www.arborage.com ARBOR AGE WINTER 2015 23
INDUSTRY INSIGHTS
Commission Bulletin 101," published most recently in 2011
and freely available on the web. "This is essential reading for
anyone involved in selecting trees for salt tolerance and/or
undertaking any form of salt related research," he said.
SELECT SALT-TOLERANT TREES
"Select the right tree species for the site," said Percival. "Salt
tolerance varies massively
between tree generations and
even between species within a
genus." For example, red and
sugar maples (Acer rubrum and
A. saccharum) are very sensitive
to salt spray, but hedge and
sycamore maples (A. campestre
and A. pseudoplatanus) are not. Japanese black pines (Pinus
thunbergii) can tolerate saline soils and salt spray, but white pines
(P. strobus) tolerate neither. English oak (Quercus robur) is much
more tolerant of salt that pin oak (Q. palustris).
Percival describes an interesting dichotomy: "You generally
find that tree species that are very tolerant of salt applied to
the roots tend to be sensitive to salt applied to the foliage and
vice-versa; so, when selecting a species for planting, make
sure there is an appropriate species/site fit." He said that in his
observation, street trees tend to suffer more from salt applied
via the roots, while in more open/exposed areas, trees are
PHOTO
BY
MICHELLE
SUTTON
really is not much research in this area that I am aware of. The
use of calcium magnesium acetate has proved effective and far
more environmentally benign than salt, but it is expensive and
therefore rarely used as an option."
Percival is currently evaluating the salt tolerance of many
ornamental trees whose salt tolerance was yet unknown
— trees that could prove useful in urban situations. "This
is a joint research trial with
Barcham Trees (a nursery in
Cambridgeshire, U.K.) who
have a phenomenal collection
of trees with which to use for
experimental purposes," said
Percival. "The system we are
using is a laboratory-based test
that is rapid and effective. Data will be available very soon."
SALT-WISE ACTIONS
Commercial arborists can't control how their clients'
municipalities run their deicing programs, but things arborists
can do to help prevent or mitigate damage to trees are as follows:
EDUCATE YOURSELF, YOUR CLIENTS AND LOCAL OFFICIALS
Arborists can educate themselves and others about soil salinity
and salt spray damage to trees. Percival recommends the
bulletin, "Deicing salt damage to trees and shrubs: Forestry
A surprising number of conifers can tolerate some salt exposure, but hemlock is especially intolerant.
"
Salt tolerance varies massively
between tree genera and even
between species within a genus.
"