In 1997, I attended a class from a third-generation arborist, Tim Johnson. The topic of the lecture was “Pruning for the Life of the Tree.” I learned that proper pruning is an essential tree care practice we can undertake as tree stewards. You should prune a tree only when necessary. The tree will let you know if pruning is needed.
Some of the reasons for pruning are: to maintain good health, for safety reasons, to create good structure, to help increase fruit production, to keep a good size and for aesthetics.
One thing to keep in mind is the “right tree in the right place” when you are planting a tree. Keep in mind the mature size of the tree when you purchase it. The right placement will reduce some of the reasons for pruning.
There are many philosophies for the best time to prune. Pruning wounds the trees and reduces their leaves, which produce the trees’ sustenance.
The ideal times for pruning are when the trees are dormant, before budbreak and light pruning in the summer, which helps maintain tree structure. Dormant season starts around late November through March. Remember: Never prune a frozen tree.
Another thought on pruning is from Edward Gilman, an arborist who recommends pruning when a tree is in an active growth period, when the tree has the energy to respond to wound closure. In our area with vigorous growth, harmful pests, diseases and insects may be present.
There are many types of pruning:
• Crown thinning – removal of branches that are so tight, light and air are restricted. One saying is, “If you cannot throw your hat through the tree,” it needs pruning.
• Crown cleaning – removal of branches that are dead, diseased and declining, rubbing or broken.
• Crown reduction – is the selective removal of live branches to decrease the height and spread of a tree’s crown. Crown reduction should be performed by a qualified arborist who understands drop-crotch pruning cuts (itreeservice.com/pdfs/topping_and_crown_reduction.pdf).
• Crown raising – removal of the lower branches of a tree.
• Structural pruning – pruning trees when they are young, usually after they have been planted in the ground for three growing seasons.
Before pruning a tree, you should walk around the entire tree. Look for dead, diseased and declining branches, as well as branches that are rubbing or broken.
There are some key factors to proper pruning to keep in mind:
• Begin at the top of the tree and work your way down.
• Never remove more than one-fourth of the tree’s crown in a growing season. A pile of the discarded branches helps me calibrate the one-fourth.
• For deciduous trees, do not prune up from the bottom more than one-third of the tree’s total height.
• Prune small branches; they should be one-third the diameter of the branch you are pruning. Example, if the branch is 6 inches in diameter, remove limbs 2 inches or smaller.
• Use sharp and clean tools. Clean tools before each tree you prune with alcohol or Lysol mixture (10 percent).
Jones is a certified arborist in Taos and a member of the Taos Tree Board.