One of the most difficult and common challenges in our urban environment for trees is soil compaction. Many areas have hardly any topsoil at all due to years of development and this in addition to foot traffic and vehicular traffic compound the problem.
Soil compaction reduces water infiltration into the soil, reduces the area for fine root growth, poor aeration, and on and on. The impact then leads to stress for the tree and making it susceptible to other insect and disease problems. As a result, it is common to see trees struggle during the growing season with small leaf growth, thinned out canopies, and then early season fall colors.
There are multiple ways that this issue can be addressed which include landscape design, layout, and treatment applications. One treatment application that can make a difference is vertical mulching. This application utilizes compressed air using an air spade to create holes throughout the critical root zone (CRZ) of the tree. These holes then have organic materials such as leaf mulch injected to help add organic matter to the soil. This application helps to reduce the compaction, aerate the soil, and inject more organic materials to the soil which are the building blocks of new soil. Extreme cases of compaction may require a complete root collar excavation which is a bit more extensive than simply vertical mulching.
To learn more about soil impaction and its impact on trees, check out this article written by Lindsey Purcell from Purdue University.