Quercus michauxii regeneration in and around aging canopy gaps

Floodplain forests are subject to frequent windstorms, which create canopy gaps and microtopographic heterogeneity. Forest regeneration may be enhanced when light and microtopographic conditions are both favorable, but slower growing canopy species may still require multiple disturbance events to reach the canopy. In 2001, we revisited a cohort of Quercus michauxii Nutt. seedlings planted in 1995 on pit–mound microsites that were constructed in and around canopy gaps to determine patterns of seedling persistence and investigate the effects of canopy openness and microtopography on seedling survival and growth. After 7 years, canopy openness in gap centers had decreased to levels that did not differ from levels in forest canopy. Seedling height and maximum root depth were greatest in gap centers, where light was initially greater but seedling growth rates declined over time. Soil moisture was greater in pits, where establishment and survival were very low. Roots of some seedlings reached from mound surfaces to depths and moisture levels comparable to those of adjacent pits, which might facilitate survival in both floods and droughts. Quercus michauxii can persist on elevated sites in aging gaps, and positive feedback in sites favorable for recruitment can enhance seedling growth; ascent into the canopy will likely require additional canopy-opening events.

Reforestation of Drained Beaver Impoundments

Performance of 1-0 bareroot green ash (Fraxinus pennsylvanica Marsh.), sycamore (Platanus occidentalis L), and baldcypress (Taxodium distichum L., Rich.) planted on drained beaver (Castor canadensis) impoundments in southwest Tennessee was promising at the end of three growing season.First-year survival was significantly increased in plots where swamp cut grass (Leersia oryzoides) was controlled; however, effective grass control opened the site to aggressive invasion by broadleaf herbaceous vegetation. No treatment effect was noted for survival or growth of seedlings by the end of the third year. Containerized seedlings of swamp white oak (Quercus michauxii Nutt.) and willow oak (Quercus phellos L) failed due to poorly developed planting stock. Natural regeneration 3 years after drainage was poor, averaging 333 boxelder (Acer negundo L.), 42 black willow(Salix nigra Marsh), and 21 cherrybark oak (Quercus falcata var. pagodaefolia Ell.) stems/ac. Continued beaver control was necessary to prevent recolonization of plantation sites. South. J. Appl. For. 16(3):151-155.

Development of Seven Hardwood Species in Small Forest Openings 22-Year Results

Small forest openings planted with seven leading commercial tree species were completely dominated by yellow-poplar (Liriodendron tulipifera) that averaged 90 feet tall after 22 years. Of the other planted species, swamp chestnut oak (Quercus michauxii) was most shade tolerant while Shumard oaks (Q. shumardii), water oaks (Q. nigra), and sweetgum (Liquidambar styraciflua) showed little tolerance.

Bottomland Hardwood Stand Development Following Clearcutting

A mature bottomland hardwood forest near Laurel, Mississippi was commercially clearcut in 1958 and the development of the ensuing naturally regenerated stand was traced. With increasing age, water oak (Quercus nigra) and white oak (Quercus michauxii) assumed a dominant position at the expense of blackgum (Nyssa sylvatica var. biflora) and ironwood (Carpinus caroliniana). At age 22, 13.4, 33.6, 51.5, and 4.6 ft² of the basal area was comprised of spruce (Pinus glabra) and loblolly pine (Pinus taeda L.), sweetgum (Liquidambar styraciflua), water oak, and white oak; iron-wood and blackgum comprised 14.8 and 1.8 percent of the basal area in trees less than 4 inches in diameter.