Deadening Unmerchantable Trees
During a TSI operation, you can kill undesirable trees by chemical or mechanical means. If the trees are cut mechanically and you expect them to resprout, treat the stumps with an herbicide labeled for that use.
When undesirable trees have no commercial value, it often is faster and easier to kill them standing rather than to cut them down. Trees can be killed by girdling, frilling, herbicide injection, or basal spray (Figure 5-3). Dead standing trees are useful to many wildlife species and cause little damage to the remaining trees when they break up. For safety purposes, trees that could fall across roads or trails or on buildings should be felled rather than killed standing.
Fig 5-3. Methods for killing undesirable trees.
Girdling involves the complete removal of a 3- to 5-inch band of bark around the trunk with a hatchet or chain saw. Girdling also can be accomplished by encircling the main stem with two parallel chain saw cuts that are 1 inch deep and 3 to 5 inches apart. This is time-consuming, hard work; a tree may not die for several years; and live shoots may sprout below the girdle. Girdling often is used if sprouts are needed for wildlife browse and the resulting sprouts won?ft interfere with more desirable tree seedlings. Girdling is easier to do in spring when bark separates easily from the wood.
A frill girdle is a single line of downward axe or hatchet cuts that completely encircle the trunk and are then sprayed with an herbicide. Treatments during the growing season are more effective than treatments in winter or at the time of heaviest sap flow. The effectiveness also will vary with the concentration of the chemical used.
An herbicide injection can be used on trees over 5 inches in diameter. Some injectors are modified hatchets, while others resemble pipes with chisel points on one end. An injector cuts through the bark and injects a measured amount of herbicide into each cut. Space cuts 1 to 3 inches apart and apply this treatment any time from May through early fall.
To kill scattered shrubs or small trees, spray the lower 12 to 15 inches of the stem with an approved herbicide till it runs off. Apply chemicals during the growing season, and note that control may be poor on root-suckering species.
Do not apply chemicals near desirable plants or contaminate surface or ground water.