One of the main jobs of the arborist is to give trees a purpose. And trees do serve many purposes as we know, both culturally and from an ecosystem perspective. They mark boundaries and birthdays. Trees are the backdrop to which life unfolds. Especially the life of the arborist, the sapsucker and the brown creeper. As many arborists know, trees have value. And value can be assigned through observation, and increased through proper investment.

Trees have even more value when they are well documented, and well maintained. And because maintenance should begin with thorough inspection, tree inspection is a great place to begin when assigning and designing tree value.

A powerful tool for inspecting trees is the condition rating concept from the Council of Tree and Landscape Appraisers Guide for Plant Appraisal (9th ed.). In order to give trees a condition rating, there are five factors to consider: Roots, Trunk, Scaffold Branches, Small Branches and Twigs, and Foliage and Buds. (Table 4.3, 34) Each of the five factors is scored using a specific, 4-point system. For the first three factors (roots, trunk and scaffold branches) the tree is scored in two categories: health and structure. Whereas the last two factors (Small branches and twigs; and foliage and/or buds) are scored only on health. The conceptual worksheet looks similar to this:

Roots: ____+____=____

Trunk: ____+____=____

Scaffold Branches: ____+____=____

Small branches and twigs: ____

Foliage and/or Buds: ____

The point system is 4-1. Here is the breakdown:

No apparent problems: 4

Minor problems: 3

Major problems: 2

Extreme problems: 1

Once you’ve scored the tree you’re inspecting, you divide that total by 32 (which is the total possible points) and multiply by 100 for your condition rating.

I believe that this condition rating tool is a powerful one for several reasons. It can be used on many fronts. If we borrow terminology from the risk and assessment vocabulary, we can put the condition rating use to work with either basic level one ssessments, level two assessments or level three advanced assessments. We can apply different tools available to arrive at all or any factors of a condition rating such as climbing gear and crown access tools for aerial inspections, air-spades for extensive root inspection or resistographs for more thorough trunk inspections. Although the condition rating idea comes from the plant appraisal business, it is a concept that can be reconciled with other areas of arboriculture when it comes to not only documenting inspections, but also in writing specifications and prioritizing work. The condition rating provides a great context for tree inspection documentation.

That is to say, the higher condition rating of a tree, the less priority of maintenance it would require, in theory, of course. A score of 56% requires more attention than a score of 95% in any classroom. It’s a great measure of where trees need to improve. And what’s better is that it clearly illustrates that for clients in a numeric way. And to be quite honest, clients and tree owners love percentages, as do arborists. But what is it that tree owners love even more than percentages? A return on their investment. Another brilliant role the condition rating can play is to illustrate for tree owners how their tree conditions increase with the proper maintenance and attention.

Let’s look to the scoring system of the condition rating worksheet when considering a return on maintenance. Extreme problems can be mitigated to minor problems or even no apparent problems, which is a net gain of 3 points in only one category with regards to the condition rating scoring system. That net gain in scoring could be reflective of the process of a cable or brace installation, pruning a dead scaffold limb from the crown or removing a girdling root from the trunk flare of the tree. So then, the condition rating also provides a map of improvement for tree maintenance schedules to build off of. Properly applied maintenance dosages can improve the condition rating of the tree. The percentages will increase. Tree condition can change, and with that change, tree value will increase. These types of maintenance engagements create a story for the tree from which value can be built. It is the same way wealth is built: through vision, planning, observation and adjustment. It’s smart arboriculture.

The condition rating is a key variable in the cost method of the tree appraisal process. Documenting the condition ratings of your trees as they grow and maintenance progresses can also make it a key variable in your clients deciding to invest more in you and their trees. A condition rating that is increasing is not only a healthy tree, it is a more valuable tree. As a tool, the condition rating as a concept can be used to illustrate why maintenance is important in very detailed ways, on very specific areas of very specific trees. The condition rating can quantify the value of maintenance and how it affects the overall value of trees. Improve condition ratings requires active arboriculture. The condition rating is a great tool for all arborists and all tree owners.