Mixed potential for sustainable forest use in the tidal floodplain of the Amazon River L.B. Fortini a , F.G. Rabelo b , D.J. Zarin a, * a School of Forest Resources and Conservation, Institute of Food and Agricultural Sciences, University of Florida, P.O. Box 110760, Gainesville, FL 32611-0760, USA b Instituto Matoense Municipal de Ensino Superior, Av. Tiradentes, 629, Centro, Macapa ´, Amapa ´ 68906, Brazil Received 13 May 2005; received in revised form 22 February 2006; accepted 24 April 2006 Abstract We evaluated the structural and compositional variability between floodplain forest sites in the Amazon estuary. Although tidal floodplain forests have been commonly perceived as a homogenous forest type, comparisons of basal area and stem density show that, from one locale to another, these forests can vary greatly in structure. Comparisons of common diversity indices along with detrended correspondence analysis and indicator species analysis also reveal marked compositional differences. Local structural and compositional differences result in contrasting potential for alternative forest uses such as timber, latex, fruit and seed-oil production. For example, areas with high dominance of palms, important features of the estuarine landscape, tend to have lower potential for timber management. While some previous research in the Amazon estuary has emphasized the forest management for timber, other studies have focused primarily on the importance of non-timber forest products for subsistence and market economies, and for conservation. Our results indicate that contrasting views of the management potential of Amazonian tidal floodplain forests reflect not only heterogeneity of forest use by riverine people, but also the heterogeneity of the forests themselves. # 2006 Elsevier B.V. All rights reserved. Keywords: Amazon estuary; Floodplain forests; Forest management; Forest heterogeneity 1. Introduction The tidal floodplain forests of the Amazon estuary have supported timber harvesting since at least as early as the 17th century, but in a much more selective form (in size and species) than modern extraction. Beginning in the late 1950s, large saw and plywood mills were established in the region during a period of intense exploitation that lasted until the 1980s. During that period, Cedrela odorata, Virola surinamensis, Carapa guianenesis, Hura crepitans, and Maquira coriaceae were the most sought-after species (Raffles, 1999). Since then, small- scale logging and milling operations have replaced the larger sawmills (Barros and Uhl, 1995; Pinedo-Vasquez et al., 2001). The persistence of logging activity in the region suggests an underlying potential for sustainable management of timber production that is bolstered by a high number of timber species, the relatively low impact of extraction due to water transport, relatively fertile soils, and well-developed local ecological knowledge (Anderson, 1990; Hiraoka, 1992; Zarin et al., 1998; Laurance, 2001). While some researchers suggest that smallholders are managing timber production sustainably in the region (Pinedo-Vasquez et al., 2001; Sears and Pinedo- Vasquez, 2004), others have argued that sustainable manage- ment is largely unrealized and that timber resources are being depleted (Macedo and Anderson, 1993; Barros and Uhl, 1995). Additionally, non-timber forest products, especially the ac ¸aı ´ palm (Euterpe oleracea), have become increasingly important in the subsistence and market economies of floodplain inhabitants (e.g. Brondizio, 2004). It is unclear whether non- timber forest products are complementary or incompatible with timber production and forest conservation (Alavalapati and Zarin, 2004). Most forest management in the Amazon estuary now occurs on plots of <100 ha (Sears and Pinedo-Vasquez, 2004) and region-wide generalizations are not particularly relevant to this scale unless conditions are homogeneous. Within the Amazon estuary, there are few cross-site comparisons (Almeida et al., 2004). Previous regional analyses of vegetation cover in the www.elsevier.com/locate/foreco Forest Ecology and Management 231 (2006) 78–85 * Corresponding author. Tel.: +1 352 846 1247; fax: +1 352 846 1332. E-mail address: zarin@ufl.edu (D.J. Zarin). 0378-1127/$ – see front matter # 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.foreco.2006.04.038