ISA Arborist-Chapter 8 Pruning

ANSI A300 In the USA, industry developed, national consensus standards of practice for tree care. antigibberellin Plant growth regulator that inhibits the action of the plant hormone gibberllin, which, among other things, regulates cell elongation. Apical control Inhibition of lateral buds, decreasing from top down, by apical buds over many seasons, resulting in trees with an excurrent growth form. Branch bark ridge Raised strip of bark at the top of the branch union, where the growth and the expansion of the trunk or parent stem and adjoining branch push the bark into a ridge. Branch collar Area where a branch joins another branch or trunk that is created by thr overlapping vascular tissues from both the branch and the trunk. Typically enlarged at the base of the branch. Branch protection zone Chrmically and physically modified tissue within the trunk or parent branch at the base of a smaller, Subordinate branch that retards the spread of discolorization and decay from the subordinate stem into the trunk or parent branch. Codominant stem Forked stems nearly the same size in diameter, arising from a common junction and lacking a normal branch union 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. Crown cleaning In pruning, the selective removal of dead, dying, diseased, and broken branches from the tree crown. Espalier Training plants to grow on a fence, specialized type of pruning. Frond Large, divided leaf structures found in palms and ferns. Heading Cutting a shoot back to a bud or lateral branches not large enough to assume apical dominance, cutting an older branch back to a stub in order to meet pruning requirements. Including bark Bark that becomes imbedded in the crotch (union) between branch and trunk or between codominant stems. Causes a weak structure. Internodal Between nodes on a stem Lateral Secondary or subordinate branch on a 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 surpressing lateral branches. Lion tailing Poor pruning practice in which a excessive number of tree branches are thinned from the inside and lower part of limbs or a tree crown, leaving terminal foliage. Result is poor branch taper , poor wind load distribution, and a high risk of branch failure. Permanent branch In structural pruning of small trees, branches that will be left in place, often forming the initial scaffolding framework of a tree. Plant growth regulator Compound effective in small quantities that effects the growth and or development of plants. Naturally produced or synthetic. Pollarding Specialty pruning technique in which a tree with a large mature form is kept relatively short. Starting on a young tree, internodal cuts are made at a chosen height, resulting in the development of callus limbs at the cut height. Requires regular, usually annual, removal of sprouts arising from the cuts. Raising Selective pruning to provide vertical clearance Reduction Pruning to decrease the height and/or spread of a branch or crown. Reduction cut Pruning cut that reduces the length of a branch or stem back to a lateral branch large enough to assume apical dominance. Restoration Pruning to improve the structure, firm, and appearance of trees that have been improperly trimmed, vandalized, or damaged. Also, is a management practice of planting to restore altered or damaged ecosystems or landscapes. Scaffolding branch Permanent or structural branches that form the scaffolding architecture or structure of a tree.