21st Century Arboriculture

Arboriculture in the 21st Century

by Kevin Bassett and Russell Peters

The science of Arboriculture is advancing rapidly as is most every area of science. Our understanding of trees has increased dramatically during the relatively short period (26 years) of our company’s existence. New treatments for improving the health, beauty and safety of trees are coming forward at an ever increasing pace. As part of our commitment to serving our clients, we are continually learning of and evaluating these new treatments and technologies for use in a practical manner for the benefit of our clients and their trees.

Dr. Alex Shigo recently died and his career of over 50 years was dedicated to increasing the knowledge of tree anatomy, physiology and how trees deal with wounding. He studied trees with a chainsaw and a microscope and he was a great educator of our profession.  He always acknowledged that he learned more about trees from Arborists than from any other source. Because of his work, most professional Arborists now know that painting tree wounds has no positive effect on a trees ability to respond to wounds or on the decay process. We now know that pruning limbs and branches at the branch collar is the best and least damaging way to remove a branch or limb.  We now know and understand that tree roots live and grow with associated micro-organisms in a symbiotic manner and that these organisms are vital to tree health. We apply this knowledge in an artful manner daily for the benefit of our clients and their trees.

In years past we became aware of a new idea in Arboriculture that utilized the injection of materials directly into the trunk or roots of a tree. The first use of this technology was in fighting the vascular diseases of trees such as Oak Wilt and Dutch Elm disease. Although this technology is far from a cure all for these diseases, it has become an effective tool for managing these diseases and their spread throughout our communities. Many different systems for injecting these materials have evolved and become commercially available over the last thirty years. Fungicides, insecticides and micro-nutrients have been introduced with varying degrees of success.  Some of these materials have been used to attempt the correction of basic site related problems such Iron deficiency symptoms or Iron Chlorosis. The problem has always been that certain trees are not able to utilize iron that is tied up in the soil due to high soil pH. This issue is true in the Dallas area where high soil pH leads to a variety of problems for  species such as Sweet Gum, Silver Maple, Magnolia & certain species or hybrids of Red Oak. You will notice these trees due to their characteristic yellow leaf color. Recent developments include an injectable material know as ‘Verdur®’. This treatment has shown a great ability to supply the affected trees with Iron and increase the trees ability to synthesize chlorophyll. The result is green, healthy leaves and a healthier tree more well suited to deal with all of the stresses that go with urban life for a tree.  Past injectable treatments for this problem have failed because the material was used up quickly by the tree. As a result, the tree would have to be injected on an annual basis to maintain consistent results. In effect, this created a large number of small wounds at the base of the tree and these wounds became entrance courts for decay organisms. The cure was in effect, as bad or worse than the disease. With this in mind, our efforts to help address this specific problem has been to provide the nutrients needed through the soil via our deep root invigoration programs. We add sulfur to help lower the soil pH and a chelated form of iron that is readily available to the tree. This treatment helps many of the trees affected by this problem, but this approach requires frequent repeated treatments to achieve and maintain a good result. Additionally, problems arise when a portion of the root area is not accessible for treatment application. In these cases, part of the tree becomes green and another portion has no improvement. We are hopeful that ‘Verdur®’ will become another effective tool that can be used in conjunction with our normal treatment that will help with this particular problem. Due to the fact that yellow leaves on trees can be for a number of different reasons, it is important that any of these treat­ments be recommended only by your Arborist. As always, Arboricultural treatments usually involve a trade off. Yes the injection of ‘Verdur®’ can help with the yellow leaves on your trees but there is still the wounding aspect as a concern. The positive aspect about this material over others is the fact that this material will remain in the tree supplying the needed nutrients for up to 3 years. This makes the wounding aspect less of a concern and this approach to iron deficiency is one that you may see recommended by your Arborist in the near future.

Despite the gains in science, it remains true that the best trees for our area are native trees and those species that are adaptable and have proven their ability to thrive in the rigorous conditions present in our area. We now have another tool that when applied wisely can be helpful. As a client of Arborilogical Services, Inc., you can depend on our vigilant efforts to stay on top of the ever changing advancements in the science of Arboriculture, and the judgment of when and where these new treatments and technologies are prudent.  It is important to note that despite all of these advancements, Arboriculture remains an art as well as a science.

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