The Art and Science of Good Tree Pruning
John Eisenhower, Phoenix Branch Manager, SavATree
A design precept states that form follows function. In simple terms it means that the way something looks often results from the way something works. If we understand the function, we can better understand the form. Beautiful trees in nature have a shape or form that compliments their natural growth pattern and their proper function in the landscape.
Good pruning is both an art and a science. It combines artistic expression and research-based data to make proper pruning decisions. When we prune trees with respect to their natural form and function, they always look their best…naturally!
When we get the science right, the art takes care of itself!
A first step in getting the science right is pruning only necessary plant parts. A tree’s leaves photosynthesize to produce the sugars and starches needed for new growth, defense, and reproduction. Over-pruning reduces a tree’s ability to generate those energy reserves needed for optimal tree health.
Getting the science right also means pruning to complement a tree’s natural growth pattern. Mesquite trees, for example, have a weeping growth habit with branches that grow downward, often to the ground. These low branches provide stability during windstorms as they block the monsoon winds from getting under the canopy. Removing too many lower branches creates a tree with a beach umbrella shape that can be easily blown over. So leaving low branches and instead lightly thinning the entire crown compliments a mesquite tree‘s natural growth pattern and the result is a stronger form. Getting the science right accommodates nature instead of fighting against it.
Finally, getting the science right means pruning to preserve good branch structure. This involves:
Removing or reducing unnecessary branches
Unnecessary branches include dead, dying, diseased, rubbing, and parallel branches, as well as branches with narrow angles of attachment. Competing branches that challenge the main trunk for dominance in the tree are also removed or reduced in size.
Avoiding Lion’s Tailing
Lion’s Tailing is the unacceptable practice of removing an excessive number of inner lateral branches from parent branches. This improper pruning creates lion tails of heavy foliage at the ends of branches. And this excessive end weight is responsible for a lot of wind damaged trees. Proper pruning aims for a more even distribution of foliage throughout the crown.
Encouraging interior foliage
Interior branches contribute significantly to overall tree health. They provide shade to the trunk and main branches. They also help their parent branches develop the taper necessary to support increasing end weight as the tree matures. And if crown reduction cuts are needed in the future, these secondary branches can become the new crown.
Arizona trees need special care in our extreme soil and climate conditions. By applying the art and science of good pruning, we’re confident they’ll remain safe, healthy, and beautiful!
