Root Density, Abundance, and Distribution in the Mixed Mesophytic Forest of Eastern Kentucky1
- P. J. Kalisz,
- R. W. Zimmerman and
- R. N. Muller2
Root density, abundance, and distribution to bedrock or to the 150-cm depth were measured in 40 soil profiles spanning a species compositional gradient. Profile morphology was relatively uniform for the soils examined. Root density (LV; length per unit soil volume) was not related to bulk density or coarse fragment percentage within individual sampling depths, and decreased exponentially from ranges of 18200 to 35900 m m−3 in the 0- to 5-cm depth, to 400 to 700 m m−3 in the 100- to 150-cm depth. LV in the upper 100 cm of soil was highest under oak-dominated forests on the xeric sites, averaging ∼ 60% greater than transitional or beech stands. Root abundance (LA; length per unit ground surface area) was not related to profile depth, and increased along the gradient from mesic to xeric forests. Total profile LA averaged 5800, 6400, and 10000 m m−2, respectively, under beech (Fagus grandifolia), transitional (primarily, Carya spp., Quercus rubra, and Liriodendron tulipifera), and oak (Quercus spp.) forests. LA in both Oe and mineral soil horizons increased in the order beech < transitional < oak. On the average, 17% of the root length occurred in the Oe horizon, 26% in the A horizon, and 90% within the solum to a depth of ∼ 65 cm. Variations in LV and LA across the species compositional gradient are most simply interpreted as species adaptations to sites with differing moisture regimes.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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