Marshall Tree Farm

Training poor quality nursery trees

Edward F. Gilman Professor, Environmental Horticulture Department University of Florida, Gainesville efg@gnv.ifas.ufl.edu

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:

Fig. 2. These branches are removed because the compete with the leader

Fig. 2. These branches are removed because the compete with the leader

  • 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