Below the surface of the soil lies a complex soil food web we will likely never see. Without it, much of the plant life we enjoy would not be able to exist. The soil food web consists of many organisms that are beneficial to the health of the soil. This beneficial web is plentiful in an undisturbed forest setting, but can be diminished or lacking in some of the soils we have around our homes where our trees are trying to exist.
Many practices done to soils can disturb this fragile soil food web. Things like compacting the soil, overwatering, lawn treatments, removal of leaves and small branches, etc. can have major impacts on this fragile web. A healthy soil will need organisms like nematodes, beneficial fungi, bacteria, protozoa, arthropods, and certain other animals in order to maintain a favorable growing environment. These organisms play a critical role in nutrient cycling. Nutrient cycling is the process whereby plant materials are broken down into usable nutrients for plants to carry on life.
The soil food web also creates beneficial soil structures for trees. Soils are much more complex than just a mixture of sand, silt and clay. It is also made up of soil spaces and many other physical structures that allow root growth and expansion.
What does this all mean? It means that we need to do what we can to maintain this diversity of life underground in order to help our trees. Culturally we can do things like mulching (with no weed barrier!) to introduce organic matter, which is a building block for the life underground. If mulching is not preferred, other options exist like composting. Topdressing with composted organic matter under the crown of a tree is a good way to introduce organic matter into the soil. Using soil injected compost teas is another great way to help enrich the soil environment.
Other soil enhancements will benefit soil health as well. Mycorrhizae treatments will help to reintroduce beneficial soil fungi that trees use to increase their water and nutrient uptake. This mutual relationship can be the difference between a tree surviving a major drought, like we experienced recently, or not. Root biostimulants and fertilizer will also help a tree recover from stresses like drought.
The soil is a complex living structure that cycles the nutrients that trees need to grow strong and healthy. Doing whatever we can to enhance this soil food web will improve the health and beauty of the trees in our landscapes. If you feel that your trees are in need of a little extra tender loving care, please be sure to get in touch with your Certified Arborists at Wachtel Tree Science.