By Dan Buckler, DNR Urban Forest Assessment Specialist, Milwaukee, Daniel.Buckler@wisconsin.gov or 608-445-4578

Tree inventories are foundational elements of sustainable urban forestry programs. You need to know what you have to best manage your trees. Because of the importance of these datasets, the Wisconsin DNR Urban Forestry program often funds inventories through their annual grants (open now through Oct. 2).

For the last few years, the program has required grant recipients that pursue inventories to collect a minimum baseline of attributes. These attributes ensure that the inventory is both useful to the organization and can be compiled into the Wisconsin Community Tree Map, a collection of tree inventories from around the state.

That baseline of attributes was recently updated. There were no attributes added to the previous version, but instead this update is clarifying the fields or preferred ways of recording data. If you receive a grant for an inventory or hope to get your existing inventory into the tree map, make sure it contains the baseline attributes. Basically, an inventory should track individual trees, be in a GIS format, and contain data pertaining to species, location, diameter, condition and the date or year at which trees are surveyed. Additionally, if a tree’s year of planting is known, please include that.

Though the above attributes are those that are required, most inventories contain many other data fields, all of which can shed light on the status of a site or tree, its management, or the surrounding environment. This document listing common tree inventory fields includes sample classes for many of those fields. Though the document shows fields often found in inventories, organizations should make sure that whatever data they are collecting are useful to them. Thoughtful planning is necessary before dedicating the time and expense of having people survey trees.

You can direct any questions about inventory attributes to Dan Buckler at Daniel.Buckler@wisconsin.gov. Questions about inventories more broadly can be directed to Dan or any of the DNR’s regional urban forestry coordinators.