The tree marked with red paint is the crop tree; the author’s hand rests on the tree to be girdled.
By David Mercker Forestry, Wildlife, and Fisheries; University of Tennessee Agricultural Extension Service
fter the best sites and trees touch each other, growth rates are deadened. In other words, first find the are found and your equip-reduced. Thus, by deadening unwanted crop tree, then ask, “Deadening which ment is ready, you can begin trees whose crowns are touching the trees will improve my crop tree’s grow-releasing crop trees from crown of your crop tree, more space is ing condition?”
unwanted competition. You’ll need to created for expansion. When selecting crop trees look for the
locate those crop trees with good future following qualities:
growth potential. Availability of sunlight Releasing Crop Trees •Healthy trees -- those with potential
is the leading limiting factor of tree Condition your eye to locate trees for further development
growth. When crowns of adjacent trees needing release, not trees needing to be
8 / Alabama’s TREASURED Forests Summer 2003
The target is to release no more than 36 crop trees per acre. This equates to crop trees with an average spacing of 35 feet between each other. Spacing can be
deaden only those trees whose crowns are affecting your crop trees. Those in-between or below and not affecting the crop trees should remain. The leftover trees help to protect crop trees from wind damage and epicormic branching (unwanted branching on the lower bowl often caused by sudden increases in sunlight.)
Determine the trees to deaden. Using a chainsaw, turn the saw sideways and cut a complete girdle (ring) around the tree at a comfortable height (usually around three feet). Use proper safety procedures, as outlined in your saw safety manual. Then, cut another girdle at least six inches above or below the first one. Each girdle should be cut completely through the bark and into the live wood at least 3/4 inch. Make sure that each girdle meets at both ends so the vascular flow of water is completely severed.
Trees may take up to a year to die, but once dead, limbs fall off creating “snags.” Standing dead trees provide food (decomposing insects), as well as sites for nesting, roosting, denning, and perching for many species of birds and mammals. Standing dead trees further benefit wildlife by allowing sunlight to reach the forest floor, increasing forage for deer and nesting cover for wild turkeys and many species of songbirds. Increased sunlight in the stand also allows the crowns of crop trees to expand, which increases mast production
(e.g. acorns, beechnuts, and cherries),further benefiting wildlife.
Younger stands of pine trees are commonly thinned by logging, thereby generating an income rather than an expense. Why can’t the same early thinning be applied to hardwoods as well? In some circumstances it can be feasible, particularly where markets allow and conscientious loggers are available; but in many cases, it’s not feasible. Several characteristics unique to pine stands lend well to early thinning: increased or decreased according to the stand conditions. For example, some 35foot cells may not contain an acceptable crop tree, and that cell should be left. As a general guide, at least one-half of the 35-foot cells per acre should contain crop trees for the project to be justifiable.
You should deaden all trees whose crowns touch the crown of the crop tree on three to four sides. Special note:
Simulated aerial view of released crop trees. (Continued on page 10)
Summer 2003 Alabama’s TREASURED Forests / 9
(Continued from page 9)
Private landowners are beginning to view their hardwood forests as a vital part of their farm assets. Demand for fine-quality hardwood products such as cabinets, flooring, furniture, and veneer has increased and is expected to continue increasing for the foreseeable future. As a result, prices have escalated, causing astute landowners to consider an active rather than an incidental approach to managing their hardwood crops.
The slow growth rates of hardwood trees have long been viewed as an obstacle to forest management. Through minimal investment, CTR is a way to energize your forest. Growth rate is enhanced, forest composition is improved, harvest rotation is shortened, and revived enthusiasm for your forest investment results.
10 / Alabama’s TREASURED Forests Summer 2003