Epicormic Growth

The emergence of new shoots from dormant buds resting beneath the bark of a tree's trunk or main branches, typically triggered by sudden light or stress.

Epicormic growth refers to the sudden emergence of new, vigorous shoots from dormant or adventitious buds that sit nestled deep beneath the protective bark of a tree's main trunk or older structural branches.

In a healthy, balanced forest tree, these deeply buried buds are kept suppressed by chemical hormones produced by the active, dominant buds at the very top of the canopy. However, if the tree experiences a sudden environmental shock, stress, or alteration in its immediate surroundings, this chemical suppression breaks down.

Typical triggers for epicormic growth include a sudden increase in direct sunlight hitting the trunk following intensive forest thinning, physical canopy damage from a severe storm, or physiological stress caused by drought, root damage, or disease.

While epicormic shoots help a stressed tree rapidly expand its leaf area to capture more solar energy and survive, they present a major challenge in commercial hardwood timber forestry; these shoots create new branches directly along the clear length of the trunk, introducing knots into the wood that significantly lower the structural and financial value of the final log. Timber destined for decorative uses however can be highly-prized, producing figure known as 'cats-paws'.