Those who cherish trees may not be aware that over eighty percent of the root system of a tree occupies a zone about one foot below the surface of the soil where sufficient oxygen necessary for the tree to survive remains.
The Critical Root Zone
The critical root zone (CRZ) of a tree, which is also called the "tree protection zone," is often defined as an imaginary circle on the ground that corresponds with the "dripline" of the tree. The dripline of a tree is where the greatest extent of a tree’s branches end. For narrow-crowned trees the dripline distance should be expanded to insure that the critical tree roots will be protected
Your tree critical root zone should be protected and is just as important for tree health as fertilization, protection from pests and trunk damage. Vertical mulch along the edge of the CRZ is one way to insure tree health and well worth the investment.
Critical Root Zone. Photo Credit: Athens-Clarke County Community Tree Program, Georgia
The soil in that zone, under the best conditions, consists of half solids and half pore space with contains water and air. A common problem facing tree roots is soil compaction which occurs when high volume of foot or vehicular traffic, or construction machinery exerts downward compacting pressure on the soil beneath.
The soil loses the ability to transport water and oxygen to the root system when the small "feeder" roots at the surface of the soil are crushed. Soil compaction causes an unhealthy imbalance in the tree.
Heavy equipment, particularly construction equipment, can crush the shallow roots of even the largest trees. By limiting the air and water supply to a tree's roots, soil compaction reduces the available spore space.
Without adequate tree root hydration which is vital to healthy tree growth, as well as stress related to an absence of free oxygen, leads over time to a gradual decline in the health of a tree.
Symptoms – Soil Compaction
- Meager leaf growth
- Branches and foliage dying from the tips or roots backward
- Reduction in size and number of leaves
- Poor response to adequate tree care
- Environmental stress and pest problem vulnerability
Solution – Vertical Mulching
For a tree that is looking unhealthy or worn out, vertical mulching might prove to be the exact solution it needs by encouraging healthy root growth.
Vertical mulching is a technique used to assist in alleviating soil compaction within critical root zones of trees. It reduces damage from excessive water by allowing necessary aeration during wet periods and sub-soil water penetration during dry periods. The technique also aids greatly in promoting the formation of fine feeder roots.
Specialized tools create holes in a grid pattern across the root zone of a tree affected by soil compaction. Organic material like mulch and rich compost is then placed into the holes, after which a layer of fresh mulch is spread over the entire area.
Vertical mulching, a time tested method of overcoming the stress trees face in unnatural environments that we force trees to grow under, which creates cores of rich "top soil" down past the grass roots and into the soil area where roots can take advantage of them.
Advantages of Vertical Mulching
The process of vertical mulching can accomplish several simultaneous goals for the roots of a tree.
- It helps to aerate soil right where roots are located.
- It frees up more room in the soil for the two most critically important ingredients for the production of healthy roots: water and oxygen.
- It helps to inject additional organic material directly into the soil in and around the root system. These materials break down in the soil, providing sustenance for micro-organisms that are beneficial to the health of a tree, as well as creating greater root aeration which is important for the nutritional requirements of a tree.
- Promotes of water penetration to the subsoil during dry weather periods.
- Promotes of natural aeration during wet weather periods.
- Minimizes of root damage due to excess water.
- Formation of greater a number of feeder roots.
Property owners can reap remarkable benefits from the simple processes of vertical mulching. Arborist Now offers efficient and safe s vertical mulching services for residential and commercial properties throughout the Greater San Francisco Bay Area. Arborist Now’s team of certified arborists and landscape professionals can also perform a full range of tree care services in Marin County and landscape maintenance services, such as lawn maintenance, tree pruning, tree planting, and irrigation installation. Contact Arborist Now for more information, or go online to request a free consultation.