UNITED STATES—Pruning techniques are very diverse to serve various purposes. Dormant pruning during winter concentrates resources for spring or summer growth. Hedging or shearing merely contains growth. Thinning or grooming removes superfluous growth to enhance sunlight diffusion. Clearance pruning directs new growth that might otherwise become obtrusive.
There are too many distinct pruning techniques to mention. Some, such as shearing and thinning, are mutually exclusive. Shearing actually initiates the sort of congested growth that thinning eliminates. Techniques such as dormant pruning and clearance pruning are mutually compatible. After all, almost all pruning is less stressful during winter dormancy.
Clearance pruning merely becomes a concern now as spring growth becomes obtrusive. Much of the worst requires professional assistance. Only arboricultural professionals can safely prune trees away from high voltage cables. Such cables are extremely hazardous! Utility services generally try to arrange such procedures before major problems develop.
Arboricultural professionals manage trees that are too big or too hazardous.
However, arboricultural professionals are necessary for other clearance pruning as well. Many trees are simply too large or hazardous for anyone but professionals. Some extend over roadways that need clearance for the largest of trucks. Some extend over chimneys that might ignite vegetation that gets too close. Many simply extend beyond a safe reach.
Street trees seem to require the most clearance pruning. They must be a specified height over any roadway, as well as over any sidewalk. Also, they must not obstruct street signs or views for cars backing out of driveways. Ideally, their interference with light from street lamps should be minimal. Vegetation that is closer to buildings presents other concerns.
Besides chimneys and exhaust vents, roofs also need clearance. Stems and foliage are abrasive as they move in any wind. They collect debris that causes rot and clogs gutters. Furthermore, walkways and navigable areas are more efficient with adequate clearance. Clearance pruning should direct growth away from any obstruction, rather than contain it.
Highlight: Honey Locust
Within its native range, wild thorny honey locust, Gleditsia triacanthos, is a nasty tree! Its wicked thorns are typically as long as four inches but can be twice as long. Some branch into many thorns or thick clusters of thorns. Thickets of young trees can be impenetrable. Female trees produce a messy abundance of brown pods that are about half a foot long.
Fortunately, its cultivars are much more docile. Most are exclusively male, so produce no pods. Old fashioned cultivars that might produce pods as they mature are now rare. More importantly, cultivars are thornless. That is why their common name is now honey locust rather than thorny honey locust. They are as remarkably resilient as the simpler species.
Most cultivars of honey locust grow no taller or wider than 50 feet here. Some grow only half as tall. Some of the more popular cultivars are brightly yellowish green for spring. At least one is ruddy bronze for spring. The finely textured foliage provides dappled shade. Leaves are pinnately and bipinnately compound and turn yellow for autumn defoliation. Individual leaflets are less than an inch long, so can be difficult to rake.
Tony Tomeo can be contacted at tonytomeo.com.
