Trees are complex organisms. They consist of many interconnected parts which must all function properly for a tree to be healthy, safe, and attractive. Often, however, these systems break down causing a decline in the health of the plant and an increase in the risk of failure.
The Root System
One of the most overlooked systems of trees is the root system. This is simply because they are not visible like the trunk, limbs and leaves. Roots are often described as a mirror image of the trunk with a strong tap root and side branching from that root. This image is misleading and leads to poor care and abuse of the roots.
The actual root system of most trees is a flat plate of roots which occupy the top 12 inches of the soil. Roots spread out from the tree in a radial fashion near the surface of the soil searching for water and nutrients. Soil oxygen content changes according to the soil structure and moisture content and is the controlling variable for root depth.
The roots which are closest to the tree are heavy, woody roots designed to structurally support the tree. These Buttress Roots do not absorb water or nutrients but function as the foundation for the tree. Smaller roots then grow from these trees, exploring the soil in search of water and nutrients. These roots can extend 1.5 times the height of the tree away from the trunk. From these roots grow the smaller, more fibrous roots which absorb water and nutrients. In an undisturbed environment, roots function correctly with few problems. However, we do not live in an ideal world so many problems arise which affect root health.
Stem Girdling Roots
Stem Girdling Roots are roots which grow around the base of the tree. As the tree grows, these roots grow larger and eventually begin to strangle the vascular system of the tree. These roots block the flow of water, nutrients, and carbohydrates throughout the tree. The lack of nutrients causes dieback of the canopy and root system and eventually the entire tree. This is a common problem for maple trees and trees which were grown in pots which causes the roots to circle around the stem. In addition, excess mulch piled up around the trunk of the tree promotes root growth around the trunk also leading to stem girdling roots.
To prevent Stem Girdling Roots, carefully inspect the roots of new trees and cut or redirect any root which is circling the stem. Remove all mulch or soil piled around the base of the tree. For established trees these roots must be exposed and removed. The process of exposing the roots is known as Root Crown Excavation, a service Big O Tree provides. Our staff uses a tool known as an Air Spade which uses forced air to safely remove the soil around the roots. After removing the soil, the roots are then exposed and any circling roots or stem girdling roots are removed.
Soil Compaction
Another issue that affects the roots of trees is soil compaction. Soil structure contains organic material, minerals, clay, silt, sand, and stones. These components create a structure which allows for spacing between for air, water, roots, and a host of micro and macro organisms, a dynamic community which promotes plant health. When undisturbed, this soil structure and related organisms leave an open, loose soil allowing the roots to easily roam in search of water and nutrients. However, when the soil is compacted, the space between these structures is compressed. This reduces the holding capacity for air and water therefore increasing the difficulty for the roots to grow.
Anything traveling across the ground compacts the soil. Trucks, cars, mowing equipment, and tractors all compact the soil. Foot traffic is also a significant contributing factor to soil compaction. Often, the first sign of soil compaction is the decline of turf grass in areas of high foot traffic. The compacted soil can get as hard as a brick with no pore space left and the soil becomes dead.
Soil compaction can be remediated through some sort of aeration. Core aeration of turf is effective for the upper few inches of the soil but does little for the deeper soil condition. Big O Tree offers a service to help trees with compacted soil. In this process, we use the Air Spade which uses forced air to loosen the soil. Once we loosen the soil, organic material is added and incorporated into the soil to improve and maintain soil structure. This soil aeration and amendment process is vital to the longevity of mature trees.
If your tree is showing signs of decline: limb and branch die back, smaller leaves, reduced new growth, contact Big O Tree to have one of our skilled Arborists inspect and assess your tree. Our Arborists are skilled at diagnosing tree problems and have the knowledge to develop a remediation program.