The rapid transformation of the Brazilian Amazon through expanded logging, ranching and fire has left in its wake an impoverished resource base for large numbers of forest-dependent peoples. How current changes in land use may affect the density and distribution of widely used fruit, medicinal, fiber and game species is not known. Also unknown is how the use, management and value of forest products may change in response to the changing structure and composition of forests. Although economic studies have demonstrated that the value of non-timber forest products can exceed that of timber, many Amazonian smallholders live in areas of low-density economic species, with long distances to market, and in regions undergoing logging, ranching and fire. The lack of locally relevant data and the rapid expansion of the timber industry in Amazonia has meant that many Amazonian communities sell trees for scant sums, without fully understanding the relative value of those forests' timber and nontimber resources. In this dissertation the use, ecology and value of non-timber forest resources in a rapidly changing frontier area along the Capim River region in eastern Amazonia are examined. The six-year ecological study focused on three fruiting species, which had received scant prior study: Caryocar villosum (Aubl.) Pers., Endopleura uchi Cuatrec. and Platonia insignis Mart. Findings indicate that they exist in low densities, have complicated phenological cycles, undergo extreme variations in annual yield, and are widely consumed by humans and wildlife. At present, these fruiting species, as well as twelve of the most highly valued medicinal oil and game attracting species, are consumed by the timber industry, thus posing detrimental consequences to the health and nutrition of caboclo communities in the study region. Results also demonstrate that in selectively logged forests, the subsistence value of non-timber forest resources can be substantial; that the most valuable non-timber forest products, fruit and game, are not destined for regional, national or international sale; that even in high biodiversity, low density terra firme forests, the net present value of NTFPs can exceed that of timber; and that, in spite of this comparatively higher value, non-timber species of substantial worth are currently being extracted for their timber. Findings underscore that there is a critical limit to the volume of timber that can be extracted from forests, after which present and future harvests of non-timber resources plummet. Results also suggest that women's participation in land-use decisions positively effects forest management. Taken together, these findings question the common assumption that sale of non-timber forest products is possible and/or desirable for all rural communities. Instead, results highlight the need for increased forest extension to assist communities to weigh the costs and benefits of logging; to negotiate for just benefits; and to promote forest management that includes NTFPs for subsistence use and occasional sales. Findings also suggest that, for the benefit of domestic economies, policy makers need to address the interface of non-timber forest resources and timber extraction