After a severe windstorm it is common to see trees that have fallen or ones that look unstable.
While the wind does the visual and lasting damage, it is likely that the tree itself was in poor condition before the storm.
Be proactive and exam trees that are close to buildings on a regular basis. If the tree is weak it should be removed before it falls, creating thousands of dollars worth of damage.
There are seven main factors to look for that indicate a tree is in poor health: deadwood, cracks, weak unions, decay, cankers, roots, and poor structure.
Dead wood is easy to spot especially in the summer as the empty branches are very visible.
During the winter months deadwood can be spotted if it has lost or is loosing bark. Dead branches on the top (or crown) of the tree need to be removed before they fall. While dead branches are often an indication that the tree should be removed it isn’t always the case.
Look for other indicators before removing the tree. Check for cracks in the trunk of the tree. These can form for many reasons many of which are not a reason to remove the tree.
A healthy tree will start to form a callus to close the crack. If the tree is not healthy the crack will become deeper as opposed to healing. Deep cracks with a leaning tree are an indication that the tree will soon fall over.
A weak branch union sounds ominous and it can be. This is when the top of a tree, central leader was removed when the tree was small and two leaders are allowed to grow.
If the leaders grow big and move in opposite directions in the wind, a crack can form between the two trunks, down the central trunk. It is best to remove the tree at the first sign of a crack.
Trees decay from the inside out. This is not a problem until there is less than one inch (2.45 cm) of healthy wood to six inches (15 cm) of rotten wood. The exact health of the tree can be determined by taking a core sample at various heights. Another indication of decay is deep cracks in the main trunk.
Cankers are areas of the tree that have died from diseases.
They are easy to see as they will appear shrunken, or without bark. Many trees will live for years with small cankers. They become a problem when they reach over half way around the tree.
A good root structure is what keeps a tree upright. Disturb the roots of the tree or surrounding trees and the tree’s health is in danger.
As the root structure is underground, one has to look at the upper tree for clues to the roots health. Dead limbs and small leaves are both indications that the roots are having trouble supplying enough nutrients to feed the tree.
Another very serious indication is a small mound of dirt developing on one side of the tree. The mound is from broken roots. This is what anchors the trees into the ground.
The last indicator, poor structure, is usually a human-caused problem. If trees are poorly pruned to the point that large stumps are evident, the tree is more likely to have internal problems and need to be removed.
Many trees will grow for years without any problems, others not. To avoid expensive problems keep an eye on your trees especially if they are close to buildings.
Linda Tomlinson is a horticulturist and educator living in Rocky Mountain House. You can contact her at firstname.lastname@example.org