Table 3.

Structural defect definitions.

Codominant stemsStems “Equal in size and relative importance, usually associated with either the trunks or stems or scaffold limbs....” (Harris et al. 1999) Recorded if it occurred anywhere in the main stem, either low or high on the stem.
Included barkWhere bark is turned inwards at branch junctions instead of being pushed out (Harris et al. 1999), resulting in the branch or stem being weakly attached and prone to fracturing (Shigo 1991; Smiley 2003). This may occur anywhere in the canopy from small branches to codominant stems and stem should be pruned back or the whole tree removed.
Low branchingCanopy lift required. Branches low on the stem of a tree that has established or branches encroaching on the road or pathway. The removal of low branches earlier rather than later reduces the wound on the trunk. If branches were encroaching on paths or roads, they were also canopy lifted. These were listed as a fault to be pruned.
Epicormic shoots“Sprouts upon the trunk” (Shigo 1991). They are not well attached to the trunk or stem and can present a hazard by breaking when they get larger.
SuckersNormally arise from roots at or below the soil surface. They are often shoots from rootstock to which the tree was grafted. Suckers can be vigorous and are not the desired cultivar.
Broken branchesBranch may not completely break off and continue to grow with a weak point becoming a danger. Broken branches were pruned.
Broken stemsMain stem is broken. Most of these trees needed replacement due to the structural defect that existed.
DeadwoodDeadwood in the canopy requiring removal. Usually coincides with a low health rating.
Rubbing or crossingBranches rubbing against each other wound, which not only weakens the branch but provides an open wound for entry of pathogens. Removal eliminates the weak point; the tree can heal over quickly and the integrity of the tree is not compromised. Rubbing branches were pruned.