Impacts of silvicultural treatments on hardwood development and total stand productivity in loblolly pine (Pinus taeda) plantations in the Upper Coastal Plain and Piedmont

Abstract

I examined the impacts of six site preparation and post-planting silvicultural regimes on hardwood species composition, growth and total productivity index (pine plus hardwood biomass) at 19 locations through plantation age 21. Age 21 hardwood basal area was greatest in the Burn Only treatment plots (42.6 ft2/acre), followed by the Herbicide and Burn treatment (11.0 ft2/acre), Chop and Burn (9.3 ft2/acre), Chop, Herbicide, and Burn (8.8 ft2/acre), and Shear, Pile, and Disk (8.1 ft2/acre). Over all treatments, the most common genera present at age 21 was Liquidambar (50.0 % of hardwood basal area, BA), followed by Quercus (27.0 %), Carya (5.0 %), Prunus (4.6 %), and Nyssa (2.9 %). I classified sites into four hardwood abundance classes (Very Low, Low, Moderate, and High). Total productivity index (pine plus hardwood biomass) was greatest on sites classified as Low hardwood abundance for each treatment excluding Burn Only. Stands with greater pine to hardwood ratios tended to contain more total aboveground biomass than stands that contained more hardwoods.