Hold the Salt

Hold the Salt

Months after crews' initial cleanup efforts, Hurricane Sandy's wrath continues to surface and cause concern for trees.

Last fall, Sandy's high winds carried spray from Long Island waters to land, splashing the surrounding area with sea salt. Unfortunately, the salty solution mist settled onto leaves and then into the soil once the excess water volume decreased. From there, salt residue seeped into the root systems of trees, plants and turf, leaving them brittle, brown and desperate for hydration.

Most recently, Northeast Davey crews have discovered these salty trees - specifically white pine and holly trees with a salt spray residue dusting their branches, bark, foliage and the soil below. Although the species typically tolerates salt spray, thousands of white pine trees within the Rye, Larchmont and Mamaroneck communities of New York, for example, have been affected.

As Davey crews monitor the region's trees for salt spray damage, which has primarily occurred on the eastern side of affected trees, facing the coast, they've encountered a lot of browning foliage. Some experienced arborists admit they haven't seen anything like this in 30 years.

Either salt spray mist settles on leaves and burns their edges through direct contact, or the spray seeps into the soil below and prevents moisture from reaching roots. "Water moves from high to low water potential areas," explains A.D. Ali, technical advisor for the Davey Institute in Ft. Myers, Fla. "When salt collects around the root system, the water potential in the roots is higher than that of the soil, so moisture is withdrawn from the roots, which dries out the leaves."

browned pine needles
When salt spray from ocean waters settles on leaves and needles (pictured), foliage turns brown as a result of desiccation. | Photo: Paul A. Mistretta, USDA Forest Service, Bugwood.com

Last month's 50-year record-breaking dry spell made conditions even more difficult for the tree victims to endure the salty swath. Similar to circumstances Midwestern conifers have notably suffered earlier this season, the drought has further impeded trees' abilities to recover from desiccation and revive their foliage.

As a result, salt spray has begun to burn the leaves on affected trees and brown the leaves' edges, a sign the trees' root systems are suffering. "When little to no precipitation occurs, the salt remains in the soil," Ali explains. "Additional irrigation will benefit those severely moisture-deprived roots," he adds.

Ali suggests deep watering plant material that has suffered salt spray damage. However, he advises to avoid watering too much at once to prevent excessive moisture collection at the roots and more poignantly, root rot. "Activate a portable sprinkler 20 to 30 minutes a day near the plants that need it most, especially in sandy soils," Ali says. "A constant, slow flow of water is ideal."

Before deep watering your desiccated plants, familiarize yourself with the type of soil on your property to avoid causing further damage. Fortunately, sandy soils allow water to flow freely and therefore leach salt from the ground; however, clayey soils retain more water and hinder salt deposits from trickling away from roots.

burned foliage
The Southern magnolia leaves shown here suffered burned foliage as a result of Hurricane Ike in Galveston, Texas. | Photo: A.D. Ali

Ali has experience addressing salt spray damage after hurricanes; Charlie and Ivan both left behind salt deposits along Florida's coasts. "Some trees are more tolerant of salt spray than others," Ali says, adding after past storms he has noticed the typical burned foliage on affected Southern magnolia trees.

Because salt spray exposure not only causes stem and foliage disfigurement, or worse, reduced growth and plant death, consistent monitoring even months after a hurricane is critical to the health of your plants.

Contact your local professionally trained arborist for a consultation of your trees to determine the best approach to returning them back to good health. Perhaps he or she will suggest deep fertilization to help generate additional foliage or selective trimming to improve the canopy's appearance.

Storm restoration continues with the care of your trees. Just a bit of extra attention can help revitalize your trees to the conditions they exemplified before Hurricane Sandy splashed ashore, seasoning them with a heavy helping of unwanted salt.

  • Linda Elliott April 9, 2017 >Thank you for your article hold the salt, I have a water softener and I have been letting my washer drain water my tree and I guess the salt from the softener is causing my problem the leaves on my magnolia have a brown edge and falling off I hope I stopped it soon enough to save it thanks again. Linda Elliott
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