Common Urban Tree Problems
Topping
Topping is known as perhaps the most harmful, yet also common, tree pruning practice. Topping trees often leads to stubs and wounds that the tree will be unable to close properly. People feel that topping trees is a way to reduce the overall risk of a large tree, but in the long run, a topped tree is likely to offer more risk than before. Leaves are the food producers of a tree, removing a large percentage of the crown could potentially starve a tree to death. Topping trees also causes trees to become stressed, which often lead to infestation by insects and diseases. To maintain a good tree structure and health, proper tree pruning methods are essential.
Stem Girdling Roots (SGR)
Urban environments can be a difficult place for a tree to thrive. Tree roots are the main source for water and nutrient uptake. Often, trees are planted too deeply which cause major root problems. Stem Girdling Roots (SGR) is defined as roots that begin to grow around the main stem of the tree and cut off or restrict the movement of water, plant nutrients and stored food reserves. In order to minimize SGR, trees should be planted properly with a visible root flare at soil level.
Improper Mulching
Mulch provides many benefits for tree health. Mulching trees helps maintain soil moisture, reduce soil compaction, control weeds, and provides an aesthetically pleasing view. Applying large piles of much at the base of a tree is often referred to as “volcano mulching”. Volcano mulching is harmful for tree health due to the development of poor root structure and additional problems. Proper mulching is essential for tree health and root development. When mulch is applied, the recommended depth is 2-4” with the mulch being pulled away from the root flare.
Chlorosis
Chlorosis is the yellowing of leaves caused by an insufficient amount of chlorophyll. When soil is alkaline or slightly acidic (pH above 6.5) micronutrients iron, zinc, and manganese are restricted during uptake causing the plant to decline. In Central Illinois, Pin Oaks are very susceptible because of their need for micronutrients in relation to high soil pH which limits proper uptake. In order to ensure accurate identification, foliage and soil analysis is recommended before treatment. Once the problem is identified then action should be taken immediately. Pin oaks suffering from severe chlorosis may not respond to any treatment and eventually die.
Oak Wilt
Oak wilt is caused by a fungus called Ceratocystis fagacearum; it is responsible for killing large numbers of oaks annually in Illinois. Oaks are by far one of the most valued shade trees in the United States. Red oaks and Pin Oaks are highly susceptible by the oak wilt fungus. Oak wilt is easily identified in red oaks by the fast wilting of affected trees. After symptoms first appear, a red oak will generally wilt completely in two to six weeks. The trees wilt from the top of the crown down and individual leaves wilt and turn brown. The disease is spread through root grafts as well an insect vectors. Trees showing oak wilt symptoms should be managed immediately.
Rhizosphaera Needle Cast
Rhizosphaera Needle Cast is moisture driven disease that is common in spruce trees. The fungus is present on the needles causing nearby trees to be infected. Rhizosphaera starts in the low interior branches moving towards the top causing branch dieback and leaving the tree unsightly. Trees showing symptoms should be cared for to prevent the spread of disease to surrounding trees. Severely infected trees may never recover from Rhizosphaera. Our goal as professionals is to get your trees on a preventative maintenance schedule and reduce the risk of unwanted problems in the landscape.
Japanese Beetles
Japanese beetles are one of the most common insect problems among the urban tree population. Grubs feed on the roots of turfgrass and adults feed on the foliage of more than 300 plant species. The beetles have a one year life cycle. In late June, the first adults emerge with most present in July and August. Japanese beetles are chewing insects that destroy flowers, leaves, and fruit of a wide variety of plants. Feeding occurs at the top of many trees and moves downward making eradication difficult for homeowners.
