful ordinance provisions and urban forest evaluation and monitoring methods used in cities and counties throughout the country. If you have material that you would like to submit for possible inclusion in the site, please e-mail Phytosphere Research. You may also contact us by phone (707-452-8735, 9-5 pm Pacific time) or mail (Phytosphere Research, 1027 Davis Street, Vacaville, CA 95687). How to use this site Whether a community is large or small, rural or urban, in a natural forest or in the desert, the basic process for developing a tree ordinance is the same. In each case, the community needs to determine what it has to work with and what it hopes to achieve. It must then formulate and execute plans to get what it wants, and finally, evaluate whether it is achieving its desired ends. The information in this web site is intended to guide you through this process. The process we recommend for developing or revising a tree ordinance is outlined in Part 1. Following the process in Part 1 will help you determine whether you actually need to develop or revise a tree ordinance. It also describes the importance of setting definite goals in the development of a tree ordinance. After reviewing the material in Part 1, you will be better able to effectively use the remaining sections of this site. Part 2 is a guide to drafting an ordinance. It shows how to select specific ordinance provisions to meet the tree management goals set by your community. Please note that this section does not present a "model" ordinance. Instead, it is a listing of provisions from various tree ordinances that can be used to help achieve specific goals. Individual ordinance provisions are presented and explained, and example text is provided. Using the input of local citizens, your community can select provisions and develop language that will yield an ordinance that is uniquely suited to its own needs and desires. How can you determine if your tree ordinance is working? Part 3 is a technical guide to methods which can be used to evaluate and monitor the effectiveness of ordinance provisions. Many of the evaluation methods described in this section may also be employed in the process of ordinance development described in Part 1. This site is designed to be used by either citizen groups or local governments. However, development of a tree ordinance will be most effective when both groups work together. Some communities have found that forming a task force is an excellent way of ensuring cooperation between groups with diverse interests. Phytosphere Research is an equal opportunity employer. <Previous | Next > Part 1. Planning for an ordinance More and more communities are beginning to recognize the very tangible benefits that trees provide in the urban environment. Healthy trees reduce air and noise pollution, provide energy-saving shade and cooling, furnish habitat for wildlife, enhance aesthetics and property values, and are an important contributor to community image, pride, and quality of life. Furthermore, many communities have realized that in order to protect and enhance their valuable tree resources, it is useful to view and manage their trees as a cohesive unit, the community or urban forest. Tree ordinances are among the tools used by communities striving to attain a healthy, vigorous, and well- managed community forest. By themselves, however, tree ordinances cannot assure that the trees in and around our communities will be improved or even maintained. Tree ordinances simply provide the authorization and standards for management activities. If these activities are not integrated into an overall management strategy, problems are likely to arise. Without an overall strategy, management will be haphazard, inefficient, and ineffective, and the community forest will suffer. This larger management view is commonly lacking when ordinances are developed. Local ordinances are often developed in response to public outcry over specific perceived problems. This "band-aid" approach frequently leads to ordinances that are not consistent with sound community forest management, and may in fact thwart good management efforts. For example, public outcry has led to the development of many ordinances designed to protect old "heritage" trees. Unfortunately, most of these same ordinances