Brugia Malayi - Clark Science Center - Smith College

Tree Hazard Ratings at the Smith College Arboretum
Jennifer Rioux
The campus of Smith College is made beautiful by trees of all sizes. The same trees that beautify our campus can become
significant hazards when in declining health. It was recommended by a lawyer that the botanic garden set up a system to ensure
every tree on campus be thoroughly inspected on a regular basis to protect against accidents such as a limb falling on a pedestrian
or a car. Systems for inspection have been created in the past but none fully met the needs of the botanic garden. The new rating
system used was based off of tree hazard-rating methods from other arboretums and past botanic garden intern work. It was
determined that rating trees using the USDA community tree risk evaluation form would be most useful to the staff of the botanic
garden. This system rates the trees on a three to twelve point scale through four sections. The sections are probability of failure,
size of defective parts, probability of target, and other risk factors. The ratings of these sections add up to a total score indicating
the level of danger the tree poses. Thirty trees were rated to test the system this summer. The trees chosen for the sample were
some of the least healthy trees on campus. Their ratings ranged from five to twelve. The tree with the terrifying rating of twelve
will be removed in the near future. It is completely hollow from decay. Once rated the trees were mapped using GIS software and
can be easily viewed on a campus map. This map allows the botanic garden staff to visually see which trees need attention and
when they need it most. This project is ongoing and will become even more useful as trees are added to the map. (Supported by
the Schultz Foundation)
Advisor: Michael Marcotrigiano
References:
Albers, J. S., Pokorny, J. D., & Johnson, G. (2003). Defective trees: Risk assessment guidelines. Urban tree risk management, 10(8), 1-9.
Davison, E., & Brandt, B. (2009). Campus tree care plan. University of Arizona Campus Arboretum.
Jonnes, J. (2011). What is a tree worth? The Wilson Quarterly.
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