Gradient Analysis of Pitch Pine (Pinus rigida Mill.) Lowland Communities in the New Jersey Pinelands

Abstract

ZAMPELLA, R. A. AND G. MooRE (New Jersey Pinelands Commission, New Lisbon, NJ 08064) AND R. E. GOOD (Division of Pinelands Research, Institute of Marine and Coastal Sciences, Rutgers University, New Brunswick, NJ 08903). Gradient analysis of pitch pine (Pinus rigida Mill.) lowland communities in the New Jersey Pinelands. Bull. Torrey Bot. Club 119: 253261. 1992.-Gradient analysis was used to relate water-table level, soil moisture, soil texture, available nutrients, and disturbance to forest composition along pitch pine dominated lowland community gradients in the New Jersey Pinelands. Twenty-seven forest stands were classified as mesic pine-scrub oak forest, dry pitch pine lowland, wet pitch pine lowland, or pine-maple swamp. Stand position along the first axis of a detrended correspondence analysis (DCA) ordination contrasted the distribution of upland versus wetland species. The DCA axis was correlated with forest stand position along the first axis of a principal component analysis (PCA) ordination of environmental attributes. The PCA axis represented a complex upland to wetland environmental gradient characterized by decreasing depth to water-table and bulk density and increasing soil moisture and soil organic matter. The percentage of fine sand in the A horizon and pH also decreased along this gradient, and the percentage of medium sand in the A horizon, ammonium, and stand age increased. Soil moisture and bulk density best characterized the complex environmental gradient. However, because changes in soil moisture and soil organic matter are functionally related to water-table level, hydrologic regime may be the primary factor underlying observed vegetation patterns along pitch pine lowland gradients in the New Jersey Pinelands.