In my last article I wrote about the harmful effects of topping on trees, mostly deciduous (those that lose their leaves every winter). This time I will address topping of coniferous or evergreen trees.
While most people would think that removing the top of an evergreen is unsightly and harmful, there are several other actions that can be done to conifers that have the same effect. Shaping, crown raising, and of course removing the top of an evergreen will reduce the heath, vigor, growth, and defense of the tree. Unlike the deciduous tree, the conifer may not sprout multiple new shoots out of the top. Generally, a lateral branch will turn upward and assume the terminal role (become the new top).
Evergreen trees, especially spruce and pine, cannot be shaped or sheered like a shrub. Even the shrub-like pines will be severely damaged if trimmed back or shaped improperly. When the ends of an evergreen are sheered off, the buds that create the next year's growth are removed, and the branch cannot grow outward. Removing the buds does not hurt the tree, but the sheering between the buds will do the damage. Conifers cannot close the wounds made by sheering, and the chance for disease and decay is greatly increased. Furthermore, the thick look that is created after years of sheering will also increase the chance of needle fungi and insect infestations because of reduced air flow.
Finally, when it comes to the lower braches of spruce trees, they are only to be removed when completely dead. When the lower branches of spruce trees are removed, the tree's production of food is greatly reduced because those branches have the most leaves and thus, food production abilities. Spruce and Pine trees will slowly stop using the lower braches as they get older and can replace the food produced by them in the upper braches. When this happens, those branches can be removed with no harm done to the trees. Until that time, removal of lower branches will only harm the tree. In addition, when a lower branch is removed, the branch above it will only sag down further, prompting the removal of that branch and so on. This chain reaction will put the tree in a downward spiral.
Just as stated in my previous article, these acts are potentially expensive as they will need to be done each year to hold the desired look. When it comes to pruning your evergreens, the best action is no action at all.
By Sam Kezar, Certified Arborist
Sam Kezar, M.S. in Arboriculture, Member of the International Society of Arboriculture (ISA) and Minnesota Society of Arboriculture and ISA Certified Arborist, MW 4503AT.
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