Horticulture Principles and Practices

FIGURE 19–18 A low-hanging
branch may be propped up by
using a forked branch.
Forked branch
as prop
19.12 RENOVATING ESTABLISHED TREES
The purpose of renovation is to rejuvenate a tree that has been neglected for a long
time in order to restore tree form. Sometimes a tree may have to be felled. Pruning for
renovation may involve either minor or major cuts. Trees are usually renovated when
they are dormant. To avoid disease infection, wounds should be properly treated for
quick healing.
A tree may grow unevenly in terms of form or shape because it encounters an
obstruction that suppresses normal growth and development on one side of the tree.
When the obstruction is removed, the tree may be renovated to stimulate growth on the
suppressed part. As previously indicated, vigorous growth is restored to the suppressed
side by pruning that area.
584 Chapter 19 Pruning
19.13 S PECIAL TRAINING AND PRUNING TECHNIQUES
Sometimes trees may be cut back drastically to allow for new growth. The severe pruning
may be used to create unique and fascinating structures in the landscape. Examples
of such artistic creations are described in the following sections. It should be noted that
few species will tolerate this degree of pruning.
19.13.1 POLLARDING
Pollarding entails a severe pruning of the plant after it has attained its maximum desirable
height. Trees may be headed when they attain a height of 8 to 12 feet (2.4 to 3.6
meters). The tree top is cut back drastically during its dormant period (winter). Scaffold
branches are headed when they are about 2 to 5 feet (0.61 to 1.5 meters) long. When
spring starts, new buds sprout below each cut. These water sprouts are removed each year
as they recur. Repeated pruning leaves the tops of branches in clumps of growth resembling
stubs. Infection by decay organisms is minimal because the branches that are
pruned are small in diameter and hence incur only small wounds. This look is desirable
in spring, but in the fall and winter seasons, the plants look unattractive without the
foliage, though the stumps create some interest in the landscape. Ornamental trees that
may be pollarded successfully include elm, sycamore, poplar, and willow. The colorful
stems of dogwood (Cornus spp.) and willow (Salix spp.) add attraction to the stumps in
winter.
19.13.2 COPPICING
In coppicing, pruning is even more extreme than in pollarding. The tree is cut back to
leave a short stump (forming the stool) from which new growth emerges. Trees such as