Question 1: Which trees are you most interested in?
- We want information on all of the trees in a specific area, such as the downtown, a historic district, or a park.
| || This is called a Partial Inventory. It provides a high level of information for the specific area, but can’t be used to assess the entire community.|
- We want a general picture of all of the street trees across the community, but time and money is limited.
| ||The Sample Inventory would be a good choice for this situation. By inventorying the trees in a random selection of locations (for instance, the trees along 6% of all of the streets in a community), you can make generalizations about the entire population without measuring every single tree, saving time and money. The downside is that hazardous trees or issues that are limited to areas that are not randomly selected will be missed, and any mistakes and inaccurate data will be enlarged when the data is used to represent the entire tree population. |
- We want to know about every public tree.
| ||This is a Complete Inventory. It takes the most time and money, but provides the complete picture and can be used to proactively manage your community trees.|
Question 2: What Data to Collect?
At a minimum, a tree inventory should include:
- Tree location (can be pinpoint in GIS, a street address, or a general location on a paper tally)
- Trunk Diameter (By size class such as 1"-6", to the nearest inch, or to the nearest 1/10th inch.)
- Species (Or at least genus, such as oak, maple, or ash)
- Overall Health/Condition (Such as good, fair, poor, dead)
Additional data that can help manage your trees:
Every piece of data that is collected adds to the time and cost of a tree inventory. Focus on the data that will answer the questions that are most important for your community right now.
- Maintenance needs (pruning, stake removal, mulching)
- Tree planting space (tree pit, tree lawn, etc.)
- Utilities present
Question 3: How often do you want the inventory to be redone?
- We want to do it once, and possibly do it again in the future
| ||A Snapshot inventory taken as a one-time tally provides useful information, but the data becomes obsolete as trees are planted, removed and/or increase in size. This necessitates the need to re-inventory the population periodically, which will also provide information as to how the population is changing over time.|
- We want to keep the inventory updated when trees are planted, removed, or receive maintenance.
| ||Some communities update their inventories on a Continuous basis. This requires special GIS or tree management software and allows staff to see the current status of any trees in real time. |