Compatibility of timber and non-timber forest product management in natural tropical forests: perspectives, challenges, and opportunities Guariguata, M.R.; García-Fernández, C.; Shiel, D.; Nasi, R.; Herrero-Jáuregui, C.; Cronkleton, P.; Ingram, V.J.

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Neurogenin 3 (Ngn3), a proneural gene controlled by the Notch receptor, is implicated in the control of dendrite morphology and synaptic plasticity of cultured hippocampal neurons. Here we report the localization and subcellular distribution of Ngn3 in the hippocampus in vivo and in neuronal cultures. In situ hybridization showed Ngn3 mRNA expression in the pyramidal layer and dentate gyrus of adult mouse hippocampus. Immunohistochemistry studies revealed that Ngn3 localization is mostly cytoplasmic in the hippocampal eminence at embryonic day (E)17 and postnatal day (P)0. At P10 it is cytoplasmic in CA1-CA3 pyramidal neurons and nuclear in granule cells of the dentate gyrus. In the adult hippocampus Ngn3 is localized in the nucleus and cytoplasm of both pyramidal neurons and granule cells. During development of cultured hippocampal neurons, Ngn3 mRNA expression is higher at stages of neuronal polarization, as judged by reverse-transcription polymerase chain reaction (RT-PCR), and it is mostly cytoplasmic. The tracking of the subcellular localization of Ngn3 in neurons infected with a virus expressing myc-Ngn3 suggests that the protein is quickly translocated to the cell nucleus after synthesis and then reexported to the cytoplasm. Treatment with leptomycin B, a potent and specific inhibitor of the exportin CRM1, induced its accumulation into the nucleus, suggesting that CRM1 mediates the nuclear export of Ngn3. These results suggest that Ngn3 may play a role in neuronal development by actions in the cytoplasm.

In recent years, research on tropical forest conservation has increasingly focused on traditional management systems as a means of achieving a balance between conservation and development. Styrax paralleloneurum , a forest-canopy tree species that produces benzoin, an aromatic resin, is cultivated in such a system. This study is an attempt to determine the impact of benzoin garden management on forest structure, species composition, and diversity. Forty-five gardens were chosen for study in two Northern Sumatra villages, where data on management practices and ecological structure were gathered. Ecological information was also collected from abandoned benzoin gardens and primary forest areas for purposes of comparison. Although benzoin management requires that competing vegetation be thinned, these activities are not intensive, allowing species that coppice to remain in the garden and thereby reducing the effects of competitive exclusion mechanisms on species composition. Tree species diversity in abandoned gardens was similar to that in primary forest, but endemic species and species characteristic of mature habitats were less common. Traditional benzoin garden management represents only a low-intensity disturbance and maintains an ecological structure that allows effective accumulation of forest species over the long term.Jardines de Benjuí en Sumatra Norte, Indonesia: Consecuencias de la Gestión en la Diversidad de Especies Arbóreas § Address correspondence to M. A. Casado, email macasado@bio.ucm.es

Although diversified forest management is promoted as a strategy aimed at slowing tropical deforestation, little is known about the viability of integrating timber and non-timber forest products in the same forest management plans. In this study we offer an initial characterization of multi-purpose tree species in the State of Pará, the principal Amazonian logging region. We identify the species used for both timber and non-timber extraction, and classify these according to their commercial value. We relate multi-purpose species to their ecological traits, the type of non-timber forest use and the fraction of the tree harvested. Although a high number of species present a potential conflict of use, this conflict is only relevant in four of them: D. odorata, T. serratifolia, T. impetiginosa and H. courbaril. Nevertheless, the nature and relevance of this conflict will ultimately depend on the importance that the non-timber use has for the livelihoods of forest-dependant people, the commercial value and the ecological resilience of these species.

In the present study, we describe the temporal and spatial variability in recruitment, growth, and mortality rates of seedlings and saplings of two low-density neotropical tree species, Dipteryx odorata and Copaifera reticulata in Eastern Amazonia, Brazil. As both species have important timber and non-timber uses, for each species we compare regeneration parameters among different management scenarios (sites used for timber logging, nontimber product extraction, and undisturbed forests). Results suggest that both species share similar natural regeneration characteristics. These include temporally and spatially asynchronous germination, existence of individuals that have more abundant and frequent fruit production than the average of the population and a positive influence of the mother tree crown on seedling and sapling density. The management activities analyzed did not influence the regeneration parameters of both species, which suggests that timber logging the way it was performed and current rates of D. odorata seed gathering and C. reticulata tapping at the study site are not sufficiently intense to threaten species population. However, some species characteristics, such as their reproductive strategies, light-demanding syndromes, low-dispersal ranges, and high-mortality rates of seedlings make both species vulnerable to exploitation. (Résumé d'auteur

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