The Longleaf Pine Islands of the Ocala National Forest, Florida: A Soil Study
1984
Kalisz, Paul J. | Stone, Earl L.
Longleaf pine—wiregrass—turkey oak (Pinus palustris—Aristida stricta—Quercus laevis) occurs as isolated islands, 60—4000 ha in area, in a matrix of sand pine—scrub (Pinus clausa—Quercus spp.) on deep sands of the Ocala National Forest, Florida. Striking contrasts in physiognomy and species composition, and sharp, stable boundaries suggested that soil differences determined vegetation boundaries. Examination of soils to a 500 cm depth at 130 locations revealed no consistent differences in profile morphology, particle size distribution, or extractable nutrients. Thus the hypothesis that soil differences were responsible for the distribution of the two communities was not sustained. Organic matter and nitrogen contents of surface (0—60 cm) soils likewise did not differ between plant communities. Differences in surface horizon color were ascribed to differences in soil—forming processes: frequent additions of fine charcoal and active faunal mixing under longleaf pine vs eluviation under sand pine. Biogenic opal extracted from surface soils at 75 locations failed to provide evidence of long—term community stability. Isolines of total opal mass were concentrically patterned around longleaf islands, but opal mass and morphology did not consistently differ across vegetation boundaries.
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