Q&A about the Urban Tree Health Method
Photos by Jerry Bond
This 800-yr-old dance linden (Tilia platyphyllos) in Germany has lost its structural stability and would fall apart without the scaffolding.
But its biological health continues to be very good and it renders good services to the surrounding community.
City Trees interviews Jerry Bond
(Urban Forest Analytics LLC), urban forestry consultant
and author of the 2012 book, Urban Tree Health. We
focus on understanding the overall concepts and procedures of his method rather than its scientific and
technical details.
the mechanical aspects of a living tree. But those two
aspects are really very different, rather like the polyp
and the coral reef it creates, and should be evaluated
separately to avoid confusion. After all, we routinely
see healthy trees fail, and stable trees die.
CT: What is the basic approach of your method?
CT: How do you define "tree health"?
It strives for two great objectives: to be practical, so it
Tree health refers to the capacity of a tree 1) to resist can be used in everyday situations, and to be precise,
the disruption of the system (soil, climate, pests, so that its results are repeatable from one evaluation
etc.) it inhabits and 2) to render services to the sur- to the next.
rounding human community. This definition combines
In order to achieve those objectives, the method
ecological research with research about the environexcludes structural stability from its attention. And
mental and social benefits that are so important for
it separates observation from interpretation as rigorurban trees.
ously as possible, so that field data collection can
I use the word "health" rather than "condition," be reasonably insulated from factors such as differbecause condition includes both the biological and ences of knowledge, lack of experience, or bias.
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City Trees
