Walking the grounds of the Redwood Sky Walk, Calif., performing a level 1 assessment, which includes visually scanning the trees to identify any significant issues.
LEVEL 1 A level 1 assessment provides an
indication of the general conditions of a forested site. This level of assessment is often used for power lines, checks of urban tree collections after a storm, or any other situation where a large number of trees must be evaluated. On an aerial adventure course, a level 1 as- sessment is appropriate for identifying possible tree issues within range of the course trees and elements. What? A level 1 is a visual scan of the trees surrounding the course. An arbor- ist will take a short look at your trees, usually from one aspect, and identify significant issues such as the develop - ment of leans, broken branches target- ing the course, or stem decays. Based on the issues identified, the assessor will make recommendations to the operator for immediate management, monitoring, or further assessment. When? This level of assessment should be done by an arborist prior to building a course, as a yearly inspection, and after major weather events. In addi- tion, the arborist can train your staff to conduct internal level 1 assessments, allowing your team to identify issues that may need an arborist’s attention in between regular inspections. LEVEL 2 Also called a basic assessment, a level 2 assessment allows an arborist to spend some time with each tree. Using visual assessment and basic tools, a level 2 as- sessment will uncover many facts about the way a tree is growing and identify conditions of concern visible from the ground or with minimal excavation around the root flare. What? Most arborists will bring some of the following tools when carrying out a level 2 assessment: a diameter tape, a laser hypsometer and azimuth, a com- pass, a sounding mallet, a soil probe, a trowel or other digging tools, a mattock, chisels, hand pruners, a magnifying glass, binoculars, and a camera. These tools allow the arborist to evaluate trees with more depth than the purely visual level 1 assessment.
A lthough trees pose a generally very low risk to people and facili- ties, stuff happens. Aerial adventure operators need to be proactive—not reactive—about tree health in order to minimize risk. This requires actively paying attention to your trees and having them regularly inspected and assessed by a qualified arborist.
Thinking through potential tree threats allows managers to make adjustments, such as tree pruning and cabling or moving or reinforcing facilities, to reduce risk. Staff doing daily course inspections should be trained to observe trees at a basic level and to report any changes to their supervisor (See “Reading the Trees,” API Summer 2021) . Inspections by a qualified arborist should also be a component of the management plan for every site where trees are present. Arborist inspections should happen at least once per year. For seasonal oper- ations, inspections are recommended after closing to plan off-season main - tenance and before opening to ensure everything made it through the winter and is safe to open for business. THREE LEVELS OF ASSESSMENT When professional arborists inspect trees, there are three levels of assess- ment that can be considered, pro- gressing from simple to complex. All three levels require knowledge of how trees grow within their environment, of the characteristics of individual tree species, and of the impact of human activities near trees. Not every arborist
has this skill set, so it is important to ask about your arborist’s qualifications and the types of assessments they regularly perform. Here, we’ll outline the three levels of tree assessment to help you gain an un- derstanding of what each involves and so you can better determine if an ar- borist is qualified. With this knowledge, you can ask arborists simple questions like, “What level of assessment do you recommend for these trees?” or “What types of tree assessment have you done on adventure courses in the past?” and understand and evaluate the responses. Caution: Don’t confuse a free bid for tree work by a commercial arborist with an assessment conducted by an experienced consulting arborist. Free bids can lead to recommendations for unnecessary tree management or lack vital information about a serious tree condition, for example. An assessment by a consulting arborist, on the other hand, will be more thorough. Consulting arborists typically charge by the hour and may also charge fees for the use of testing equipment or samples sent out for lab analysis.
A TRAQ qualified arborist (Arborist Qual- ifications sidebar, next page) will gener-
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