Ilene Sternberg is a multiple-award-winning freelance garden writer and co-author of Best Garden Plants for Pennsylvania and Perennials for Pennsylvania.

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Damaged Trees
by Ilene Sternberg    

Storms, wind, cold temperatures, the freeze-thaw cycle — all of these can injure trees and shrubs. What’s a gardener to do?

Types of Tree Injuries

Broken branches – these should be cleanly pruned back to the collar of the larger branch or trunk to which they are attached. This protects the tree from decaying fungus that can infect an improperly pruned wound. Get a good manual, take pruning lessons or hire an arborist to fix the damage. (He’ll also dispose of all cut branches and debris and may even chip them into lovely mulch for you to use!)

Branches that are bent by heavy, wet snow or ice – don’t try to knock it off the tree. Let ice melt and allow the tree to slowly reclaim its natural shape. Most young trees, including evergreens, have flexible stems and may easily recover from the bending.

Winterburn – this is seen as browning or scorched leaf tips on evergreen foliage, usually from needle tips downward, and it is usually attributed to loss of water through leaf transpiration. Winter sun and winds dry needles. Applying an antidesiccant helps reduce transpiration and minimizes damage. At least two applications per season, one in December and another in February, will provide protection all winter.

Frost cracks and sunscald on the south or southwest sides of trees is caused by temperature extremes and are generally cosmetic and do little harm to the tree. To prevent sunscald, you can wrap the tree from trunk to first branch in winter, removing the wrap in spring, or plant evergreen shrubs near enough to shade the tree trunk in winter.

Root tissues, especially on shallowly rooted plants, can be severely injured by soil temperatures below 15 F.

Lightning strikes, trees being uprooted, flood and tornado damage may require professional help. 

Hiring Help

There is a profound difference between a licensed arborist and a “guy with a chainsaw.” There are national and state associations for arborists. One widely accepted certification in the tree care industry is that granted by the International Association of Arboriculture, often referred to as “ISA Certified.” (Visit the International Society of Arboriculture at isa-arbor.com.) Arborists should be certified, insured and capable of diagnosing disease, fungus or insect problems. Some tree care professionals are only qualified to remove trees, not to prune or detect and treat specific maladies. Inquire before you hire. Ask to see evidence of the individuals or company’s insurance for personal and property damage and workers’ compensation.

Ask for and check local references or past clients. Obtain cost estimates from several arborists. Ask for a written estimate listing all work to be done. Don’t pay for the job until everything agreed upon is completed. Be patient and be prepared to wait to get the work completed by a qualified arborist, especially after a storm.

Prevention

Trees with Exceptional Storm Resistance

Arborvitae, Western red cedar (Thuja plicata)
Carolina beech (Carpinus caroliniana)
Catalpa (Catalpa speciosa)
False cypress (Chamaecyparis spp.)
Fir (Abies spp.)
Ginkgo (Ginkgo biloba)
Hemlock (Tsuga spp.)
Horsechestnut (Aesculus hippocastanum)
Incense cedar (Calocedrus decurrens)
Eastern hop hornbeam (Ostrya virginiana)
Kentucky coffeetree (Gymnocladus dioicus)
Littleleaf linden (Tilia cordata)
Several Oaks (Quercus spp.)
Ohio buckeye (Aesculus glabra)
Paperbark maple (Acer griseum)
Shagbark hickory (Carya ovata)
Silver linden (Tilia tomentosa)
Spruce (Picea spp.)
Sweetgum (Liquidambar styraciflua)
Vine maple (Acer circinatum)
Black walnut (Juglans nigra)
Yew (Taxus spp.)

Select hardy species and cultivars. When planting, stake and tie trees loosely so stems can bend in the wind. Slacken and eventually remove the ties after root systems are well established (usually five to seven years).

Proper pruning is essential.

When snow or ice is expected, tie up the branches of upright evergreens, such as ‘Skyrocket’ juniper (Juniperus scopulorum ‘Skyrocket’), to keep them close to the tree.

Occasionally, trees may be cabled to support them from breakage during storms, but this is usually reserved for special, historic or otherwise revered specimens, as the procedure is expensive and must be maintained annually.

To prepare trees for winter, avoid late-summer fertilization or pruning, which might stimulate new growth. Water trees and shrubs, especially evergreens, during dry periods until the ground freezes. Mulch to conserve soil moisture and insulate the roots from cold temperatures. Do not mound mulch against tree trunks! This is a terrible practice in all seasons as it can rot the bark and smother the root systems and in the winter, mice and rabbits will feed on the bark and girdle the trees, especially in prolonged heavy snow cover. Rabbits feed on the bark above the snow, while mice feed near ground level. Mouse damage is usually more severe when trees are surrounded by thick grass, weeds or heavy mulch, so maintain an area free of grass or weeds 1-2 feet out away from the base of trees. 

Protect evergreens from wind and salt spray with burlap screens. Apply antidesiccant (such as Wilt-Pruf™ or Vapor Gard™), to trees and shrubs in late fall. Wrap trunks and major branches of newly planted trees with burlap or commercially available tree wrap products; remove in the spring.

Trees that Could Topple

The following trees grow big enough to sustain or cause serious damage and are also prone to falling in high winds due to their weak wood or poor branching structure.

American linden (Tilia americana)
Black cherry (Prunus serotina)

Black locust (Robinia pseudoacacia)
Box elder (Acer negundo)
Bradford pear (Pyrus calleryana ‘Bradford’)
Cottonwood (Populus deltoides)
Dawn redwood (Metasequoia glyptostroboides)
Elms (Ulmus spp.)
Green ash (Fraxinus pennsylvanica)
Hackberry (Celtis occidentalis)
Hickories (Carya spp.)
Honeylocust (Gleditsia triacanthos)
Pecan (Carya illinoinensis)
Laurel oak (Quercus laurifolia)
Poplars (Populus spp.)
Red cedar (Juniperus virginiana)
Red maple (Acer rubrum)
River birch (Betula nigra)
Silver maple (Acer saccharinum)
Tulip poplar (Liriodendron tulipifera)
Water oak (Quercus nigra)
White pine (Pinus strobus)
Willows (Salix spp.)

From State-by-State Gardening September/October 2013.
Photos courtesy of The Davey Tree Expert Company.

 

Posted: 11/27/13   RSS | Print

 

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