When doing a tree health assessment, you want to make sure that your tree has a single dominant main stem, or in some cases, for example Birch trees have two dominant stems. The bark should be totally intact with no signs of breakage, cracks or bulges. The base of the tree trunk, also known as the root collar, should flare at the base and radiate away from the dominant stem into the soil. Trees should have a full canopy of leaves with no signs of wrinkling and discoloration. The branches of the tree should spread from the main stem without crossing one another.

Tree Defects

Codominant Stems

When you see two branches that are almost equal size growing side-by-side and squeezed next to each other forming a “u” or a “v” shaped union, this is called Codominant Stems.  Codominant stems prevent the development of proper growth since both stems act as the tree’s main leader. Codominant stems can cause weak branch unions. As these stems of comparable size grow, they squeeze each other. The stems move in te wind and rub, creating a wound that eventually leads to decay and a weakened treeRoot Problems

Root Collar

The root collar on healthy trees flare at the base and the roots spread away from the main stem in the soil.  The structural roots at the base of a tree form its root plate.

girdling roots

Crossing or roots that are circling around the base of the tree is another common root problem. Tree roots grow in the direction they are pointing. Circling and crossing roots will constrict other roots and will eventually slow the water uptake and kill the tree.

CRACKS

Cracks in the trunk or limbs of trees are indicative of unstable and potentially hazardous trees. Cracks can sometimes occur from extreme weather fluctuations, poor closure of wounds or weak branch connections and unions. Both vertical and horizontal cracks may appear. The image on the Left is an example of a shear crack, where the cracks are vertical with the grain of the wood. The image in the right is known as an inrolled crack. This occurs when the tree tries to grow over the vertical crack. This can be potentially dangerous as the included bark prevents the wounds from healing and causing it to spread and enlarge. Horizontal cracks are indicators that wood fibers are being pulled away from each other and occur across the grain.

DECAY

Decay can seriously weaken the structural integrity of a tree. Decay is caused by fungi or bacteria. Fungi usually enters the trees through an open wound that damages the protective bark of the tree. Fungi begins to break down wood within the tree causing it to weaken and eventually break. Visual indicators are typically mushrooms or conks that grow around the areas of decay.  In some trees, particularly Willow, Elm and Cottonwood trees, a bacteria known as Slime Flux can be found. The area of infection looks gray, brown and brassy and in some cases, a slime like substance will run down the bark. Slime Flux is bacteria fermentation of tree tissue and has a foul smell associated with it.

POOR TREE ARCHITECTURE

Trees that are leaning are more prone to failure. Leaning trees could form cracks on the opposite side, bulges in the bark and root balls may start to rise of the ground creating a mound of soil on the opposite side of the lean.