When people ask for help pruning their trees, many aren’t sure what to ask for. They know their trees need work but they don’t how to describe it. Tree service ads don’t help. They use terms such as trimming, cutting, topping, rounding, crowning, heading, shearing, lacing, sculpting, wind-sailing and the list goes on. The words attempt to describe pruning operations but they don’t explain what will be done. They leave tree owners scratching their heads and often disappointed with the results.
To help clear up the confusion, the American National Standards Institute (ANSI) developed a pruning standard called the ANSI A300. The A300, based on best management practices for tree health and safety, was created to help arborists write better pruning specifications.
The A300 recommends that proposals clearly state:
Pruning objectives: Such as structural improvement, size reduction, building clearance, etc.
Pruning types to be used: Such as crown cleaning, thinning, raising, reducing and restoring.
Minimum and maximum branch diameter for cuts: ½ inch, 2 inch, 6 inch, etc.
Maximum % of foliage removed: 5%, 10%, 25%, etc.
Tree pruning specifications are to an arborist what a set of blueprints is to a building contractor. They define the pruning outcomes that are planned and how they will be achieved. They tell what will and will not be done. They put the contractor, the tree owner and the crew all on the same page. And in the end, they clarify expectations and create a win-win for everyone.
A sample pruning specification using the ANSI A300 might look like this:
Tree: Mesquite (Prosopis velutina)
Location: Backyard north of garage
Pruning Objectives:
- Improve tree shape.
- Improve tree appearance.
- Improve tree safety.
- Clear branches away from roof.
- Elevate lowest branches hanging over sidewalk.
Pruning Types required to achieve the above objectives:
- Improve tree shape by Crown Reduction:
Reduce top and sides of tree 1 to 2 feet.
Min. branch diameter 2 inch. Max. branch diameter 3 inches.
- Improve tree appearance by Crown Cleaning:
Remove selected interior and exterior dead, broken and crossing branches.
Min. branch diameter 1 inch. Max. branch diameter 2 inches.
- Improve tree safety by Crown Thinning:
Remove selected interior branches with narrow angles of attachment.
Min. branch diameter 1 inch. Max. branch diameter 2 inches.
- Clear branches away from roof by Crown Thinning and Reduction:
Reduce branches 3 to 4 feet from roof and wall.
Min. branch diameter 1 inch. Max. branch diameter 2 inches.
- Special Instructions: Remove one 4-inch diameter branch over A/C unit by cutting it back to point of attachment at main trunk of tree. Branch is marked with orange tape.
When contracting for tree pruning services, request that your tree care provider define terms, establish clear objectives and describe the specific pruning types the workers will employ to achieve those objectives. If your service provider has difficulty describing the scope of work and measurable outcomes, it may be an indication they lack the knowledge and skill to prune trees correctly. And the last thing you want is for your trees to be damaged, sometimes beyond repair, by unacceptable pruning practices such as topping or lion’s tailing.
For a better experience, consider selecting a qualified company that provides clear pruning specifications based on the ANSI A300. You’ll be glad you did, and so will your trees!
From time to time, Water – Use It Wisely features guest bloggers who write about topics related to water and water conservation. The author of this blog post, John Eisenhower, is an ISA Certified Arborist and Owner of Integrity Tree Service in Phoenix, Arizona.