Tom A. Stokes

Growth and physiology of loblolly pine in response to long-term resource management: defining growth potential in the southern United States

Leaf physiology and stem growth were assessed in loblolly pine (Pinus taeda L.) in response to 10 to 11 years of treatment with weed control (W), weed control plus irrigation (WI), weed control plus irrigation and fertigation (WIF), or weed control plus irrigation, fertigation, and pest control (WIFP) to determine whether increased resource availability can push productivity of loblolly pine closer to its biological growth potential expressed in favorable, exotic environments. Maximum basal area and stem biomass were 41 m 2 ha -1 and 172 Mgha -1 , respectively, in response to fertigation. Stem- wood biomass production was positively and linearly related to basal area. Belowground woody biomass was highest in the WIF and WIFP treatments and averaged 50 Mgha -1 , but the W and WI treatments exploited a greater area of soil with low-density coarse roots. Fertigation increased foliar nitrogen concentration and foliage biomass, but treatment had no effect on leaf physiological parameters or growth efficiency. Comparison with growth rates reported for loblolly pine in Hawaii revealed that loblolly pine grown in its native range can produce the high yields observed in exotic environ- ments when stands are below maximum carrying capacity.

Maximum growth potential in loblolly pine: results from a 47-year-old spacing study in Hawaii

Growth, allocation to woody root biomass, wood properties, leaf physiology, and shoot morphology were examined in a 47-year-old loblolly pine (Pinus taeda L.) density trial located in Maui, Hawaii,...

Influence of poultry litter fertilization on 18‐year‐old loblolly pine stand

Abstract The influence of a surface application of 4.5 and 9 magnesium (Mg) ha‐1 (fresh weight) poultry litter and 112 kg ha‐1 diammonium phosphate (DAP) on soil chemical characteristics, foliar nutrient concentrations, and stem diameter growth in an 18‐year‐old loblolly pine (Pinus taeda L.) stand was examined. Nitrogen (N) and phosphorus (P) were applied at a rate of 119 and 53 kg ha‐1, respectively, in the 4.5 Mg ha‐1 poultry litter treatment and 24 and 27 kg ha‐1, respectively, in the DAP treatment. No treatment effects on soil N or NO3‐N concentrations 6 and 18 months after treatment were observed, but greater N concentration in current‐year‐needles was observed four months after treatment in response to 9 Mg ha‐1 poultry litter. Six and 18 months after treatment, 9 Mg ha‐1 poultry litter increased P concentration in the 0–15 cm layer of soil relative to the control. Poultry litter and DAP treatments increased foliar P concentration, but the largest increase in foliar P concentration was observed in ...

Structure and Diversity of Longleaf Pine (Pinus palustris Mill.) Forest Communities in the Mountain Longleaf National Wildlife Refuge, Northeastern Alabama

ABSTRACT: The Mountain Longleaf National Wildlife Refuge (MLNWR), located in northeastern Alabama, is unique in that it holds significant acreages of young and old-growth montane longleaf pine forest (Pinus palustris Mill.). We conducted a study to aid in the management and restoration of longleaf pine communities on the MLNWR. Our objectives were to: (1) establish permanent forest monitoring plots; (2) document herbaceous and woody vegetation; and (3) measure forest diversity, structure, and fuel loads in montane longleaf pine communities with varying fire and management histories. We established 48 plots, 0.04 ha in area, in winter 2008 and measured all plots in summer 2008. The MLNWR has recently incorporated prescribed burning in their management plans and each plot was categorized by the year it was burned (2008, 2006, 2004, no-burn) and whether hardwood control treatments were applied. We identified 18, 19, and 22 different woody plant species in the overstory, mid-story, and understory, respectively, across plots. Longleaf pine basal area ranged from 5 to 10 m2 ha-1 and represented as much as 80% of basal area across plots. Mid-story basal area and woody plant species diversity were lower in plots receiving fire or hardwood control. Longleaf pine regeneration was found in only 17 plots and was highest in burned plots or plots receiving hardwood control. Burning also increased grass and herbaceous ground cover. Fuel loads were high with an average humus layer accumulation of 35 Mg ha-1. Regular fire intervals are needed to reduce fuels and mid-story density and aid in the regeneration of longleaf pine.