The main reasons for mulching are:
- Prevent temperature extremes
- Prevent erosion
- Improve soil quality with nutrients and water attention
Mulching in the area of the tree’s root zone is the best condition for the trees on your property. Unlike grass or other plants growing in this area, a mulch layer somewhat mimics the conditions of a forest floor where there is compostable material covering the soil. This layer provides protection for the soil underneath from extreme temperature changes, aids in the absorption of water, and provides nutrients as the material breaks down.
In contrast, turf in this area tends to do the opposite. The shallow grass roots compete with tree roots for water and nutrients and tend to create an absorption barrier in the soil that can render the deeper zone inhospitable to root growth. Generally speaking, the larger you can make your mulch ring, the better the health of the tree’s root system.
Remember that a tree’s roots can reach out much further than a tree’s canopy.
The optimum depth of a mulch layer is two to three inches. Any more than this, and there can be an absorption barrier that prevents water saturation. Mounding mulch in this area can lead to poor root structure and can lead to further problems for your tree.
So that is how you properly apply mulching.