Nitrogen "Overdose" of trees

Mark Webber • July 16, 2018

Too much of a good thing and kill your tree!

The months of July and August are a time when plants can struggle and may be in decline. Many plant owner and managers may notice that valuable plants are exhibiting symptoms and signs of chlorosis. Chlorosis is abnormal reduction or loss of the normal green coloration of leaves of plants, typically caused by nutrient deficiency or by disease or lack of light and by herbicide exposure.

However, one of the greatest mistakes that I see, is when tree owners and professional diagnose a plants issue to be a "xyz" deficiency without performing adequate testing to determine the root cause of the problem. Keep in mind plants utilize and need varied amounts of minerals to conduct vital life process. The only true measure of what a plant really needs is by performing a soil and a foliar test. Foliar test is a plant tissue analysis, which measures nutrient levels within plants tissue and identifies nutrient deficiencies and toxicities of 11 mineral salts and are provided in as % or ppm(parts per billion) basis. Recently, I read a test result for a client and that Nitrogen levels inside the subject Oak tree that were at 8.31% of the necessary range of 2.0-4.0%. Therefore, the tree had a Nitrogen overdose and the only source was from the lawn care products being applied near the subject tree. More so, tree health can be severely damaged by overdose treatments as well as under applied treatments.

Keep in mind a tree recycle approximately 60-70% of their Nitrogen needs from a year to year basis. Living tree systems must utilize fixed or reduced nitrogen (energized N) for incorporation into amino acids, nucleic acids, and proteins. Recycled nitrogen must be factored into how much to feed a tree or the lawn that is nearby. Reduced nitrogen has been energized and made chemically reactive by addition of electrons. Reduced nitrogen is electron-dense and viable as a biological building component or a reaction coupler inside a tree. Reduction, fixation, or a change in oxidation states, is essential for nitrogen use by a tree. The amount of inorganic nitrogen present in soil has a direct effect on tree health and growth. At decreasing concentrations, beginning well before visual symptoms are present (because of internal recycling and reallocation of nitrogen), is nitrogen deficiency.

At high nitrogen concentrations, toxicity and physiological dysfunction can be problems. There is an intermediate zone of moderate nitrogen concentrations where tree health and growth is “adequate” for sustained growth. This adequate zone is the target for management activities. Trees attempt to balance shoot mass and photosynthesis rates against root mass and nitrogen uptake. A tree will adjust living mass of roots or shoots to correct any deficiency in photosynthesis rates or nitrogen uptake rates. Carbohydrate shortages and/or nitrogen increases will initiate more shoots —nitrogen shortages and/or carbohydrate increases will initiate more roots.
Prescribing N

Supplemental nitrogen enrichment should be treated as a fined-tuned, carefully considered, constantly modified, whole tree prescription process. The whole tree wins or loses with changing reactions of one major organ or resource. Nitrogen prescription involves prudent and reasonable treatments carried out in a timely manner without site and tree damage.

The nitrogen dose provided by supplemental additions, and its timing, are part of a comprehensive management prescription that should vary primarily by ecological season of the year, a tree’s ability to successfully and effectively utilize nitrogen additions, and by the life stage a tree. These considerations deal with successful capture and use of nitrogen by a tree as it grows, and with minimizing environmental impacts to untargeted systems (i.e. nitrogen to weeds, streams, and soils).
Whole tree reactions to significantly increased nitrogen levels:
— Increased shoot size.
— More foliage growth stimulated.
— Photosynthesis & stomates sensitive to water stress.
— Lengthened growing season.
— Increased amino-nitrogen content.
— Decreased starch in whole tree.
— Increased pest effectiveness.
— Decreased defensive materials produced.
— Carbon allocation to fine roots delayed.
— Decreased carbon allocation to the roots.
— Root carbon storage reduced.
— Root sugar concentrations increase.
— Decreased root reactivity to damage and stress.
— Poorer cold tolerance in root system.
— Encourages starch use, not photosynthesis increase

It is very likely the high levels of nitrogen combined with the elevated pH will also cause for decrease in uptake of Magnesium and Phosphorus and will directly affect the trees health. The bottom line is when nitrogen sources like from lawn care applications are made they can have dramatic effects of tree health and well being.

So don't guess, soil & folar test and apply fertilizer products to your lawn, plants and trees based on those results!





By Mark Webber March 8, 2023
Often the public thinks that they can pick and place plants in their landscape like furniture. Before you plant anything do a investigation of the zone hardness, soils and other factors. It's always better to plan and investigate before you plant. Work with a qualified, certified and registered Arborist for the best results. https://www.webberlandscaping.com/landscape-designer
By Mark Webber August 31, 2021
The fall armyworm (Spodoptera frugiperda) annually migrates northward, invading much of the continental United States and Canada. Many lawns in the month of August of 2021 are being eaten to death in the greater Dayton, Ohio area. The larval (caterpillar) stage of the fall armyworm moth can cause severe damage to lawns. In summer, the moths lay clusters of eggs in cotton-like, greenish-white masses on structures (houses, mailboxes, fences, signs, etc.), shrubs and trees, and the newly hatched larvae drop down to the ground and “march” like an army to feed on the closest grass. While the larvae are still small, damage may not be readily apparent. But when they reach their full size (about 1-1/2” long), they can eat the grass down to the soil. Significant infestations can defoliate a lawn entirely. Lush green grass is the fall armyworm’s preferred food, so irrigated lawns of any type (warm- or cool-season) are at most risk. So are newly laid sod and newly seeded or overseeded lawns since these must be kept moist/irrigated until the new grass establishes roots. Controlling fall armyworms is difficult since several generations can occur in one summer-through-fall season. Products that contain carbaryl (such as Sevin) or pyrethroids will be most effective while the larvae are still small. Mowing the turf and light irrigation before treatment can increase control. Repeat treatments may be necessary. Resources: https://turf.cals.cornell.edu/pests-and-weeds/insect-management/#caterpillars Potter, D.A. and S.K. Braman. 1991. Ecology and management of turfgrass insects. Annu. Rev. Entomol. 36:383–406.
By Mark Webber April 24, 2021
By Mark Webber March 13, 2021
Many homes are often constructed or renovated near existing trees to take advantage of their aesthetic and environmental value. Unfortunately, the processes involved with construction can be deadly to nearby trees. Recently we were assigned by a property owner to determine the health and condition of three trees commonly known as Silver Maple( Acer saccharinum). The property owner had recently purchased the property and had no information about the subject trees' prior treatment. The client was advised that we needed to conduct a starch test of each subject tree's condition. Starch tests provide the inspecting arborist a measure of the carbohydrate capacity of the tree in question. All green plants produce sugar (energy)in their leaves during photosynthesis. The sugar is then either used in the leaves as an energy source for the growth or production of other essential materials or transported via the phloem (inner bark) to other parts of the tree. The sugar that is not used immediately is linked together in long chains to create starch. Starch is the product the tree uses to store much of its energy reserves. By staining wood for starch, the level of the tree's energy reserves can be estimated. This information is beneficial when making a diagnosis of the tree's condition. Our testing of these three trees determined that they were collective in poor condition since the starch tested yielded light color wood. If a tree is in good condition related to carbohydrate reserves, then the starch test will yield a dark-colored wood when exposed to the iodine mixture. We discovered that these three trees had been severely injured ten years prior due to construction injury due to sidewalks, street curb, and underground pipe installation after reviewing our historical files and data. These subject trees have poor growth rates, limb loss, decay, and are becoming a hazard to the public and property. The necessary take-home lesson is that trees are often the victim of people pressure disease(PPD). With good arboricultural and horticultural advice, PPD can be avoided if the tree's owner is willing to follow a qualified arborist's advice and guidance when managing their trees. To learn how to manage trees that may be exposed to construction injury click here .
By Mark Webber March 6, 2021
Learn how Mark Webber's Landscaping Company is saving Century-Old Oak's
By Mark A. Webber August 29, 2020
By Mark Webber August 1, 2020
In the growing season of 2020, I have witnessed an increasing frequency of trees being injured and damaged by the improper applications of pesticides targeting weeds in lawns. For the most part, these pesticides are herbicides that are commonly known as synthetic auxin. Synthetic auxin herbicides are used often on residential and commercial properties for broadleaf weed control. Trees and plants damaged by these pesticides often have these symptoms: Twisted leaves Downward cupping on leaves Narrow, strap-like leaves on the youngest growth Synthetic auxin herbicides are products commonly known as 2,4-D, Dicamba, Weed Be Gone, and others. These materials are manufactured to mimic naturally occurring plant hormones. There are five types of hormones in plants that include auxins. Plant hormones are triggering devices in plants. Plant hormones are triggering mechanisms that cause growth, leaf drop/formation, root expansion, flower bud formation, and other plant processes. In the case of herbicides that contain synthetic auxins, they mimic naturally occurring auxins that result in uncontrolled cell division. The uncontrolled cell division causes plants like broadleaf weeds and or trees certain death or severe damage. Many cases, the herbicides with synthetic auxins are indiscriminate broadleaf plant killers, especially if your tree has roots growing under your grassy lawn. Research has shown that trees have a massive root system that extends well beyond the tree's outer branches stretches over your yard. The root system of the trees in your lawn is made up of a vast network of the large, medium, and hair sized roots that are directly under the grass and weeds. Tree roots are not covered by bark, but are covered by the epidermis and have a multitude of root hairs. The roots of trees readily absorb water, nutrients, and pesticides. Roots of trees are not structured internally on a cellular level to filter out, so to speak harmful substances like herbicides containing synthetic auxins. So, even though you can't see any roots above your lawn from your trees, they are beneath your feet. The roots of your trees are just under the grass and the weeds. The roots of trees below the turf and weeds will readily absorb what's applied to the above-ground landscape. The majority of herbicides containing synthetic auxins forewarn users not to apply these products were tree roots exist. The label of these products is the legal requirements on how the product is to be used. The label of any pesticides is the law. If the applicator fails to follow the label, then that person is guilty of breaking the law. However, these label warnings are often ignored when the label states, "do not apply where tree roots exist." The failure to follow the labeling law results in damage, decline, and, in some cases, the death of trees. Herbicide injured trees can be killed and, in other cases, are more susceptible to diseases and insects and future decline. The bottom line is don't use herbicides that forewarn you not use them near trees and their root systems. If do you suspect that your trees have been exposed to herbicides, you should contact a qualified arborist for an inspection to investigate if your trees have been exposed to pesticides.
By Mark Webber March 2, 2019
Photo Source (Tree Dictionary) This week I spent some time helping the team at Mark Webber's Landscaping conduct a tree risk assessment of a very large Ash tree. After the Ash inspection, I then inspected a number of other trees on the subject landscape. The property owner had unfortunately had her trees been mistreated by improper pruning. The term “seal,” rather than “heal,” is used to describe tree wound closure, since the wound still exists inside the tree even after it no longer shows on the outside. A properly pruned tree will create a better tree; however, a poorly pruned tree will result in a deteriorated condition. Trees have a natural defense response to wounds and pruning cuts. They form four types of walls to compartmentalize the area thus preventing the spread of decay organisms. However, if you prune too much from a tree, it will not have the energy resources to have the energy to compartmentalize. Proper pruning techniques and timing are critical to long-term tree health. The most important principle to remember is that each cut has the potential to change the tree considerably. Tree pruning needs to be well thought out and based upon what science and the Best Practices of the International Society of Arboriculture. In this case, the client's trees were excessively pruned by removing all of the subject inner branches resulting in a tree branch that looks like a lions tail. Lion's tail pruning creates tree branches that are likely to fail under normal weather conditions. In the case, the recommendation to this client was to do nothing or not to prune the subject trees for at least the next 6-9 years. Pruning Dose As a tree gets older the more difficult, it becomes for the plant to manage excess cuts. (See Chart/photograph above) When trees are young [Y] great amounts of symplast maintaining wood [L] can be removed. Symplastless wood is a term that is lucid to describe a tree or piece of wood or tree part that no longer maintains a symplast. As the tree matures [M] less symplast maintaining wood should be removed, and symplastless wood removal should increase [D]. As the tree approaches over maturity [OM] very little symplast maintaining wood [L] wood should be removed, and great amounts of symplastless wood [D] should be removed. Bottom Line If too many tree branches are removed or if the cuts are too large in older trees will result in further deterioration to the subject tree that may result in the loss of your valuable tree. You should use only Certified Arborist to make decisions about how to best manage your trees. Here are some important tips to follow for better trees: • Start training trees with pruning while they are young and newly established. • Minimize the number of live branches removed at any one time. • Use proper cuts. Watch the branch collar and/or branch bark ridge. • Pruning dose should be determined by overall tree health. • Reduce live-tissue pruning during times of drought. • Remove smaller branches rather than larger branches. • Do not top trees for any reason (heading cuts). • Prune when trees are biologically active to expedite wound sealing. • Do not use tree wound dressings. References http://www.treedictionary.com/DICT2003/tree_pruning/dose/chart.html Tree Pruning Essentials. Lindsey Purcell. Purdue University.2015 McKenzie, R. 2008. What’s Wrong with Topping Trees?, FNR-FAQ-14-W. Purdue University Cooperative Extension, West Lafayette, Ind., USA.
By Mark Webber February 17, 2019
Trees are commonly injured. These injuries can cause structural defects if the tree does not successfully manage these damages by blocking water, bacteria and fungi.
By Mark Webber February 3, 2019
Frost Cracks in trees and how to prevent and manage.
Show More
Share by: