BMP - Tree Inventories - 23

Imminent-failure has started or is most likely to occur in the near
future, even if there is no significant wind or increased load. This is
a rare occurrence for a risk assessor to encounter and may require
immediate action to protect people from harm.
Likelihood of impacting a target
Very low-the likelihood of the failed tree or tree part impacting the
specified target is remote.
Low-it is not likely that the failed tree or tree part will impact the target.
Medium-the failed tree or tree part is as likely to impact the target as not.
High-the failed tree or tree part will most likely impact the target.
Consequences of failure
Negligible-low-value property damage or disruption that can be
replaced or repaired, and does not involve personal injury
Minor-low-to-moderate value property damage, small disruptions to
traffic, or very minor injury
Significant-property damage of moderate-to-high value, considerable
disruption, or personal injury
Severe-serious personal injury or death, damage to high-value property, or disruption of important activities
Once these three components of risk are categorized, and a time frame for
the risk assessment identified, a risk rating can be determined. It is also
important to list the mitigation options to reduce risk. These options can
be prioritized by urgency. A re-inspection interval should be recommended
to monitor residual risk and changing conditions. Consideration should be
given to requiring tree risk assessment qualifications (such as ISA's Tree Risk
Assessment Qualification) for data collection personnel.

Maintenance

Primary maintenance needs should be included in every complete inventory.
The preferred nomenclature is based on the current version of the relevant
national pruning standard or ISA's Best Management Practices: Tree Pruning.
In the United States, the ANSI A300-Part 1: Pruning standard is the national
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BMP - Tree Inventories

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