Urban & Community Tree Inventories
Courtesy: North Carolina Division of Forest Resources
To effectively manage community trees, a tree inventory is a valuable tool and is essential in developing a management plan. It is particularly useful in mitigating liability should a tree cause damage or injury. Managing tree care, planting, pruning and removals in a cost-effective way can also be improved by a tree inventory. A tree inventory must be dynamic since trees and their environments are dynamic. Ways to approach a tree inventory and methods of data collection are described below:
Paper and Volunteers - the simplest and most inexpensive method of data collection is to have volunteers record basic tree information with paper and pen. Data collected can then be entered into a spreadsheet. While this is not a method conducive to true forest management, it can be a good start for small communities that need an idea of what is actually happening in their urban forest. Volunteers should not be used for any inventory collected for management purposes, since quality and consistency are not always reliable.
PDAs (handheld computers) and Contractors - Using a PDA, inventory information can be collected and uploaded to a PC. PDAs are also a quick and efficient way to update tree information on-site. Information should be collected by community or contract employees to ensure consistency. While requiring some expense, this is a relatively inexpensive way to initiate a management program.
Proprietary Software and Consultants - Computer programs designed specifically for tree inventory data collection are a valuable tool for creating detailed management plans. Usually, data is collected by consultants who work for the company providing the programs. At a minimum, tree management options in the software allow tracking service requests, tree maintenance activities and updating a tree's attributes. Programs are available with or without GIS (Geographic Information System) and GPS (Global Positioning System) technologies. However, mapping specific tree locations is not generally useful for most communities unless a GIS is already in place (with data for surrounding streets, utilities etc.). The main exception to this is the mapping of parks and large landscapes (such as colleges and large facilities). When selecting a consultant check references, as program ease-of-use and good technical support/training is as important as price. Most companies provide technical support for a period of time and updates to the software. When getting a price for data collection a community should have a reasonable projection of the number of miles to cover and average number of trees per mile, for an inventory estimate cost. A summary report of the survey results and their significance should also be part of any complete inventory.
How Much Information Do You Need?
A full inventory of all trees on community property can be collected, or only street trees, or only non-street trees, depending on the needs of the community. If the community budget does not initially allow for a full inventory, a program can still be started by collecting only hazard tree, and/or boundary tree, and/or line-of-sight tree (to determine visibility at intersections) information. Managing for liability and safety are good starts in establishing a complete urban forestry program.
Standard information typically collected for each tree includes species, diameter, condition or maintenance needs, location (address or GPS information) and utility and/or sidewalk conflicts. Available planting space at each location is useful to collect for planning future urban forest needs.
Inventory Software & Services
Web sites for software and data collection are listed below. Before purchasing software, ask for a "test-drive" to make sure it will fit the community's needs and will be user-friendly. Listing does not constitute endorsement by NCDFR, NCDENR or the state of North Carolina.
Software Sales and Data Collection
Guidelines for Developing and Evaluating Tree Ordinances provides a variety of tools and resources for citizens and local governments interested in developing, revising, or evaluating local tree ordinances.