Winter Pruning is for Branch Structure
by Larry Ryan - February 2006
Winter provides a unique opportunity to study branch structure of trees. This study can lead to corrections of poor or weak branching in trees and shrubs. Things to look for include rubbing or cracked limbs, limbs growing into your home or utility wires, and co-dominant leaders.
DEFINITION: First, let's define the co-dominant leader. Normally most varieties of trees have one leader that grows vertically that branches radiate from. Occasionally a tree will have more than one leader growing side by side vertically. If these branches are attached with a narrow angle, it makes for a weak branch union. As the tree ages, the narrow branch angle will weaken the branch. One or both of these limbs are prone to plit off during high wind, snow or ice.
We see co-dominant leaders frequently in pin oaks and red maples, but we also see them at times in most other tree species. If you study the Bradford pear closely, its limbs are really a mass of co-dominant leaders. This is why the Bradford is so prone to break in storms.
The very best solution to this problem is to prune regularly when trees are young. Examine trees annually for poor branching. If you notice a co-dominant leader, remove it. The branches will still be small, the wound will quickly heal, and the shape of the tree will not be deformed.
In older trees where the leaders have been growing for years and the branches are larger, there are two options. One is the removal of the weakest leader over several years. This is what arborists call subordination pruning. A portion of the branch is cut back each year for two or three years until the entire branch is removed. This allows the tree a chance to adapt to the removal of a large portion of the crown. A second option for larger co-dominant leaders involves cabling the branches together for support. Consult a professional arborist for advice on which option to use in your tree.
At Ryan Lawn and Tree, our arborists look at thousands of trees every year. We observe those trees which are regularly maintained from planting on seldom need cabling or removed due to severe flows in branching. Regular corrective pruning is key to maximizing correct tree growth.
BEST TIME TO PRUNE? You will hear that there are best times to prune your trees. Having pruned for a number of years and watched trees after pruning, I today tell people to prune anytime. You may find walnut trees and birch bleed if pruned at certain times in the spring, but I have not found this hurts the tree. If can be more of an annoyance if the tree hangs over a deck or sidewalk. Often times you will find better rates when you contract pruning off-season. If you call a compnay in May to have major pruning done, expect to wait a few weeks to several months. Late spring is when quality companies get backed up with work.
Larry Ryan is owner and operator of Ryan Lawn & Tree. He can be reached at 913-381-1505.