Defining Reasonable Care

by Mark Duntemann
Natural Path Urban Forestry Consultants
July, 1997

There was a heightened public awareness of the danger of structurally unstable trees in public areas following the deaths of four children in Queens, New York this past March. Their deaths were the result of a large diameter silver maple falling on their school bus during a torrential storm. As a result of this tragedy, many communities across the country probably took action to remove trees that were perceived as hazardous from their streets and parks. Rather than reacting reflexively to a tragedy, communities would be better served if they implemented a sound, long-range risk management policy.

Vegetation managers are simply reacting to an immediate crisis when they remove hazard trees strictly on an individual basis. The management of a large number of trees requires that management decisions be based on the collective health of the urban forest, not on individual trees. A risk management program establishes management strategies for continuously evaluating and monitoring trees that pose a risk, and defining what level of care is reasonable for a community.

Reasonable care in respect to high-risk trees should be defined by each community according to its resources. However, defining what is reasonable is not always in the hands of the municipality or vegetation manager. For instance, in several court cases for which I have served as expert witness, it has been an attorney that defined the level of care that a community should demonstrate. The city or parks department rarely has an established policy that defines a reasonable level of care for their agency, and as a result, is subject to the attorney's definition. I pose the question; who is better suited to determine what level of care is reasonable for your community? The answer is, you are!!!

There can be no universal definition of reasonable care for a community's risk trees since the resources available to each community vary. In other words, the level of care given to the trees in one community may not be a reasonable level for another. I have highlighted four steps you can follow to help you define the level of care that is right for your community. These steps are: assess the dynamics of your tree population, define the resources available to manage your tree population, create a risk management policy statement, and develop and implement a risk-reduction plan.

ASSESS YOUR TREE POPULATION

A key element in developing a reasonable risk management policy is identifying the extent of the high-risk features in your tree population. A tree inventory is the best tool for identifying these features. Risk features may not pose a problem individually, but the risk increases when combinations of the following four features occur:

• Problem Species

  Invariably, there are species in each community that are more problematic than others. Some characteristics of problem species are: a high storm damage rate, enhanced structural decay, repetitive dieback, and a short life-span. By identifying the problem species and their quantity in your population, you are narrowing your focus to a manageable number of trees to monitor; the ones with the highest potential for problems.

• Diameter Classes of Problem Species

  It is important to look at the diameter distribution of your individual problem species. Large- diameter, poor-quality species will be more problematic than small-diameter, poor-quality species. The most immediate attention should be given to trees in the larger-diameter classes, however, a progressive risk-reduction policy will incorporate the gradual removal of small diameter problem species as well.
  
  The smaller-diameter trees of problem species are not immediate risks to your community but they have a high potential to be so in the future. The removal of problem species when they are young is less of an expense and also allows you to replace these species with more appropriate species at an earlier time.

• Trees with Structural Defects

  Identify trees in your population that have structural defects such as basal decay, trunk cavities, or extensive root rot. These trees have a high potential for being risks to the community and should be monitored more closely. Structural defects are not typically species specific, but a problem species you have identified in conjunction with a structural defect increases the risk factor of that particular tree.

• Distribution of Tree Population By Condition

  Assess your tree population by condition classes. Trees in the poorest condition class are trees that are the most problematic in the short term.

By evaluating the unique interrelationship of these four criteria within your tree population you can begin to develop a template for an action plan.

EVALUATE YOUR MANAGEMENT RESOURCES

Once you narrow your focus to a refined list of trees, you can assess your budget and labor force to design a risk management program that is suited to your community.

• Assess Personnel Activities

  Define how your personnel is used throughout the year. Use a weekly-based time scale to review the activities of your work crews or individual staff. Look for activities that can be modified to allow some time for hazard tree monitoring. There are certain times during the year that risk trees can be monitored without conflicting with regular activities. For instance, if a community usually reserves two to three weeks in November to remove trees, the appropriate time to monitor for hazard trees is immediately before removals begin.

  In addition, there are certain activities such as stump grinding or leaf pickup that may be more time and cost effective to contract out, which would free up your staff to conduct risk assessments.

• Review Your Work Schedule

  Calculate the minimum time available for your staff to conduct assessments and removals of hazard trees. It is easy to argue that a community should monitor trees and conduct removals every day. Isn't this the only way to guarantee reasonable care? No. Every facet of a progressive forestry program incorporates risk management. A cyclic pruning program improves health, facilitates monitoring, and reduces risk. Plantings allow for the replacement of poor-quality species with more appropriate ones. Service request responses allow you to effectively use the public to pinpoint problem trees. I strongly recommend that a community schedule inspections in such a way as to not compromise other key elements of their program.
  

• Assess Monetary Resources

  Assess the financial resources traditionally available to conduct risk assessments and removals.

  If you have contracted out removals, assess the amount of money that is spent each year in removal contracts and the total number of trees that are removed. Likewise, if your in-house crew performs all of the removals, you should assess the amount of time that is devoted to this activity as well as the total number of trees they remove. It may be possible to modify your budget and personnel time to allow for a slight increase in risk management tasks.

By evaluating your management resources you will be able to define the maximum amount of time available to conduct risk assessments and removals as well as who will be responsible for carrying out the work. You may find that you have no additional time or money available to conduct assessments, but at least you can document this conclusion.

CREATE A RISK POLICY STATEMENT

Once you determine the level of care that is manageable for your community, the next step is to develop a clear policy statement. You should review your policy on an annual basis to make sure the level of care remains appropriate. An established risk reduction policy is the strongest defense a community has in court in respect to hazard trees.

The risk reduction policy statement should include the following:

• State your Agency's understanding of its responsibility to maintain a safe public area.
• Identify the manager of the risk reduction program.
• List any general constraints on managing hazard trees such as financial or personnel.

Refer to my article "The Politics of Risk" for an example of a risk management policy statement.

IMPLEMENT A RISK MANAGEMENT STRATEGY

Once a risk management policy is in place, you should implement a risk management strategy in your community. The portion of the tree population with the highest probability of risk should be the target of the management strategy you design. I have listed an example of an action strategy for a specific problem species.

To meet your risk reduction goal in the ten year period, your initial action strategies should focus on the removal of high-risk box elders as highlighted by the first two actions listed. Your strategy in the latter half of the ten year period should incorporate the removal of the remaining lower-risk box elders, as highlighted by the last two actions listed. While several communities may have the same overall goal for risk reduction, the defined objectives and associated actions will, and should, vary greatly between each community.

The overall focus of any risk management program should be identifying the features of the tree population with the highest potential of failure, and then concentrating the available management resources on mitigating those features within an appropriate timeline. By establishing a long-term risk reduction program for your community, you create a defensible and definable level of care for your community.

 

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