Winter Tree Care: Safe Sidewalks and Driveways without Salt
Post on 21-May-2015
2405 Views
Preview:
DESCRIPTION
Transcript
Homeowner Alert
Tree Damage Caused by Chemical De-Icing Products
Road salt use in the United States was once considered the best method for de-icing roads and walkways.
De-icing chemicals were economical and considered to be the most effective method of making iced roads and walkways safe for use.
December 2013 Fairfax County Urban Forest Management Division,
Public Works and Environmental Services, Fairfax County, Virginia
1950 to Today Salt Use
• In 1950, fewer than 2 million tons of salt were used on US highways
• In 1988, about 10 million tons of salt were used on US highways
• Today, there may be as much as 20 million tons of sodium chloride (salt) spread or sprayed on highways each winter in the US
Anti-Icing• In some areas of the US, brine is used.
This is a mixture of rock salt and water. Applying brine before a snowfall, may prevent snow and ice from sticking to roads. This is known as anti-icing.
• The use of brine dramatically reduces the amount of salt needed and the time it takes to remove snow and ice from roads, according to the Conservation Law Foundation.
• For questions about substances uses on Virginia roads see VDOT.
• Products used for de-icing include calcium chloride and magnesium chloride
• These products are more expensive than traditional rock salt
De-Icing
Salt is Harmful to Trees
• Trees absorb salt through the air and soil when roads, sidewalks and driveways are spread or sprayed with salt
• Salt spray may travel 50 feet from the road
• Salt in the soil may create a physiological drought
• Tree roots cannot take in water
• A tree under stress from an overload of salt is “dying of thirst”
Salt is Harmful to Trees• The chloride in salt
may be taken up by tree roots, enter the sap, concentrate in the shoots and prevent buds from opening
• Salt restricts the ability of the tree to take up magnesium and potassium that are essential for making chlorophyll
Prevent Salt from Reaching Trees
Use salt alternatives on sidewalks and driveways• Non-sodium de-icing agents such as calcium chloride or
calcium magnesium acetate (CMA) • Other salt-free melting agents made from limestone and
acetic acid• Non-clumping cat litter or wood ashes• Coarse sand
• Cover trees with burlap if they are close to a road that may be salted• Erect barriers at road side with plastic fencing, burlap or snow
fencing
How to Diagnose a Salt Damaged
Tree**• Conifers that have been injured by salt show the damage in early
spring• Needles become yellow or broken, may drop off• Some needles may turn blue-green
• Deciduous trees develop a tuft called a “witch’s broom”• Flower buds may not open• Leaves may appear to be scorched or burned• Leaf margins turn brown prematurely
Generally, salt damaged trees have sparse foliage, may be stunted or yellow, and twigs may die back.
** Yates County Master Gardeners, Cornell University
How to Treat A “Salty” TreeIn the spring:
• Remove the mulch from around the tree and discard; mulch can trap a large portion of winter salt
• If drainage is good, wash the salt away from the top 18 inches of soil around the tree by watering thoroughly
In general:• Improve drainage around the tree roots• Avoid salting when trees are active in the fall and spring• Fertilize properly and only when necessary; carefully follow
directions on the package – more is not better!• Dormant trees are less likely to be harmed by salt
Plant Salt Tolerant Trees
Plant salt tolerant trees at least 30 feet from salted surfaces such as roads, sidewalks and driveways.
For a list of salt tolerant trees visit the Virginia Cooperative Extension
Young trees, with fewer roots, are more susceptible to salt injury.
Hedge maple Acer campestre
Hackberry Celtis laevigata
Fringetree Chionanthus virginicus
Ginkgo Ginkgo biloba
Several species are:Hedge maple Acer campestre
Hackberry Celtis laevigata
Fringetree Chionanthus virginicus
Ginkgo Ginkgo biloba
Southern Magnolia Magnolia grandiflora
For more information or to request this document in an alternate format call or email the Urban Forest Management Division, Department of Public Works and Environmental Services12055 Government Center Parkway (Herrity Building)Fairfax, Virginia 22035703-324-1770 TTY 711treemail@fairfaxcounty.gov
A Fairfax County, Virginia publication December 2013
Thank you.
top related