Artificial Regeneration of Oak

Oak planting underneath a shelterwood or after clearcutting has been tried where natural oak regeneration was inadequate or greater species diversity was desired (Gottschalk 1983). However, both of these methods have had little success, mostly due to the poor height growth of planted oak seedlings. Although planted oaks usually have good early survival, height growth ultimately has been poor (McGee 1979a).

For example, McGee and Loftis (1986) found that although planted northern red and black oak on site-prepared clearcuts had good early survival, height growth was dismal despite periodic release. As Kelty (1988) points out, natural oak advance-growth seedlings need to reach 4.5 feet in height before they are able to respond to release, so it should be expected that small planted oaks might perform poorly in open conditions. Oak planting stock must be larger, older, or have a more favorable root/shoot ratio than is normally needed when planting more intolerant, pioneer species. Even when large, vigorous planting stock is used, fairly intensive treatments may be needed to ensure survival and stimulate height growth. Control of competing vegetation appears to be the most important requirement in achieving planting success with some species such as black walnut (Krajicek 1975; Hilt 1977). Repeated treatments may often be necessary, rather than the single release that is often adequate with conifer plantations, because of the slow initial response of seedlings. The situation is made more difficult by the fact that herbaceous competition affects hardwoods more than conifers (Bowersox and McCormick 1987). However, even effective weed control often does not result in rapid growth of planted oak seedlings (Hilt 1977; Wendel 1980).

The problem of stimulating the planted seedlings to outgrow competition has led to trials of underplanting seedlings beneath an existing overstory several years prior to harvesting. This may allow seedlings to develop sufficient size and vigor to respond rapidly upon release, while reducing the growth of intolerant competitors. For example, Johnson (1984) reported both establishment and relative height growth success after planting northern red oak seedlings underneath upland oak forests thinned to 60 percent stocking in Missouri. The overstory was removed after three growing seasons and stumps of undesirable vegetation were chemically treated both before planting and again during overstory removal. Another innovative but expensive remedy developed by British foresters is the placement of plastic shelters around individual hardwood seedlings; these alter the microenvironment such that seedling height growth is greatly stimulated (Kelty and Kittredge 1986).

Boyette (1989) concluded that techniques of planting oak seedlings and controlling competing vegetation are expensive and have limited application in the southern Appalachians (Roach 1971, Sander 1977, McGee 1979a, Farmer 1981, Sander et al. 1983, Crow and Isebrands 1986). Although these problems may be less important with intolerant species such as yellow-poplar, they will be encountered to some degree with all species that are best adapted to establishment as advance growth (Kelty 1988).

Because planting oaks is considered an experimental operation and is not widely practiced at this time, we have not synthesized the literature as we have that for natural regeneration. The reader is asked to review the papers listed below from the Oak Regeneration Symposium Proceedings (Loftis and McGee, 1993).

Suggested reading:

1. A Historical Perspective of Planting and Seeding Oaks (Phillip E. Pope)
2. Artificial Regeneration of Bottomland Oaks (Harvey E. Kennedy, Jr.)
3. Artificial Regeneration of Oaks in the Uplands (Todd W. Bowersox)
4. Oak Plantation Establishment (James H. Miller)
5. The Use of Tree Shelters and Underplanting for Oak Regeneration (James L. McConnell)

See: Collection and care of acorns