BERTAUSKI COLUMN: Cabling can help support weighty tree limbs
Getting older requires a different approach to life. It means scheduling exercise, more frequent health screenings and dietary awareness.
Trees can live 10 times longer than the average adult and also need care adjustments as they age.
Young trees might need to be staked to handle strong winds and occasionally watered and fertilized. As the tree matures, the root system spreads deep and wide to find soil moisture and nutrients.
It also anchors the tree firmly in the ground. In many cases, limbs and trunks are more likely to break during a storm than the entire tree being uprooted.
In the Lowcountry, many properties are valued for their live oaks. A mature live oak canopy can spread 100 feet or more with massive sprawling branches that, in some cases, rest on the ground. These specimens are hundreds of years old, having witnessed the Civil War and, perhaps, the American Revolution. Their value, in our lifetime, is irreplaceable.
In some cases, selective pruning by a trained arborist can correct deficiencies and lighten weighty limbs. However, there are unique arboricultural techniques that may be applied to these living relics that aren't necessary for most other trees in our landscape. The weighty limbs can, over time, become susceptible to failure due to size and lack of support. Without some help, the loss of a major limb can alter the value and even the health of the tree.
Cables and braces can be installed to provide additional support to the entire tree canopy. Susceptible limbs are connected to the trunk or other limbs by means of an eye-bolt and steel cable (all rust proof).
An arborist drills the eye-bolts directly into the wood as a permanent installation. While not all arborists agree, many consider the wounding required to install eye-bolts and braces to be minor, and that the benefit of additional support outweighs the damage.
In most cases, multiple cables are required to sufficiently support the canopy. Certified arborists will follow American National Standards Institute specifications to ensure proper design and installment.
Bracing utilizes sturdy steel rods to reduce the spread of two leaders, or main trunks. As two or more leaders develop, the junction between them can weaken and become susceptible to splitting. In some cases, this could put half the tree at risk of breaking off. Bracing also can be used to support a weak union of a large branch.
Weathering the storm
Cabling and bracing is especially beneficial during violent weather. High winds put less stress on weak unions and susceptible branches when the canopy has that extra support.
Angela Livingston, horticulturist at Mulberry Plantation in Moncks Corner, says that she's noticed that cabled and braced trees sustain much less damage. Additionally, unsupported trees can sustain irreparable damage.
In addition to structural support, Livingston has to be concerned with lightning damage to their prized live oaks.
The large trees are very susceptible to lightning strikes, which can immediately kill them.
Lightning brings the moisture within the tree to an instantaneous boil, which destroys the interior cells and blows bark off the trunk.
Many of Mulberry Plantation's trees have a lightning rod installed near the top of the canopy. The metal of the lightning rod is a better conductor of electricity than the moisture of the tree. A metal cable is run from the lightning rod, down the trunk and out to ground rods driven into the soil beyond the canopy. The cable is attached to special fasteners that keep the cable away from the trunk.
With this system, a lightning strike will travel down the cable and disperse into the ground rather than running inside the tree.
With special care to elderly trees, irreparable damage can be avoided for years to come.
Tony Bertauski is a horticulture instructor at Trident Technical College. To give feedback, email him at email@example.com.