Oak competitive status in 27-year-old group openings in a West Gulf Coastal Plain pine-hardwood forestThis article is part of a larger document. View the larger document here.
Due to their high ecological and economic value, oaks (Quercus spp.) are a desirable species group for mixedwood management. However, little information exists on oak competitiveness at the local, neighborhood scale in harvest gaps beyond the first few growing seasons. The objective of this research is to determine if oak competitive status is related to neighborhood composition and gap size. A total of 156 oak stems at least 3.5 inches in diameter at breast height and their respective neighborhoods were sampled in nine experimental harvest gaps (ranging in size from 0.25 to 1.0 acre) on the Kisatchie National Forest. Using neighborhood species importance values, a cluster analysis identified five neighborhood types: pine (Pinus spp.), pine-sweetgum (Liquidambar styraciflua), pine-oak, mixed hardwood-pine, and oak. No significant effects of neighborhood type or gap size were detected for subject tree heights or competition index; however, gap size was a significant factor in explaining red oak (section Lobatae) live crown ratio, and neighborhood type was a significant factor in predicting live crown ratio of all oaks. Red oaks in smaller gaps had significantly higher live crown ratios when compared to those in medium or large gaps. Oaks in pine neighborhoods had significantly lower live crown ratios when compared to neighborhoods with a greater hardwood component. These results suggest that managers should consider implementing timber stand improvement earlier in gap development to release oaks from pine and other shade-intolerant competition if earlier canopy recruitment of oak is desired. Alternative research approaches may be required to fully evaluate oak competitive status in gap cohorts initiated by group selection, such as stem analysis of oak subjects and neighbors and including oaks of all size classes.