Winter Tree Care: Safe Sidewalks and Driveways without Salt

1. Tree Damage Caused by Chemical De-Icing
Products
Homeowner Alert
Road salt use in the United States was once considered the best method for deicing 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

2. 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

3. 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.

4. De-Icing
• Products used for de-icing
include calcium chloride
and magnesium chloride
• These products are more
expensive than traditional
rock salt

5. 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”

6. 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

7. 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

8. 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

9. How to Treat A “Salty” Tree
In 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

10. Plant Salt Tolerant Trees
Several species are:
Hedge maple
Hedge maple
Hackberry
Hackberry
Acer campestre
Acer campestre
Celtis laevigata
Celtis laevigata
Fringetree
Fringetree
Ginkgo
Ginkgo
Chionanthus virginicus
Chionanthus virginicus
Ginkgo biloba
Ginkgo biloba
Southern Magnolia
Magnolia grandiflora
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.

11. 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 Services
12055 Government Center Parkway (Herrity Building)
Fairfax, Virginia 22035
703-324-1770 TTY 711
treemail@fairfaxcounty.gov
A Fairfax County, Virginia publication
December 2013
Thank you.