Updated: Sep 11, 2020
Written by: Fred Hoppe, Board Certified Master Arborist WI-0556B, Certified Tree Care Safety Professional 00036, and ISA Qualified Tree Risk Assessor
Does something just not look right about your tree as we head into fall? Are the leaves on your tree starting to turn a little yellow? Are the veins of the leaves the only portion that is green? Are the leaves falling off prematurely? Are these signs happening on a isolated branch or the entire tree? If any or all of theses symptoms are present, there is a high likelihood of your tree being under stress and tapping into its stored energy reserves.
There are a number of common issues trees in southeastern Wisconsin face that lead to stress:
Chlorosis is a very common nutritional disorder in many trees in our area of Wisconsin that causes lack of chlorophyl production. Some of the most likely trees to have chlorosis in our area include silver maple, red maple, white oak, paper birch, and river birch.
Scab disease is caused by a fungus that infects both leaves and fruit. Scabby fruit are often unfit for eating. Infected leaves have olive green to brown spots. Leaves with many leaf spots turn yellow and fall off early. Scab-susceptible trees are in the Rosaceae family such as apple, crabapple, and pear.
Fire blight, named for the scorched appearance of infected leaves, is a bacterial disease found on apples, pears and other members of the rose family.
These are just a few of issues that commonly affect trees in our area. In late summer and early fall, the symptoms of these biotic and abiotic disorders show up. At this point of the season, foliar applications to treat these issues are typically no longer an option due to being so late in the season and therefore not effective. The question is, what can we do at this stage of the season to help our trees?
Fortunately there are good options to improve the health of trees facing these and other issues.
Soil injection fertilization with added micronutrients can help increase the amount of iron and other needed micronutrients in the soil. A fertilization program's goal is creating a healthy soil network ready for a tree's root system to utilize.
Trees treated with paclobutrazol, which is an active ingredient of growth regulators, show an increased production of fibrous roots. This helps the plants by expanding the area of soil the plants can pull water, minerals, and other resources from. The treatment is applied to soil and may be applied anytime that the ground is not frozen or saturated with water. This treatment pairs well with fertilization. The fertilizer creates the healthy soil and the growth regulator creates a healthier root system to utilize that healthy soil.
The primary goal is to create a suitable soil environment that promotes fibrous root growth resulting in greater capacity to acquire water and nutrients from urban soils and a healthy, more vigorous tree. Compressed air is used to reduce soil compaction, increase oxygen in the soil, and incorporate organic matter into existing soils. This treatment increases the likelihood of improving the soil structure and establishing a beneficial environment for tree root growth.
There's still time to improve the health of your trees with these treatments. Give our certified arborists a call today at 414.257.2111 to schedule a tree inspection in your yard.