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Abstract
The frequent scarcity of northern red oak (NRO) advance reproduction raises questions about its regeneration potential under prevailing stand conditions in eastern North America. In contrast, NRO plantations in France typically contain abundant advance reproduction. The purpose of this study was to document stand conditions in Pennsylvania (PA) and southwestern France (FR) that may be contributing to the difference in apparent regeneration potential. In each case, five mature stands or plantations were selected for study. The density of NRO advance reproduction was 2,500/ha In PA and 271,300/ha in FR. NRO stems were taller and older on average in FR than in PA; 15% of the FR cohort but only 2% of the PA cohort had survived beyond the fifth growing season. Basal area for all species averaged about 27 m²/ha in both regions, but NRO composed only 49% of the basal area in PA as opposed to 98% in FR. Canopy cover in June was significantly greater in PA stands by an average of 5.3%. Herbaceous ground cover averaged much higher in PA than in FR; it appeared that the abundance of advance reproduction in FR effectively excluded competition by herbaceous vegetation. Unfragmented leaf litter in May (dry weight / m²) was over twice as great in FR than in PA. Results demonstrate that NRO can accumulate abundant advance reproduction under relatively undisturbed canopy, at least in FR. Among the factors measured in this study, lower accumulations of leaf litter in PA as compared to FR may suggest poorer conditions for overwinter survival and germination of acorns in PA. Lower herbivore pressure and marginally lower canopy shade levels in FR compared with PA probably contribute to the superior success of advance reproduction in FR.
Citation
Steiner, Kim C.; Abrams, Marc D.; Bowersox, Todd W. 1993. Advance reproduction and other stand characteristics in Pennsylvania and French stands of northern red oak. In: Gillespie, Andrew R.; Parker, George R.; Pope, Phillip E.; Rink, George: eds. Proceedings of the 9th Central Hardwood Forest Conference; Gen. Tech. Rep. NC-161. St. Paul, MN: U.S. Department of Agriculture, Forest Service, North Central Forest Experiment Station: 473-483
