-Since the 1950s the existence of natural hybrids between shortleaf pine and loblolly pine has been recognized and reported in the literature. In a range-wide study of isoenzyme diversity in shortleaf pine. we found 16 percent of the trees from western populations were hybrids. based on the isocitrate dehydrogenase (IDH) locus. In stands thought to be pure shortleaf pine in west central Arkansa...

A synthetic version of the CRY1Ac gene of Bacillus thuringiensis has been used for the transformation of loblolly pine (Pinus taeda L.) using particle bombardment. Mature zygotic embryos were used to be bombarded and to generate organogenic callus and transgenic regenerated plants. Expression vector pB48.215 DNA contained a synthetic Bacillus thuringiensis (B.t.) CRY1Ac coding sequence ̄anked b...

Leaf area index (LAI), needlefall (NF), and forest floor (FF) dynamics are tightly linked with stand productivity, nutrient cycling, and carbon, water, and energy exchange. We analyzed a long-term data set to quantify the impacts of stand development, site quality, and silviculture on LAI and litterfall (LF) in loblolly and slash pine plantations. LAI was significantly correlated with stand den...

The relationship between soil water availability, root extension, and shoot growth of lohlolly pine seedlings (Pinus taedu L.) was evaluated in a rhizotron sand mixture in the absence and presence of crabgrass (Digitaria spp.) competition. Heights and diameters of seedlings grown with crabgrass were reduced 33 and SO%, respectively, compared with seedlings grown in pine monoculture. Furthermore...

Southern pine plantations are increasingly established using herbicides to control herbaceous and/or woody competing vegetation to enhance growth, but little is known about the effect on wood quality. A study was established at 13 southern locations in 1984 to examine the effects of complete control of woody, herbaceous, and woody plus herbaceous competition for the first 3 to 5 years on the gr...

Following fertilization of forest plantations, high accumulations of nutrients in the forest floor creates the need to assess rates of forest floor decomposition and nutrient release. The study site was a 25-year old experimental loblolly pine plantation in the North Carolina Sandhills Region. Soluble and insoluble N, P, carbohydrate and phenol-tannin fractions were determined in foliage and li...

Loblolly and slash pine seed were inoculated at sowing with 1 of 12 different strains of plant growth-promoting rhizobacteria (PGPR) in the greenhouse. Time to germination and seedling densities were determined at 21 days, and seedling biomass was measured at 12 wk after sowing. All bacterial strains significantly increased the speed of seedling emergence over nontreated pine seed. By 12 wk, ho...

Loblolly pine (Pinus taeda L.) and shortleaf pine (Pinus echinata Mill.) have widely overlapping geographic ranges. Hybridization between the two species has interested tree breeders for a long time. Morphologically, the two pine species are different. The needles of loblolly pine are 6 to 9 inches long, usually with three yellow-green needles per fascicle; but shortleaf pine needles are 3 to 5...

Over the past few decades, reports of forest health problems have concerned scientists and forest managers in loblolly pine forests of the southeastern United States. Several interacting factors likely contribute to observed reductions in loblolly pine health, including low resource availability on many upland sites that were once dominated by longleaf pine. Currently, land managers are interes...