Regeneration by Oak Seedlings and Stump Sprouts in Pennsylvania
Oak regeneration results from larger oak seedlings and stump sprouts. Guidelines to measure possible future regeneration are important for good forest management planning. Although guidelines have been developed for many oak forest types, no studies have been done in Pennsylvania or in areas with significant deer browsing pressure. Previous work has shown that oak dominance probabilities vary by site index, slope position, aspect, and geographic region, pointing out the need to produce data for Pennsylvania conditions.
Northern Research Station scientists studied oak regeneration in five upland species---white oak (Quercus alba), chestnut oak (Q. montana), scarlet oak (Q. coccinea), black oak (Q. velutina), and northern red oak (Q. rubra). They measured seedlings before harvest of the surrounding stand and at years 1, 3, 5, 7, and 10 after harvest. Study plots were located on four ecological sections within Pennsylvania: Northern Glaciated Allegheny Plateau, Northern Unglaciated Allegheny Plateau, Northern Ridge and Valley, and the Blue Ridge Mountains.
These NRS scientists worked to determine the survival and dominance probabilities of oak advanced regeneration and stump sprouts compared to associated hardwood competitors for 5 and 10 years after final removal cuts. They also determined if these probabilities varied significantly by site factors such as slope position and aspect and by ecological classification systems (that is, by ecoregion at the province and section level).
The majority (~60%) of stumps were dead by the fifth year, and more by the seventh. Survival varied by species and size class, with larger stumps and black and scarlet oaks having lower survival. Stump sprout height by species showed that scarlet oak, black oak, and chestnut oak are the fastest growing overall. Smaller stumps had a higher probability of producing dominant or codominant stems. The scientists found that 72% of the advance regeneration (large seedlings) was still alive after 7 years. The larger the preharvest size of a seedling, the larger the 5- and 7-year-old stem and the higher its dominance probability. The Blue Ridge Mountains ecosection had higher dominance probabilities in general and especially so for new seedlings. Since the stands that were studied have not yet reached crown closure, these results are preliminary and may change dramatically as competition intensifies with crown closure. The study stands will reach 10 years of age over the next several years.
- Gary W. Miller, USDA Forest Service- Northern Research Station Research Forester
- Patrick H. Brose, USDA Forest Service- Northern Research Station Research Forester
- Joanne Rebbeck, USDA Forest Service- Northern Research Station Physiologist
- Pennsylvania Department of Conservation and Natural Resources, Bureau of Forestry
Last Modified: 02/01/2016