Training poor quality nursery trees
Edward F. Gilman Professor, Environmental Horticulture Department University of Florida, Gainesville [email protected]
Trees are a lot like children; they require about 25 years of training to create good, solid structure that will last a lifetime.
First things first: Establish a pruning cycle and objectives. Pruning cycle depends on – quality of nursery stock (see Figure 1), growth rate, species, For example, for live oak: Two, four and eight years after planting.
Objectives for first 15 years:
- Establish a dominant leader by subordinating all but one codominant stem
- Space branches apart by removing or shortening nearby branches
- Anticipate future form and function – train and prune early to avoid cutting large branches which often initiates decay in the trunk.
Strategies At planting:
- remember, all branches are temporary on trees less than 4″ caliper
- do not remove more than about 25% of foliage
- remove or shorten leaders and branches competing with main leader (see Figure 2)
- if there is no single leader, create one by cutting back all leaders except one
Two years:
- remember, all branches are temporary on trees less than 4″ caliper
- do not remove more than 35% of foliage
- remove or shorten all competing leaders (see figure 2)
- shorten or remove large, low branches to improve clearance
Four years:
- most branches are still temporary
- do not remove more than 35% foliage
- remove or shorten all competing leaders
- shorten or remove large, low branches to improve clearance
- shorten or remove branches within 12″ of largest diameter branches in top half of tree
- there should be only one large branch per node (no clustered branches)
Eight years:
- remove or shorten competing leaders
- identify the lowest permanent branch and shorten any aggressive branches lower than this one (branch)
- remove or shorten branches within 12-18″ of largest diameter branches
Fifteen years:
- remove or shorten competing leaders
- identify several permanent branches
- remove or shorten branches within 18-36″ of permanent branches
- remove large branches lower (on the trunk) than the first permanent branch