Establishing Oak Regeneration

Oak can be regenerated by several silvicultural methods and managed either as even-aged or uneven-aged stands. Oak seedlings and sprouts cannot grow into the overstory as long as they are heavily shaded (Johnson, 1993). Therefore, clearcutting, shelterwood, group selection, or other methods that substantially reduce overstory density are usually used to regenerate oak stands (Hannah 1987, Sander and Clark 1971). However, treatments to stimulate oak height growth often trigger an overwhelming response by competing vegetation or can expose the seedlings to frost or freezing problems. There is a fine line between just enough light only to stimulate oak seedling growth and too much light, thus stimulating shade-intolerant reproduction. In the following sections, concepts and techniques for establishing oak regeneration are reviewed.

• Oak regeneration potential: The key to replacing current oak stands with new oak stands is having well-established oak advance reproduction in place when the final harvest is made. Therefore, the first step in planning for oak regeneration is to evaluate the oak regeneration potential, or, the potential of the oak advance reproduction plus stump sprouts to replace the current stand. The oak regeneration potential can be poor (seedlings or saplings not present), marginal (seedlings present but not tall enough), or adequate (saplings present and at least 4.5 ft. tall). In reality, the situation where numerous oak understory stems are greater than 4.5 ft. rarely occurs (C. Smith, 1993).
• Management implications of acorn production: Seed production for oaks, particularly red and white oak, is very sporadic and unpredictable. To be successful in establishing oak seedlings, good-to-bumper acorn crops are necessary to assure there are enough to feed wildlife and still have acorns to germinate new seedlings. However, planning forest management practices around production of acorns has too much uncertainty in the Appalachians to be effective. Maintaining the good acorn producers in the stand in a dominant position is currently the only practical management means to enhance acorn production. (C. Smith, 1993)
• Naturalregeneration methods: Oak can be regenerated by several silvicultural methods and managed either as even-aged or uneven-aged stands. Among the various natural regeneration methods researched, the shelterwood method is probably the most promising method for regenerating oaks in the southern Appalachians. Group selection methods are also potentially suitable for regenerating northern red oak. Although clearcutting has been a widely recommended method for xeric sites, it has been less successful in regenerating oaks in the more mesic ecosystems of the Appalachians. Single tree selection is very restricted in its application in the southern Appalachians.
• Artificial regeneration methods have also been attempted to enhance oak regeneration, but these attempts have been met with little success in the southern Appalachans.
• Site preparation treatments: Site preparation treatments, such as herbicides and fire can be used to control competing vegetation in regenerating oak stands. However, continued political constraints and social concerns related to using herbicides may result in limited to perhaps no use of herbicides on public forest lands. Fire would also be a difficult tool to apply from a practical basis because many of the good sites would be difficult to burn under prevailing weather conditions. Mechanical site preparation techniques are less common for oak management.
• Knowledge gaps: Despite the wealth of research on establishing oak regeneration, serious gaps remain.