Recurrent problems with regeneration of oaks (Quercus spp.) have been documented across a wide range of ecosystems. In oak-dominated forests of the central and Appalachian hardwood regions of the United States, a lack of competitive oak regeneration has been tied, in part, to fire suppression in these landscapes, and managers throughout the region are using prescribed fire to address this concern. To examine fire effects on oak regeneration, researchers have generally relied on inventories or population studies of existing seedlings. These studies are valuable but do not permit examination of the role of fire in enhancing the establishment and growth of new oak seedlings stemming from oak mast events. In this study, white (Quercus alba) and chestnut oak (Quercus prinus) acorn mast crops serendipitously occurred in year three (fall 2005) of a landscape-scale prescribed fire experiment. We examined establishment, survival, height and diameter of new seedlings on sites on the Cumberland Plateau in eastern Kentucky. Treatments were fire exclusion, a single prescribed fire (1x-burn; 2003), and repeated prescribed fire (3x-burn; 2003, 2004, and after acorn drop in 2006), all conducted in late spring. Initial densities of newly established chestnut and white oak seedlings were statistically similar across treatments (P=0.42), despite fires on the 3x-burn site having occurred after acorns were on the ground. Oak seedling density was significantly predicted by oak basal area on all sites (R2=0.12-0.46), except for chestnut oak on fire-excluded sites (R2=0.04). Litter depth was less on 3x-burn sites compared to 1x-burn and fire-excluded sites, whereas canopy openness was greater on both burn treatments compared to fire-excluded sites. Seedling mortality was generally higher on fire-excluded sites compared to burn sites, especially for white oak. Oak seedling mortality in the first two growing seasons was significantly predicted by initial litter depth and open sky, with greater litter depth and lower percent open sky leading to higher mortality. In the third growing season none of the measured variables predicted chestnut oak seedling survival; for white oak, percent open sky remained a significant predictor of mortality. Initially, seedlings on the fire-excluded sites had similar height but smaller diameter; after three growing seasons there were few differences in seedling height or diameter among treatments. Our findings suggest a potential role for prescribed fire in establishing forest floor and light conditions that may enhance the success of new oak germinants, although different responses among species may suggest the need to target management for individual oak species.
|Number of pages||9|
|Journal||Forest Ecology and Management|
|State||Published - Jul 2010|
Bibliographical noteFunding Information:
This research was supported by the USDA-USDI Joint Fire Science Program ( 01-3-3-14 , 04-2-1-06 ) through a cooperative research agreement with the USDA Forest Service Southern Research Station. We are grateful to the many people, too numerous to mention individually, who provided field support for this research. Special thanks, however, are warranted to Heather Alexander, Autumn Foushee, Jessi Lyons, and Gretchen Sovkoplas. Beth Blankenship provided essential technical editing and graphical support. We are also indebted to our USDA Forest Service collaborators from the Cumberland District of the Daniel Boone National Forest, including Jeff Lewis, EJ Bunzendahl, and David Manner. This study (#09-09-109) is connected with a project of the Kentucky Agricultural Experiment Station. This manuscript was greatly improved through the careful reviews and constructive comments provided by Jean-Paul Laclau and two anonymous reviewers.
- Chestnut oak
- Oak regeneration
- Prescribed fire
- White oak
ASJC Scopus subject areas
- Nature and Landscape Conservation
- Management, Monitoring, Policy and Law