Caring for your trees this Fall

Fall Tree Prep

For most homeowners with a yard full of lush green trees, fall means vibrant, changing leaves—on the trees and on the lawn. When most of the leaves have been bagged or composted, and you’ve put away your rake for the season, it’s time to take stock of your trees. They’re in a period of transition and need some extra attention to get them through the winter.
Without their leaves, it’s easy to inspect for storm damage, dead branches, disease or insect damage. And next spring, when it’s time for them put out new growth, your trees will thank you for spending some time with them now.

Examine the bark

After a summer of yard work, a few of your trees may have endured swipes from your lawn mower or nicks from your weed eater. Check the bark around the base of their trunks.
Wounded areas can suffer from decay, and nicks in the bark can be an entryway for diseases that have a tendency to enlarge the affected area. Most minor wounds can heal themselves with time. Cut off any jagged edges of bark with a utility knife to speed healing, and watch the wound to make sure it doesn’t get infected.
While you may have already retired your mower for the summer, remember next year to take care around trees, trimming weeds by hand—or using an herbicide or mulch—to keep grass and weeds away from the tree base and roots.
Summer storms may have also caused damage to some of your trees; a common sign of a lightning strike is loose bark that hangs in strips. Loosened bark can be a sign of internal wood damage that would otherwise go unnoticed. If you see signs of lightning damage, start by removing any damaged branches. Then give your tree plenty of TLC—fertilizer, water and a layer of mulch. Trees that suffer from lightning strikes often survive and grow to be healthy trees; however, internal damage can cause considerable stress that could slowly damage your tree over a period of years.
In addition to lightning, windstorms can rip through during the late summer, breaking off branches and uprooting trees at their roots. Uprooted older trees might not have the strength to recover, but small trees can be straightened and spiked immediately.
While it’s a good idea to cut off dead branches to avoid creating breeding grounds for diseases and insects, in general, limit any fall pruning. Too much removal of wood can cause sunscald, weak branching habits and sucker growth.

Not a drop to drink

Lack of water is one of the most common causes of tree damage and typically comes on slowly over a period of hot, dry summer months where your trees just didn’t get the water they needed.
Unlike flowers, which wilt after a few days without water, older established trees don’t initially show signs of suffering. But by the end of summer, premature fall color—such as yellow-colored leaves on river birch and poplar trees or brown-colored sycamore leaves—are a good sign that your tree needs a deep watering. Add water to the root zone until the soil is moist to a depth of 6-12 inches.
Yet another symptom of long dry spells or extreme windy conditions is the demise of a tree’s fine feeder roots, which often can’t replenish water as quickly as it’s lost through the foliage. A common result is “leaf scorch,” as evidenced by brown leaf tissue on the edges of leaves and between the main veins.
Broad-leaf deciduous trees are especially susceptible to leaf scorch, so if you’re planning to replenish your yard with these trees next fall, plant them in areas protected from exposure to sun and wind.

Inspecting for insects and disease

If your tree is suffering, the culprit is either abiotic (non-living) or biotic (living). Examples of abiotic factors are those previously discussed—drought, mechanical injury (i.e.: lawn mower attack), or storms. These factors cause damage that won’t spread from plant to plant.
Biotic factors, on the other hand, include pathogens like fungi, viruses and insects. If left untreated, these pathogens can spread from one tree to another.
If you notice wood decay as you inspect your trees, inspect the area carefully. The traditional method for cleaning wood decay is to clean the decay and then add a material such as concrete to fill the space. However, according to North Carolina State University horticulturists, the benefits from filling the cavity are questionable. Concrete filler expands and contracts at a different rate from the tree.
Additionally, a tree’s strength comes from new growth, not from the filler material. Does the cavity contain water? If it has been present for more than one growing season, your tree has likely adjusted. Cover the hollow opening with a piece of tin or window screen filled with plaster that will eventually be covered by the tree’s new growth.
If your prized tree is suffering from damage difficult to pinpoint, consider calling a certified arborist, who is trained to diagnose problems and give advice on treatment. They can also suggest who to call for competent tree services in cases of high branches too dangerous for homeowners to remove. Call your local cooperative extension office to find a certified arborist near you.

Tips for winterizing

After you’ve inspected your trees, the University of Georgia’s Forest Resources department recommends take a few last steps to winterize:

• While fall isn’t the best time to prune your trees, it’s a good idea to remove branches that will touch the ground if loaded with snow or heavy rain.
• Cover the soil beneath one-third to one-half of the tree’s canopy with a thin layer (2-3 inches) of composted organic mulch. Pull the mulch back about 6 inches from the trunk to prevent disease.
• Only fertilize if your soil lacks essential elements. Use nitrogen conservatively, especially under large, mature trees or around newly planted trees.
• If there has been little precipitation (and soils are not frozen), water deeply.

Are your trees ready for winter? Do you have tips for other homeowners on fall tree care? Share your tips—or ask questions— in the comments section below.

 

Sources:

“Abiotic Tree Problems.” By Russ Thompson. Southern Nevada Arborist Group. Accessed September 27, 2010 at http://www.lvsnag.org/pdf/AbioticTreeProblems.pdf.

Complete Guide to Trees & Shrubs. Published 2004 by Meredith Books; Des Moines, Iowa.

“Trees: Damage.” By Erv Evans. Consumer Horticulture, North Carolina State University. Accessed September 26, 2010 at http://www.ces.ncsu.edu/depts/hort/consumer/factsheets/trees-new/text/tree_damage.html.

“Winterizing Trees: Dormant Season Preparations.” By Kim Coder. The University of Georgia Warnell School of Forest Resources. Accessed September 29, 2010 at http://warnell.forestry.uga.edu/service/library/index.php3?docID=127&docHistory%5B%5D=2.