Pruning Trees: The Problem of Forks
Abstract: The term "fork" in a tree describes an axis that gives rise to two or more equivalent axes, which together form sharp angles. Forks can appear on the trunk or on the branches at various times in the life of a tree. A fork on a trunk during formation is a potential defect likely to ruin the straightness of the tree, reduce the length of the trunk, and lead to enclosed bark. For these reasons, it is generally advisable to eliminate forks and straighten large branches by formation pruning. Not all tree forks are alike; some require intervention, but others are reabsorbed on their own. We propose classifying forks into four major categories: temporary forks, recurrent forks, main forks, and accidental forks. Each category is the subject of a morphological description, an analysis of the causes of forking, a prediction of the length of life of the forks, and a discussion on the advisability of formation pruning.
Keywords: Tree architecture; formation pruning; pruning; forks.