Five years of change in an old-growth pine-hardwood remnant in Ashley County, Arkansas
The Levi Wilcoxon Demonstration Forest near Hamburg, Arkansas is an industrially-owned remnant of old-growth pine and hardwoods. Some of the loblolly (Pinus taeda L.) and shortleaf (Pinus echinata Mill.) pine in this stand are over 200 years old, and numerous individuals exceed 90 cm in diameter and 30 m in height. A 2000 survey of a portion of this tract found that 27 tree species contributed an average of 387.5 live stems/ha and 31.8 m2/ha of basal area. An inventory of the same plots in 2006 yielded noticeable declines in density (now down to 342.5 stems/ha)and basal area (now 28.2 m2/ha). Much of this loss came in the aftermath of a windstorm in May 2003, which felled a number of overstory pines. Loblolly pine decreased from 49.6 stems/ha and 13.2 m2/ha in 2000 to 42.1 trees/ha and 11.2 m2/ha in 2006, while shortleaf pine declined from 21.7 treeslha and 5.0 m2/ha to 14.6 trees/ha and 3.5 m2/ha. Further pine mortality came from smaller-scale windthrow, lightning, and bark beetle infestations. Some hardwoods were also toppled by storms or crushed by falling trees, but most appear to have succumbed to drought, competition, and salvage logging. However, hardwood basal area remained virtually unchanged over this period, signifying adequate diameter growth and midstory recruitment. In particular, shade-tolerant hardwood species showed notable gains. Even though most overstory pines currently appear healthy, natural catastrophes and the lack of new canopy recruits may eradicate virtually all pines from this stand within 30 to 50 years.