Development of cherrybark oak and sweet gum in mixed, even-aged bottomland stands in central Mississippi, U.S.A.

Abstract

Development of even-aged mixed cherrybark oak (Quercusfalcata var. pagodifolia Ell.) and sweet gum (Liquidambarstyraciflua L.) stands was examined over a range of stand densities and ages in minor river bottoms of central Mississippi, U.S.A. Two stand development patterns were documented based on average spacing between dominant and codominant trees during the pole stage of development: a "restricted" pattern and an "unrestricted" pattern. The restricted pattern occurred at average spacings of less than 5.5 m. Here cherrybark oak was initially shorter than sweet gum but was able to outgrow and stratify above sweet gum when the stand was 20 to 25 years of age. Dominant and codominant cherrybark oaks averaged 61 cm in diameter, 34 m in height, and had 15 m of merchantable height at 58 years. The unrestricted pattern was found where cherrybark oak was either a few years older than sweet gum or was essentially open grown, with dominant and codominant trees of either species being more than 5.5 m apart. The unrestricted pattern resulted in cherrybark oak attaining less than 8 m of clear merchantable length and diameters of 56 cm in 40 years. The spacing of interacting trees appears to be responsible for the differences between the two development patterns in the timing and rate of cherrybark oak crown expansion, diameter growth, and length of the merchantable bole.

Proceedings of the Seventh Biennial Southern Silvicultural Research Conference

“…Since cherrybark oak in particular is capable of competing with sweet gum in bottomland forests (Clatterbuck and Hodges 1988), and since sweet gum is a major competitor in this study area, oak seedlings produced from intermediate harvest operations should become part of the dominant canopy of the next stand.…”

“…Many stands have been clearcut with the expectation of adequate oak reproduction only to result in a greatly diminished quality oak component after crown closure. The relative maturity of many stands, past high grading and lack of oak advance reproduction at harvest time have resulted in stump sprouts and seedlings of vigorous early-successional species gaining early dominance in these bottomland stands (Johnson 1984;Aust et al 1985;Clatterbuck and Hodges 1988;Nix 1989;Nix and Barry 1992).…”

“…However, it is unclear at present if advance oak reproduction is as important in bottomland oak regeneration as it is in upland oak regeneration due to the competitiveness of bottomland oak seedlings on good oak sites (Clatterbuck and Hodges 1988;Guldin and Parks 1989;Nix 1989). Recently the opportunity arose to follow the development of numerous young oak seedlings in two clearcut bottomland hardwood stands in South Carolina.…”

“…Many mixed bottomland hardwood stands are dominated by oak species (Clatterbuck and Hodges 1988) and provide mast for wildlife. Cherrybark and shumard oaks are among the most valuable components of bottomland hardwood stands Janzen 1986, Johnson 1979) and are capable of producing quality saw logs in 60 years (Hook and Stubbs 1965).…”

“…are two of the large, high quality bottomland oaks (Miller and Lamb 1985) that are losing their place in the bottomland hardwood forest. The ecology and biology of bottomland oaks have been investigated to determine why the number of oaks are decreasing in new stands of the bottomland forests (Johnson 1979, Guldin and Parks 1989, Clatterbuck and Hodges 1988. From these studies it appears that bottomland oaks are decreasing in number due to the slow growth of newly established oak seedlings which cannot compete successfully with sprouts and fast growing pioneer species.…”