With majestic beauty, mature trees can provide shade in summer months, enhance a landscape and even increase a home’s value.
Until the winds howl.
When Santa Ana winds rake the Southland, mighty trees can become lethal to homes, automobiles and hapless people caught in their path as they come crashing down.
What’s a harried homeowner to do?
Not much when the winds are howling, experts say, but plenty before they blow.
“Windstorms often come up in the middle of the night, and not much can be done at that time,” said Ross Holmquist, a landscape designer with Lawson Landscape Services in San Juan Capistrano. “But some important steps should be taken in summer or fall, before the Santa Ana season is upon us.”
In his 23 years as a landscape designer, Holmquist has worked with homeowners, companies and municipalities to maintain their trees.
“When strong winds blow, especially after heavy rainfall like happened here just a few weeks ago, the huge, heavy mass of foliage pulls a tree down,” he said. “It’s important to keep trees laced out so the wind blows through them.”
Holmquist and other horticultural experts recommend that once trees grow to 10 to 15 feet, they be pruned by professional arborists or trimmers.
Holmquist recommends pruning trees according to their varieties and ages. Fast-growing trees such as coral, which he says are particularly prone to wind damage, should be thinned every six months--in June and December--to keep their centers open, he says.
Don Case, a certified arborist in Fullerton, warns against topping a tree--removing its central leading growth and leveling it at a certain height.
“Topping causes rapid growth of new branches near the cut, and those branches are attached just to the outer bark, instead of the heart of the tree,” said Case, an arborist of 26 years. “In time, those branches are very prone to breakage.”
Trees can also be weakened by fungi that can enter through topping cuts.
He recommends a systematic thinning, especially on trees such as eucalyptus that, while useful as windbreaks, are also prone to branch failure. “Thinning out” means that entire branches are removed.
Deep watering the root zone in dry months promotes deep root growth, but be careful not to over-water, because that can lead to root diseases. Oaks are especially susceptible; mature oaks that topple often have root diseases.
Another preventive measure Holmquist suggests is staking young or recently planted trees.
Typically trees at nurseries are potted and attached to a stake.
“Usually, this stake is only in the tree’s root ball and should be replaced when the tree is planted in the ground,” Holmquist said. “It’s better to place two stakes, one on each side of the tree, inserted into the sub-basin. The tree should be secured by two rubber ties, which will allow the tree to move when it’s windy without damage to the bark.”
He advises using lodge pole stakes of at least 2 1/2 inches in diameter. These can be found at nurseries and home improvement centers, along with the rubber ties. He avoids redwood stakes because they deteriorate quickly.
Young trees should remain staked during their first few years, he said. Mature trees can be secured by guy wires or cable. To prevent anyone tripping over the wires, pass them through PVC pipe so they can be readily seen.
After the winds have calmed, survey your property for any trees that may have been weakened. Those that have don’t necessarily have to be removed. You can reduce their height and mass by skilled lacing and staking them if they are small enough.
“If you treat trees well and take care of them properly, they should withstand winds,” Case said.
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Standing Tall, Prone to Fall
Trees most prone to branch failure in winds are those with weak or brittle wood, including:
* Chinese lantern
* silk oak
Trees that can withstand winds include:
* American arborvitae
* holly oak
* Southern live oak