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ANSI A300 Pruning Standards
The American national
Standard for tree pruning is ANSI A300. It's development process
was approved by the American Standards Institute. The A300
standard has been drafted to address pruning specifications across
all geographic areas. Knowledge of the growth habits of certain
tree species within a given environment may alter how the
recommendations of A300 are interpreted.
With the American National Standard for
pruning, ANSI300, specifications can be written in a virtual
infinite number of combinations. The following information is
designed to help you understand exactly what will be accomplished
in a pruning operation.
Branch Size - A minimum or maximum
diameter size of branches to be removed should be specified in all
pruning operations. This establishes how much pruning is to be
done.
Pruning Objectives
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Hazard Reduction Pruning (HRP)-Is recommended
when the primary objective is to reduce the danger to a specific
target caused by visibly defined hazards in a tree. For example,
HRP may be the primary objective if a tree has many dead limbs
over a park bench.
-
Maintenance Pruning (MP)-Is recommended when
the primary objective is to maintain or improve tree health and
structure, and includes hazard reduction pruning. An example
here might be to perform an MP operation on a front yard tree.
Pruning Types
Hazard reduction pruning and maintenance
pruning should consist of one or more of the pruning types noted
below:
-
Crown cleaning - The selective removal
of one or more of the following items: dead, dying or diseased
branches, weak branches and watersprouts.
-
Crown thinning - The selective removal
of branches to increase light penetration, air movement and to
reduce weight
-
Crown raising - The removal of the
lower branches to provide clearance
-
Crown reduction or shaping - Decrease
the height and/or spread of a tree. Consideration should be
given to the ability of the species to sustain this type of
pruning
-
Vista pruning - The selective thinning
of framework limbs or specific areas of the crown to allow a
view of an object from predetermined spot
-
Crown restoration - Should improve the
structure, form and appearance of trees which have been severely
headed, vandalized or storm damaged.
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