Monday, November 19, 2012The primary objective of pruning young trees is to develop a framework of sturdy, well spaced branches on a strong trunk. Good branch structure, proper form, and tree strength all develop with training pruning.
Pruning done early in a tree’s life removes weak branches and corrects form when branches are relatively small. This reduces the size of pruning wounds, which results in faster closure and less opportunity for decay.
Properly pruned and trained trees will live significantly longer; are healthier; require less corrective pruning later. They will also be less susceptible to storm damage due to improved structure, and are therefore safer.
Pruning is especially critical in the first 15-20 years of a trees life. The pruning cycle should begin 2-3 years after planting and be done at regular intervals. The pruning process removes portions of the tree to correct or maintain tree structure and form. Every cut has the potential to change the growth of the tree. Good pruning technique removes structurally weak branches while maintaining the natural form of the tree and the branch collar.
The goals of early structural pruning are trunk development and branch positioning. We know the growth habit of a tree before beginning the pruning process. Over- thinning or over-pruning are avoided. The leaves of each branch must manufacture enough food to keep that branch alive, as well as contribute to growth of the trunk and roots. We strive to not remove more than 25% of the foliage; 10-20% maximum is usually the goal.
Efforts are concentrated on removing crossing, rubbing, broken, diseased and weak angled branches in the upper portion of the tree. We strive to eliminate double leaders and basal sprouts, selecting and developing one main leader on most species. “3-D” pruning is done to remove dead, damaged, and diseased portions.
The best form for most young trees is to maintain a single dominant leader growing upward. This leader is not pruned back nor are secondary branches allowed to outgrow the leader. Double leads, known as co-dominant stems, can lead to structural weakness, so it is best to remove these while the tree is young.
Temporary branches are not part of a mature tree’s crown, but do contribute to trunk development and protect the trunk from sun and mechanical injury. Temporary branches are in the lower third of the crown. They will eventually be removed when an inch or larger and should not obstruct or compete with selected permanent branches.
Permanent branch selection is determined by the tree’s function and location in the landscape. Proper selection and establishment of these branches is a critical part of pruning. Branches selected as permanent branches must be well spaced along the trunk. Branches are removed that have a much narrower angle of attachment than is typical of the species. All branches should be less than ½ the trunk diameter.
Remember that pruning is an ongoing process to be done regularly throughout a tree’s life. Proper training pruning will get that tree off to the best start. Pruning is both an art and a science. Let the Certified Arborists at Wachtel make your trees be the best they can be.