WHY IS IT IMPORTANT?
Oaks provide acorn crops that are essential to many wildlife species and sustainably provide high-quality sawtimber
Oak populations have been declining throughout the Appalachian region for decades
Oaks are a “disturbance” dependent species that require natural events like fire, storm damage, or logging to allow their special habit to thrive
Appalachia needs restoration of historically oak-dominated forests
WHAT IS OAK REGENERATION AND WHY IS IT IMPORTANT?
Oaks, such as white oak and northern red oak, are a particularly valuable species, both economically and ecologically. However, oaks have been declining across the southern and central Appalachians for decades. Successful oak regeneration is important to continue the sustainable supply of this highly valued hardwood for furniture, flooring, and lumber. Furthermore, oaks provide an irreplaceable, durable, highly nutritious food source (acorns, called ‘hard mast’), which many animals depend on, both directly and indirectly. Oaks provide a crucial base to the forest food web, as well as high quality habitat, for animals from birds to bears.
By managing oak forests sustainably and planning for oak regeneration, you can maximize your current and future timber profits. Furthermore, you can enhance wildlife habitat by increasing oaks to restore historic hard mast levels for wildlife, which have declined significantly in recent decades.
HOW IS THE OAK REGENERATION INFLUENCED BY FOREST MANAGEMENT?
Due to past clearcutting or high-grading (the removal of only the biggest trees of the most valuable species, like oaks) on oak forests, especially on the most productive oak sites, yellow poplar or maples often currently are taking over areas where oaks naturally occurred. Following these logging practices, which are unsustainable in oak stands, other species often outcompete the slower-growing oaks, which are also less likely to resprout from harvested mature trees. Efforts are now needed to restore oaks from such past mismanagement. Employing appropriate harvest techniques can achieve the best light regime to encourage oak reseeding and regeneration, particularly on drier sites to which most oaks are well adapted.
Fire exclusion from our forests for the past 100 years until very recently has also contributed to the decline of fire-tolerant oaks. They are outcompeted by the fire-intolerant young maples, birches, and poplars, or are choked out by dense thickets of fire-intolerant rhododendron and/or mountain laurel.
WHAT CAN PRIVATE LANDOWNERS DO TO ADVANCE OAK REGENERATION?
A professional, trained forester can help plan for successful oak regeneration where there are acorn producing oaks in the stand. On sites where oaks have decreased but are still a component, successful oak regeneration can result from management practices that mimic natural disturbance regimes, like group selection harvesting. Harvesting all the (non-acorn-producing) trees in an area from ½ - 2 acres in size creates ideal edge habitat with filtered light conditions for oak establishment from nearby oak seed sources. After 10 to 20 years, if advanced oak regeneration (at least 5-10 feet tall) has occurred, these group selections can be expanded to release the advanced oak regeneration around the edges. High-grading your oak forest should never be an option as it does not allow in enough light for oaks to regenerate and removes the best genetics from the stand. At the other extreme, oaks can usually not compete in the full sun of larger clear cuts with sun-loving trees like yellow poplar.
On drier sites that have remained oak-dominated to the present, drought-tolerant oak regeneration is more easily achieved by the above group selection method or a shelterwood harvest. A shelterwood harvest leaves mature healthy oak trees spaced 30-60 ft apart to provide seed and shelter for the future generation of oaks. In about 10 years if good advanced regeneration of oak has occurred these retained overstory trees could be harvested or left for habitat. On the other end of the spectrum, on moister cove sites that are dominated by fast-growing, moisture-loving poplars, slower growing oaks are usually not able to compete. High deer populations can also be problematic in areas, as deer like to browse the young fresh oak regeneration. Oak restoration must be site appropriate, a well-qualified forester can help you assess where and how oak regeneration could be increased.
Intermediate treatments between harvests to reduce the density of competing midstory trees can be helpful to oaks as well. These forest stand improvement thinnings can be conducted on relatively young mixed stands (4-8 inches in diameter) to release the oaks that are present from competition. Note again, however, that in moister areas where there is a significant presence of yellow poplar, young oaks may not be able to compete, even with help. These treatments also do come at a cost to the landowner and may only be effective if the oaks are at least as tall as the competition being controlled.
Controlled burning is another practice that can help with oak regeneration and recruitment into larger size classes. Oaks are fire tolerant, whereas many competing species (like maples and yellow poplar) are not tolerant of fire, particularly when they are seedlings or saplings. A successful burn will result in competition control that promotes oak regeneration. Conducting a controlled burn does have its challenges and requires very careful planning from professionals. If interested in pursuing a controlled burn, your local state Forest Service office may be able to provide this service.