[The following text in this Tree Inventory Section was prepared by State Forester Bruce Webster.]
Bruce L. Webster, Staff Forester — Urban Forestry
P.O. Box 40627, Nashville, TN 37204
Tree Inventory Plan
The simplest form of inventory is a tree count. It is the quickest, easiest, cheapest inventory, and it can be done by anyone who can count. The results would be useful to someone who might want to know the number of trees on a given property or within a certain area, but a simple tree count has major limitations. Almost immediately questions such as “What kinds of trees are there?” or “How big are they?” are asked.
It is of the utmost importance to ask these types of questions before an inventory is conducted. A manager or owner must decide what information he or she needs and how that information will be used. Is knowing the tree species important? How much detail about tree location is required? Gathering information about trees is expensive and time consuming. Collecting more information than is needed is wasteful, but gathering too little information would necessitate redoing the inventory.
Why is an inventory of trees so important? There are several reasons. First, trees are a community resource. They produce shade, absorb air pollutants and mitigate storm water runoff. They have a direct, measurable positive economic benefit to a community. Second, trees provide psychological and aesthetic benefits. Third, trees are long lived, and as such, need to be considered part of the capital assets of the community. Fourth, trees need periodic maintenance. Because they are long lived, they cannot be ignored without adverse consequences to the community. And finally, they are large organisms and can create conflicts with and cause damage to homes, cars and other community assets.
Repeating the Inventory
Because trees are biological organisms, they create a dynamic environment. The forest or landscape is not static; it is constantly changing. Therefore, while data from the first inventory is used to guide development of the tree management, maintenance, or planting plan, the trees are changing, creating the need to repeat the inventory after a period of years.
The second inventory can be more valuable than the first because an inventory is a picture of the trees when data are collected. The second picture not only provides the basis for the revised management plan, it can be compared with the first and reveal the changes and trends that are occurring. To accurately capture these trends and changes, the same area must be inventoried the second time, whether or not it is the same plots or landscaped areas.