ISA Chapter 8 - Pruning (copy)

ANSI A300

In the United States, industry-developed, national consensus standards of practice for tree care.

Antigibberellin

Plant growth regulator that inhibits the action of the plant hormone gibberellin, which, among other things, regulates cell elongation.

Branch Bark Ridge

Raised strip of bark at the top of a branch union, where the growth and expansion of the trunk or parent stem and adjoining branch push the bark into a ridge.

Branch Collar

Swollen area where a branch joins the trunk or another branch that is created by the overlapping vascular tissues from both the branch and the trunk.

Branch Protection Zone

Chemically and physically modified tissue within the trunk or parent branch at the base of a smaller, subordinate branch that retards the spread of discoloration and decay from the subordinate stem into the trunk or parent branch.

Branch Removal Cut

Pruning cut that removes the smaller of two branches at a union or a parent stem; pruning cut that removes a branch at its point of origin.

Branch Union

Point where a branch originates from the trunk or another branch.

Clearance Pruning

Pruning to reduce interference with people, activities, infrastructure, buildings, traffic, lines of sight, desired views, or the health and growth of other plants.

CODIT

Acronym for Compartmentalization Of Decay In Trees

sometimes interpreted as compartmentalization of damage or dysfunction in trees.

Codominant Stems

Forked branches of nearly the same diameter, arising from a common union and lacking a branch collar; may have included bark.

Compartmentalization

Natural defense process in trees by which chemical and physical boundaries are created that act to limit the spread of disease and decay organisms.

Directional Pruning

Selective removal of branches to guide and/or discourage growth in a particular direction.

Espalier

(1) A pruning system that develops a plant in a plane, such as along a wall or a fence. (2) A plant trained in that manner. (3) To train plants in that manner.

Frond

Large, divided leaf structures found in palms and ferns.

Heading Cut

Pruning cut that removes a branch or stem

between nodes (leaving a stub), to a bud, or to a live branch

that is less than one-third the diameter of the stem being removed.

Included Bark

Bark that becomes embedded in a crotch between branch and trunk or between codominant stems and causes a weak structure.

Inflorescence

Cluster of flowers.

Internodal

Between the nodes on a stem.

Lateral

Secondary or subordinate branch or root.

Leader

Primary terminal shoot or trunk of a tree. Large, usually upright stem. A stem that dominates a portion of the crown by suppressing lateral branches.

Lion Tailing

Poor pruning practice in which an excessive number of branches are thinned from the inside and lower part of specific limbs or a tree crown, leaving mostly terminal foliage. Results in poor branch taper, poor wind load distribution, and a higher risk of branch failure.

Permanent Branches

In pruning, branches that will be left in place for the life of the tree, often forming the initial scaffold framework of a tree.

Plant Growth Regulator

Compound effective in small quantities that affects the growth and/or development of plants may be naturally produced (hormone) or synthetic.

Pollarding

Semiformal pruning system that maintains crown size by initial heading of branches on young trees or young portions of older trees, followed by removal of sprouts to their point of origin at appropriate intervals, without disturbing the resulting pollard heads.

Pruning Objectives

The defined purpose(s) for pruning (e.g., provide clearance, reduce risk).

Pruning System

Technique or procedure that is applied to develop the desired long term form of the plant.

Reduction

Pruning to decrease height and / or spread of a branch or crown.

Reduction Cut

Pruning cut that removes the larger of two or more branches or stems, or one or more codominant stem(s), to a live lateral branch, typically at least one-third the diameter of the stem or branch being removed.

Restoration

Pruning to improve the structure, form, and appearance of trees that have been vandalized, damaged, or improperly pruned.

Scaffold Branches

Permanent branches that form the scaffold or structure of a tree.

Shearing

Cutting leaves, shoots, and branches to a desired plane, shape or form, using tools for that purpose, as with hedges.

Structural Pruning

Pruning to influence the orientation, spacing, growth rate, strength of attachment, and ultimate size of branches and stems.

Subordinate

Prune to reduce the size and ensuing growth of a branch in relation to other branches or leaders. (2) Dominated by other trees or branches, suppressed.

Temporary Branches

Branches that should be retained temporarily because they provide energy back to the trunk, contribute the trunk taper, and provide shade to young trunk tissue.

Three-Cut Method

Branch removal technique consisting of an undercut and then a top cut, usually made farther out on the branch, followed by a third cut to remove the stub.

Topiary

Formal pruning system that uses a combination of pruning, supporting, and training branches to orient a plant into a desired shape.

Topping

Reduction of tree size by cutting live branches and leaders to stubs, without regard to long-term tree health or structural integrity.

Watersprout

Upright, epicormic shoot arising from the trunk or branches of a plant above the root graft or soil line. Incorrectly called a sucker.

Wound Dressing

Compound applied to tree wounds or cuts.

Woundwood

Lignified, differentiated tissues produced on woody plants as a response to wounding.