The harshest growing conditions for trees lie in urban and community landscapes, including private yards. Unfortunately, these trees are also the ones with the highest value and the ones that pose the greatest loss to people when storms strike. Storms can bring high winds, heavy rains and lightning strikes that cause trees to lose branches, split, break and uproot.
After the Storm
Following the storm, homeowners can follow these steps to save what is salvageable and minimize the damage:
1. Assess
the damage. The morning after a storm survey each tree and answer these
questions:
- Is the tree in
the right place? If the tree is not the right tree for its location (e.g., a
very large species in a small spot), consider removal.
- Is the tree
basically healthy? If the tree is otherwise healthy and in the right place and
the structural damage seems minor, the tree should survive and recover.
- Are major limbs
or the tree’s leader (the central, main branch growing upward) damaged or lost?
Losing large branches and the main leader makes it very difficult for the tree
to recover. Although it may survive, it may become stunted and/or succumb to
insect pests and diseases.
- Did the tree
lose more than half of its branches? A tree that loses more than 50% of its
branches may not re-grow enough leaves to nourish the tree, and may it may
survive for only one or two more seasons.
- How large are
the wounds caused by branch loss? Large wounds heal very slowly. Ragged wounds,
for example, where the bark is stripped away from the main branch or trunk, may
never heal. Both kinds of wounds can make the tree vulnerable to insect pests
and diseases.
- Can remaining
branches form a new structure for the tree? The limbs that remain after the storm
and clean up will grow vigorously. Will they be able to fill out the gaps in
the tree?
2. Decide
whether the tree is a keeper, a borderline case or one that needs removal.
- Keepers. These
are the trees that have only slight damage. Prune broken branches, repair torn
bark and rough edges around wounds, and let the tree heal itself. Trees that
retain most of their strong limbs, trees that lose only one major branch (and
are otherwise undamaged) and trees that are just too young to die can be
keepers.
- Borderliners.
These are trees that are valuable, seem otherwise healthy, and you just don’t
want to lose. It’s worth the time and expense to have these trees assessed and
treated (if needed) by a professional arborist whom you trust. Be careful not
to go overboard with pruning. Trees need all their leaves to feed themselves –
the more healthy tissue you remove, the harder it is for the tree to recover.
Remove only what is necessary to make the tree stable and safe.
- Leave takers.
Say adieu to trees that lose most of their leafy crowns. Such a tree will not
be able to replace enough leaves to survive and will not regain its beautiful
shape. You also must bid farewell to a tree that has a rotten inner core or
other fault that caused its trunk to split. Although such a tree may be able to
survive for years, it will never be healthy and will be so weakened
structurally that it is a hazard. These hopeless cases usually cannot survive.
3. Provide
first aid and TLC to keepers and borderliners. Don’t be too hasty in deciding
to remove trees. Sometimes a little TLC can make the difference between a tree
keeping its place in your landscape and having to be removed.
- Safety first!
Look up, down and sideways. Do not walk or stand under branches that are hanging
or hung up in other branches – a branch as small as a baseball bat can kill
you! Stay clear of leaning trees.
Watch out for
downed power lines and stay well clear of them. Even low-voltage lines such as
telephone, cable and security fences can pack a lethal wallop. Branches coming
into direct contact with power lines and those near energized lines can become
electrically charged and pose a serious threat to anyone who touches them. Do
not attempt any clean up until you are 100% certain the lines are dead.
- Get advice from
a pro. If the cleanup requires you to climb, use a ladder, use a chainsaw
either one-handed or overhead, or if the branches to be removed are larger than
4 inches in diameter, call a professional, state-licensed arborist. Arborists
have the know-how, the skills and the equipment needed to do the job well and
safely.
- Provide TLC
where you can. Torn or stripped bark occurs when branches break away from the
main stem or trunk. You can use a chisel of sharp (clean) knife to trim the ragged
edges on tears. Try not to cut more of the bark away than is necessary to
smooth the edge of the tear – a smaller, narrower wound heals faster.
- Trees and large
shrubs that need to be reset or straightened should be staked until they become
reestablished. Use metal or hardwood stakes that will last for months, but be
sure not to drive stakes through any major roots. Place stakes at an angle away
from the trunk to provide the greatest support. Use a wide strap or cloth that
will reduce abrasion of the bark, and if you use wire or cable, be sure to run
it through short lengths of old garden hose to cushion the bark. Be sure to
leave a small amount of slack in the strap, wire or cable. Secure the plant
from three sides to prevent excessive movement during high winds and rains.
Remove the staking as soon as possible; remove all staking by 12 months to
avoid the plant outgrowing the staking system, which can kill the plant. Treat
reset and straightened trees like they were newly planted; irrigate more frequently
than established plants and hold back the fertilizer for at least a year.
- Remove broken
branches that are still attached to the tree, and trim any tears in the bark.
Homeowners can prune out small broken branches (that they can reach safely) – cut
where the branch joins the trunk or larger branch, just outside of the swelling
rear at that juncture (called the branch collar). Homeowners should call in a professional to
remove larger broken branches; remember tree branches are large, heavy and difficult
to manage. This means they can be very dangerous for a novice to remove. Don’t
take any chances – hire a professional.
- Don’t top your
trees (cutting main branches back to stubs). Topping may seem like the best way
to prevent large branches from falling the next time, but in reality this
practice removes most of the leaves, and keeps the tree from producing enough
food to recover from the storm. Topping also creates a large number of large
wounds on the tree inviting pests and diseases and further draining the tree’s
energy reserves, again making recovery difficult, if not impossible.
- Prune to
correct future problems: (1) on smaller trees, prune out multiple leaders to
one main leader. Multiple leaders (more than one “main” stem growing upward) are
very vulnerable to splitting in high winds, creating hazards and significant
structural damage to trees. (2) encourage good branch angles. Branch angles at
10 o’clock and 2 o’clock (approximately 20 inches from main trunk) tend to be
the strongest. (3) Don’t cut branches in a way that leaves stubs. Branches that
grow from stubs often have weak attachment to the main branch and will likely
fail as they get larger.
Before the next storm
On first glance
after a storm, it appears that damage is random or haphazard. On closer
inspection, though, there are clues as to why some trees stand and some trees
fail during storms. How can homeowners help minimize loss of valuable, much
loved trees? Knowing what to do ahead of storm season is key.
Put the right
tree in the right place. Careful selection of the plants you put into the
landscape can help avoid problems down the line. Pick small species (hollies,
redbuds, dogwoods, hawthorns and crape myrtles) for restricted spaces such as near
structures, pathways (such as drives, roads and sidewalks) and power lines.
Leave the large open areas for planting oaks, sycamores, hackberries,
sweetgums, elms, beeches, hickories, pecans, poplars and other large species.
Prune young trees
to develop the strongest structure. Getting the structure of the tree correct
early on in a trees life helps you avoid the need to prune out large branches
later on, potentially harming the tree.
Take care of the
root zone. Root problems commonly put trees at risk during storms. Damaged
roots and tree root zones constricted to small spaces are common in planted
trees and lead to many of the problems seen during storms, such as wind throw.
Mulch your trees to help protect roots and trunks. A 2-4 inch layer of mulch
correctly applied improves the soil for root growth, helps conserve soil
moisture and moderates temperature extremes (cold and hot). Proper mulching
reduces competition from grass and reduces mechanical damage from mowers and
string trimmers. Make sure that the tree has adequate rooting space for its
size. The critical root zone for a tree can be considered the area under its
canopy, though in reality, the root system extends far beyond this.
In addition to
matching a tree to its site in terms of mature size and cultural needs (water/drainage,
nutrient, temperature and light requirements), relative wind resistance of a
species is something to consider.
- High wind
resistance: southern magnolia, live oak, cypress, sweet gum, dogwood, hollies,
palms.
- Medium-high
wind resistance: Japanese and
Florida
sugar maple, river birch, hickories, red bud, sweetgum, white oak, swamp
chestnut oak, Schumard oak, winged elm.
- Medium-low wind
resistance: boxelder, red & silver maple, sugarberry, camphor, green ash,
wax myrtle, sycamore, American elm, slash, loblolly and longleaf pine.
- Lowest wind
resistance: southern red, laurel & water oak, pecan, tulip poplar, Bradford
pear, tallow, Chinese elm, southern red cedar, Leyland cypress, spruce pine.
Contributor: Hallie Dozier, Louisiana State University
Agricultural Center
Adapted from:
Duryea, M., E. Kampf & R.
Littell, Wind and Trees in the Urban
Forest: Lessons Learned from 9
Hurricanes. Presented at the 64th International Society of Arboriculture Southern
Chapter Conference,
Birmingham,
AL, April 3, 2006.
Fazio, J.R. 2000. Tree City USA
Bulletin No. 2 “When a Storm Strikes.” National Arbor Day Foundation.