Litterfall in the hardwood forest of a minor alluvial-floodplain

Within mature deciduous forests, annual development of foliar biomass is a major component of aboveground net primary production and nutrient demand. As litterfall, this same foliage becomes a dominant annual transfer of biomass and nutrients to the detritus pathway. We report litterfall transfers of a mature bottomland hardwood forest in a minor alluvial-floodplain within the middle Coastal Plain physiographic province of central Louisiana, USA. Climate is humid subtropical. Floodplain forests of minor alluvial-streams may account for nearly half the remaining acreage of bottomland forests in the Southeastern USA and differ markedly from those of major alluvial-rivers and deep-water swamps. For a 3-year period, litterfall magnitude, components, leaf species, and timing were monitored by monthly collection of materials from litterfall collectors. Variations in litterfall transfers across 10 study-plots and their relationships to forest parameters are evaluated. Mean transfers of total litterfall, leaf fall, reproductive structures, fine wood, and other litterfall were 816, 512, 130, 98, and 76 g m(-2) year(-1), respectively. Quercus pagoda Raf., Q. nigra L., and Liquidambar styraciflua L. accounted for an average of 49% of annual leaf fall, with 11 tree species and canopy vines accounting for 94% of total annual leaf fall. A total of 38 species and genera contributed to total leaf fall. Variation in total litterfall and leaf fall transfers across the alluvial bottom were related to size of overstory trees and their species composition. Higher and more consistent mass transfers of reproductive structures were observed than previously reported for upland hardwood stands. (c) 2006 Elsevier B.V. All rights reserved.