Storm Damaged Trees—How Much Damage Is Too Much?

The June 16 windstorm and tornado activity wreaked havoc on area trees.  Trees that are snapped in two are obvious candidates for removal, but what about those trees that lost a large limb and the rest of the tree is intact?  Should those trees be removed or can they be saved?

An excellent example is this ornamental pear.  When the branch broke, the weight of the falling limb peeled the bark downward, enlarging the wound and revealing the sensitive cambial layer, the conductive tissue of the tree.  The cambial layer dies when exposed to air, then interfering with water and nutrient transport up the tree. It’s also likely this wound will serve as entry for decay organisms.

If the area surrounding the wound comprises 2/3 or more of the trunk circumference and is in good shape, then physically the tree can hold up the canopy. That alone isn’t enough to determine the tree should be saved, however, and the extent of the damage necessitates the need for further evaluation. The size of the wound alone will take a number of years before the tree can grow enough callus tissue to cover the damaged area.

In this case, the dark wood in the wound indicates this ornamental pear had decay, made worse by included bark.  This decay weakened the branch, increasing its chances of breakage during heavy wind and snow loads.  Included bark is the physical defect that occurs when a branch grows too close to the trunk.  As the trunk and branch grow in girth, bark that is normally sloughed off instead gets caught between the two. The included bark is not only a structural defect but also allows decay organisms to enlarge the wounds, causing further structural instability.

When tree wounds are large, as in this tree, the long term outlook is not rosy.  Rather than having years lost to an unhealthy tree, why not get a jump start by planting a new tree now?

ornamental pear 1


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