Originally posted by ROLLACOSTA
cuts going back to growing points..
Yes, RC, Yes, growing points are nodes, and nodes are natural targets whether or not a lateral branch is present.
Below is a sneak preview:Restorative heading cuts are not random and predetermined, like topping cuts, but selected according to biological criteria. Primordial nodes are only growth points where leaves grew out of the bark. They will put out relatively weak growth that is only attached to the bark. Branch nodes contain preformed buds, once associated with a terminal bud, that are connected to the vascular stream and often anchored by compacted xylem. The following characteristics can make branch nodes good natural targets:
BUMPS, BULGES AND WRINKLES
BUMPS on branches can indicate locations of nodes. Preformed lateral buds, complete with scales, are tucked into some of these bumps. Sometimes visible to the naked eye, they are ready to assume apical dominance. Inside some of these buds, pith trails into the heart of the parent are enclosed by compacted xylem. Research is needed to establish how well this deep grip attaches the growth from these latent buds. But after this storm the best targets had to be chosen, and the tree’s response managed. Bumps caused by galls or cankers or other diseases differ greatly in appearance. These conditions indicate an inappropriate location for a heading cut; the target must contain sound wood and a CODIT wall.
BULGES just before a decrease in diameter are often target indicators. Taper often changes at terminal nodes, so a cut just outside a bulge will retain more symmetry and structure. If drop-crotching exposes the remaining branches to more stress and strain, will the tree be safer than if heading cuts were made? “When exposed by the removal of neighboring stems, previously sheltered and mechanically reliable body parts may deform or break even under wind conditions that are ‘normal’.”6 The damping effect of limbs, for years thickened by torque, is altered while other branches thicken under the new load.
WRINKLES on leaders near bumps and bulges can resemble the swollen collars that form around the base of branches. If a lateral branch was shed at these locations, there may already be preformed lateral buds on the outside and also the “unique chemical barrier called the branch protection zones”7 Are sealed branch stubs natural targets because they contain both preformed lateral buds and these chemicals that protect against decay? Research into the chemical constituents within different nodes is needed to determine the suitability of different targets.
