Arborguard Newsletter

Trees Suffer During Prolonged Drought

Drought continues to straddle Georgia. But, if you support your trees with a proactive plan where you monitor for pests and disease, and respond to warning signs, they are more likely to survive. Silent Suffering: A tree's first damage from drought occurs beneath the soil line in the form of root damage, long before any outward signs of trouble. After a tree's unsuccessful attempts to conserve water by closing stomates, feeder roots die back, sometimes so drastically that the tree is unable to take up enough water to support itself. In the worst case, a healthy looking tree collapses without much warning. More often, though, the signs of stress are much less dramatic. "Radial growth slows," explains Peter Gerstenberger, senior advisor with the Tree Care Industry Association. "Leaves are undersized and may wilt, yellow, curl, or crinkle, will be marginally scorched, or even turn brown and fall. Emergent shoots are short. In an effort to right the imbalance caused by root-loss, crown dieback or a general thinning of the canopy occurs."

That's when "opportunistic" pests make their move. Boring insects are thought to be drawn by the odors and acoustic signals of stressed trees. The sound of water columns breaking cues the borer to invade the tree and lay eggs. Gerstenberger recommends taking preventative action by applying treatment by spray or injection to protect prized or important trees from borers because, "by the time we realize the tree is stressed, it's been heavily riddled and girdled."

Another danger to stressed trees is fungus, which makes initial contact with surface roots. Gerstenberger notes that when a chemical change in the tree signals a weakened state, the fungus penetrates the bark, wood, and cambial zone with fan-like, leathery clumps, cutting off the water supply to the tree.

While all trees are at risk during long periods of drought, some are more prone to its effects. New transplants are highly vulnerable to drought stress, and supplemental watering for the first few years of establishment is necessary, to the extent that it's allowed. But even mature trees are suffering.

Watering trees deeply with soaker hoses or irrigation systems - as opposed to brief, surface watering - helps sustain trees. But it's very difficult to do much for a large tree because of the massive amounts of water it needs. With so many trees affected, Gerstenberger recommends watering only those trees that you can help. How much water a home landscape needs depends upon its soil, sun and shade exposure, plant types, irrigation system and local climate. How much water trees require depends upon the type of tree. Applying the right amount of water, based on the local weather and the tree's actual need, is the key to using water efficiently.

Drought exacerbates matters for trees already under stress, like those on dry slopes, surrounded by pavement, or improperly planted. In landscape situations, consider taking action, like moving smaller trees to a better location, alleviating compaction. Pine needles or a two- to three- inch layer of compost will help trees in maintaining moisture. The after effects of the current drought will likely ripple for the next three to five years, with the strongest trees surviving. Trees have developed their own mechanisms for coping with these cycles, but some trees are on the brink of survival and could go either way. If it means the difference between keeping a tree around for your lifetime or losing it in the next five years," Gerstenberger says, "it's worth doing something about."

During this time of watering restrictions it is important to water the root zone of your trees. Your garden hose can deliver about 5 gallons of water per minute.

Drought is tough on trees. Atlanta needs 1 inch of rain per week under normal conditions for vegetation to survive. After five months, we should have had 20 inches of rain. Instead we are now 12 inches below normal for the year. Worse yet, this is a continuation of a prolonged multi-year period of dry conditions. The deficit will take a terrible toll on our trees. Trees are over 80% water and just like us, they can only survive so long without water. We can't make it rain and we are restricted with watering so what can be done to help trees survive?

Arborguard has developed a line of organic soil therapy products over the past 26 years designed to hold water in the soil, making it available to refresh wilting root hairs and sterile soils.

Arborgrow® contains a carefully blended mix of organic humates, sea kelp, beneficial microorganisms, nutrients, buffers, and supplements that improve water holding capacity by 200%. It is pressure injected into depleted soils, which aids in aeration and penetration of surface water as well. The combined effect can make the difference between healthy or declining trees, which are susceptible to borers, disease or even mortality. Please call us at 404.299.5555 and together we can keep Atlanta's trees alive!

Maturing hemlock wooly adelgids soon after coming out of dormancy. (R. Childs)

The Woolly’s Have Arrived

Hemlock Woolly Adelgids are now starting to show up in Atlanta yards. The Woolly Adelgids invaded the United States in the 1920's when they were somehow imported from Japan. Since then they have spread rapidly. Hemlock trees in the southern Appalachians are under attack and if nothing is done, we will lose most or all of these magnificent trees from the region, including the thousands of acres of old-growth in the Smokies.

Woolly Adelgid's cause Hemlock trees to become weak and eventually die. Infested trees first begin to look thin with a lighter green color. This happens because the insects feed by sucking sap from twigs and foliage causing the tree to become weak and the needles to fall off. A serious infestation can defoliate a tree in as little as one year. Look for white globular masses of cottony/waxy tufts on bark, foliage, and twigs. Check the base of needles and small twigs especially close. The tufts that you are looking for are actually protective covers for the adelgids body that remain in place throughout their lifetime. If you see any of these sign on your Hemlocks please call us for an inspection. Treatment options are available for Hemlocks growing on your property. We are here to help. For more information on saving the Hemlocks visit www.saveourhemlocks.org.

Ambrosia Beetle courtesy University of Georgia

Ambrosia Beetle Alert

Reports of Asian and native ambrosia beetles have been on the rise this growing season. The reason for the increase is still unclear. In many cases, ambrosia beetles are secondary insects that attack trees weakened by construction or drought. However, seemingly healthy trees have been infested, even after periods of adequate rainfall.

Identify the Pest

Identifying the species of ambrosia beetle is the first step in determining the method of control. The Asian ambrosia beetle will attack almost any broadleaf tree or shrub. A tell-tale sign is the long strands of frass that look like toothpicks protruding from the bark.

Other species of ambrosia beetle are more selective about their hosts, and will leave piles of whitish boring dust around the tree's base. Wilting may also occur if the stem is girdled.

Adult beetles bore into the woody stem of the plant and excavate tunnels to lay eggs. If girdling does not kill the tree, the fungus that the female deposits in the wood clogs the vascular system as the tree grows. The beetle gets its name from this fungus which is the "ambrosia" for the larvae. Almost the entire lifecycle of the beetle is spent inside the plant. The infestation is usually always fatal to the tree. It's important to catch and remove infested trees quickly to prevent spreading.

Treatments are Limited

Once a tree is attacked, insecticides will usually not help. A trunk injection will kill the beetles, but there is no guarantee of the tree's survivability. In most cases, the infested tree or limb should be removed and destroyed. Adult beetles are active late Spring to early Fall. A preventive spray can be applied to help protect trees during the growing season; however, there are no guarantees. Keeping a tree healthy is generally the best prevention. Vitality and watering issues can be addressed at any time of year.

Our ISA certified arborist can identify ambrosia beetles and/or prescribe a tree care program to help reduce the risk of these pests, and provide nutrients to your trees to keep them strong and healthy.

About Arborguard

Arborguard was founded in 1981 to provide quality tree care and exemplary service to our customers. Urban life disrupts the delicate balance of nature. Experience has enabled us to formulate a basic care program that helps your trees thrive in their urban environment.

As tree care specialists, we know better than anyone what trees need: sea kelp, mycorrhizae and other soil additives are some of the natural supplements we use to make life easier for trees. Selective pruning enhances natural branch structure. Cabling and lightning protection systems help prevent damage by natural forces. Disease and insect diagnosis and treatment are vital to reducing tree stress. Our goal is to provide a custom and effective tree management plan that results in healthy, safe and beautiful trees.

Our staff of highly skilled, technical professionals includes ISA certified arborists, degreed foresters, and industry certified tree care specialists. Employees attend industry-sponsored conferences, workshops and seminars to stay informed of the latest issues.

Regular in-house training ensures a high level of skill and familiarity with the current standards in tree care. We are a "Certified Drug-Free Workplace," and proud to have earned one of the industry's highest safety records. In 2007 we were one of the first tree companies in the Southeast to receive Accreditation by the Tree Care Industry Association (TCIA).

Because we believe in our work, we offer this guarantee:
Don't pay until you're satisfied that we delivered what we promised.

Our commitment has always been, and will continue towards excellence in all that we do.

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