Aim: Tropical forests account for a quarter of the global carbon storage and a third of the terrestrial productivity. Few studies have teased apart the relative importance of environmental factors and forest attributes for ecosystem functioning, especially for the tropics. This study aims to relate

1. Forests account for a substantial part of the terrestrial biomass storage and productivity. To better understand forest productivity, we need to disentangle the processes underlying net biomass change. 2. We tested how above-ground net biomass change and its underlying biomass dynamics (biomass recruitment, growth and mortality) can be explained by four alternative and contested hypotheses; the soil fertility, biomass ratio, niche complementarity and vegetation quantity hypotheses. 3. Above-ground biomass dynamics were evaluated over a 5-year period in 200 permanent sample plots in 8 tropical dry forests in Brazil, and related to soil fertility, community-weighted mean (CWM) traits that are important for carbon storage and sequestration (wood density, specific leaf area, maximum stem diameter and deciduousness), species richness, functional diversity and initial stand biomass. 4. Initial stand biomass was the best predictor of all three processes of biomass dynamics, providing strong support for the vegetation quantity hypothesis. In these dry forests, the dominance of conservative species, rather than of acquisitive species, is associated with high biomass growth and storage, probably because their low specific leaf area and high wood density allow them to keep on functioning during drought stress. 5. Paradoxically, high soil fertility (Ca) led to low biomass productivity, probably because of nutrient imbalance. 6. In contrast to what is shown for controlled experiments, we found no support for niche complementarity (in terms of functional diversity or species richness) for forest productivity. Biomass storage was favoured by low-rather than high trait diversity, as most of the biomass is concentrated in species with large stem diameter and high wood density. 7. Synthesis. Biomass dynamics are mainly shaped by vegetation quantity, and then by vegetation quality, in line with the mass ratio hypothesis. Dry forests show different trait-productivity relationships than wet forests, as stands with 'slow' trait values are 'fast' in terms of productivity. Diversity matters, but in a different way than expected; high trait diversity does not enhance productivity, but instead, does low trait diversity enhance carbon storage.

-(Functional morphology and ecology of tree species seedlings of the Ecological Station of Panga, Uberlândia, Minas Gerais). The seedling functional morphology classification was used to study 122 tree species occurring at the Ecological Station of Panga, Uberlândia, Minas Gerais. The tree species of three contiguous forest formations -gallery forest, semideciduous forest and "cerradão" -had their seedlings classified according to the position, texture and cotyledon exhibition. This study intended to verify if all the studied species would fit in a functional morphology classification system and if seedling morphology would have any relation with some ecological traits, such as successional group, type of dispersal, fruiting period, seed weight, habitat, sexual system, and root/stem biomass allocation. The species were subdivided into five categories: 63 species of the phanero-epigeal-foliaceous type (PEF), 20 phanero-epigeal-reserve type (PER), 10 phanero-hypogeal-reserve type (PHR), 28 crypto-hypogeal-reserve type (CHR) and only one species of the crypto-epigeal-reserve type (CER). The classification used was very effective, representing almost all the studied species. There were no significant relationships between functional morphology groups and type of dispersal, fruiting period, root/stem biomass or micro-habitat. On the other hand, significant relationships were found between successional groups, seed weight and sexual systems with seedling functional morphology categories. Pioneer species, mostly with small and light seeds, presented almost exclusively PEF seedlings, while shade tolerant climax species, which usually produce fewer and larger seeds with plenty of reserves, showed mostly CHR seedlings. This seedling type prevails also among the dioecious species. The results demonstrated that morphology has, at least in early stages, a determinant role in the processes of tree seedling establishment and development.Key words -cerrado, cotyledons, ecology, establishment, seedling RESUMO -(Ecologia morfofuncional de plântulas de espécies arbóreas da Estação Ecológica do Panga, Uberlândia, Minas Gerais). Realizou-se a classificação morfofuncional de plântulas de 122 espécies arbóreas da Estação Ecológica do Panga. Espécies de três formações florestais contíguas -mata de galeria, mata mesófila semidecídua e cerradão -tiveram suas plântulas classificadas segundo suas características cotiledonares de posição, textura e exposição. O estudo objetivou verificar se as espécies estudadas enquadravam-se no sistema de classificação utilizado e se existiria alguma relação entre os tipos morfofuncionais de plântulas com grupos sucessionais, síndrome de dispersão, peso das sementes, micro-habitat, sistemas sexuais, épocas de frutificação e relação entre a biomassa de raízes e partes aéreas. As espécies foram incluídas em cinco categorias, sendo 63 espécies do tipo fanero-epígeo-foliáceo (PEF), 20 fanero-epígeo-armazenador (PER), 10 fanero-hipógeo-armazenador (PHR), 28 cripto-hipógeo-armazenador (CHR) e apenas um...

We examined floristic patterns of ten seasonal semideciduous forest sites in southeastern Brazil and conducted a central sampling of one hectare for each site, where we took samples and identified all individual living trees with DBH (diameter at breast height, 1.30 m) ≥4.8 cm. Arboreal flora totaled 242 species, 163 genera, and 58 families. Fabaceae (38 species) and Myrtaceae (20 species) were families with the largest number of species. OnlyCopaifera langsdorffiiandHymenaea courbariloccurred at all sites. Multivariate analysis (detrended correspondence analysis and cluster analysis) using two-way indicator species analysis (TWINSPAN) indicated the formation of a group containing seven fragments in whichSiparuna guianensiswas the indicator species. This analysis revealed that similarities between studied fragments were due mainly to the successional stage of the community.

-(Relationship between tree species distribution and topography in a forest gradient in the Panga Ecological Station (Uberlândia, MG)). This research aimed to characterize the topography and to assess its relationship with the distribution of the 20 most abundant tree species sampled on a forest gradient (gallery, semideciduous forest and "cerradão") in the Ecological Station of Panga, municipality of Uberlândia, Minas Gerais, Brazil. Using a level tube, the differences in topographic levels were measured between points of 211 plots situated in eight transects. The forest gradient occurs on a predominantly convex slope, facing Northeast, with inclination ranging from about 4% on the top to more than 40% on lateritic outcrops at the bottom. The overlay of topographic and species distribution maps showed that species may be or are dependent, tolerant or intolerant to different levels of soil hydric saturation related to variations of topography. Other species showed association to edaphic factors and/or light condition at the forest edges or in gaps.RESUMO -(Relação entre distribuição de espécies vegetais arbóreas e topografia em um gradiente florestal na Estação Ecológica do Panga (Uberlândia, MG)). Objetivou-se caracterizar a topografia da área estudada e avaliar sua relação com a distribuição das 20 principais espécies arbóreas amostradas em um gradiente florestal (galeria, mesófila semidecídua de encosta e cerradão), na Estação Ecológica do Panga, município de Uberlândia, Minas Gerais, Brasil. Utilizando-se mangueira de nível, foram medidos os desníveis entre pontos de 211 parcelas distribuídas em oito transectos. O gradiente florestal situase sobre uma vertente predominantemente convexa, voltada para Nordeste, com inclinação de cerca de 4% no topo até mais de 40% sobre rochas na base da formação. A sobreposição de mapas (distribuição das espécies e topográfico) mostrou que algumas das espécies são influenciadas positiva ou negativamente às variações de umidade do solo ocasionadas pela topografia ocorrentes na mata de galeria, enquanto que outras mostram relação com outros fatores edáficos e/ou condições de luminosidade de bordas e clareiras.