Arthropod density and biomass in longleaf pines: effects of pine age and hardwood midstory
During a 2-year study we examined arthropod communities (density and biomass) on longleaf pines (Pinus palustris) in eastern Texas during spring, summer, and winter on trees in 3 age classes: 40-50, 60-70, and 130-1 50 years, as a potential food source for the red-cockaded woodpecker (Picoides borealis). We also examined arthropod density and biomass on the lower boles of 40-50 year-old longleaf pines in stands with and without a well-developed hardwood midstory. Pine age did not significantly affect total arthropod density on the lower boles of pines between the ages of 40 and 150 years during any of the 3 seasons examined. Total arthropod biomass, however, was significantly higher in 60-70-year-old pines than in 40-50 and 130-150-year-old pines during winter. During the breeding season, a period when adult red-cockaded woodpeckers are provisioning nestlings with food, total arthropod biomass increased steadily with pine age and was significantly higher in 130-150 year-old pines than in 40-50 year-old pines. During the post-breeding season, total arthropod biomass was unaffected by pine age. The presence or absence of hardwood midstory within 40-50 year-old pine stands had no significant effect on either total arthropod density or total arthropod biomass during any of the three seasons examined.