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Qualitative and quantitative descriptions of the woody flora and soil analyses are provided for six areas of montane semideciduous forest in the upper Rio Grande region, southern Minas Gerais, Brazil. Comparisons are made of the floristic composition of these six areas and 24 other forest areas of southeastern Brazil using ordination by detrended correspondence analysis (DCA) and hierarchical classifications, both agglomerative (upgma) and divisive (twinspan). The variation in community structure of five of the six forest areas was analysed using a two-way table yielded by twinspan. The floristic analyses indicated the strongest link between the forests of the upper Rio Grande region and other montane forest formations of southeastern Brazil as well as secondary links with the gallery forests that extend into the cerrado domain and the submontane semideciduous forests of the Rio Parana basin. Variations in community structure among the five forest areas were apparently associated mainly with riverside effects and soil fertility.Descrições qualitativas e quantitativas da flora lenhosa e análises de solos são apresentadas para seis áreas de floresta semidecídua montana na regiāo do alto rio Grande, sul de Minas Gerais, Brasil. Sāo feitas comparações florísticas das seis florestas e de outras 24 áreas de floresta do sudeste brasileiro usando ordenação por análise de correspondência (DCA) e classificações hierárquicas, tanto aglomerativa (upgma) como divisiva (twinspan). As variações em estrutura comunitária de cinco das seis florestas foram analisadas usando uma tabela bidirecional produzida por twinspan. As análises florísticas indicaram uma ligação mais forte entre as florestas do alto rio Grande e outras formações florestais montanas do sudeste do Brasil, bem como laços florísticos secundários com as florestas de galena que penetram o domínio dos cerrados e com as florestas semidecíduas submontanas do vale do rio Paraná. As variaç˜es em estrutura comunitária entre as cinco florestas mostraram-se aparentemente associadas principalmente com o efeito da margem dos rios e com a fertilidade dos solos.

RESUMO – (Variacoes floristicas e estruturais do componente arboreo de uma floresta ombrofila alto-montana as margens do rioGrande, Bocaina de Minas, MG, Brasil). Realizou-se o levantamento da comunidade arborea de uma floresta ombrofila alto-montanasituada nas vertentes interiores do macico do Itatiaia, em Bocaina de Minas, MG (22°13’S; 44°34’W, altitude 1.210 a 1.360m), co m oproposito de avaliar as correlacoes entre variacoes estruturais e variaveis ambientais relacionadas ao substrato. Foram analisadosaspectos da estrutura fisionomica (densidade, area basal e distribuicao de tamanhos das arvores) e comunitaria (composicao, dis tribuicaoe diversidade de especies). Foram alocadas 26 parcelas de 20×20m para amostragem dos individuos arboreos com diâmetro a altura dopeito (DAP) ≥ 5cm, onde tambem foram coletados dados topograficos e amostras de solo superficial para analises quimicas e texturais.Foram registrados 2.574 individuos, 221 especies, 120 generos e 54 familias, bem como tres subgrupos de solos: Latossolos Amare los,Latossolos Vermelho-Amarelos e Latossolos Vermelhos, distribuidos sequencialmente da baixa para a alta encosta. A comunidade ar boreacorrespondeu ao perfil floristico e fisionomico das florestas alto-montanas do Sudeste brasileiro, diferenciando daquelas de menoresaltitudes da mesma regiao. Uma analise de correspondencia canonica detectou um gradiente de distribuicao das especies arboreassignificativamente correlacionado com variacoes do substrato ao longo da encosta do morro. Houve ainda variacoes significativas entre ostres habitats de solo quanto a diversidade de especies, mas nao para a densidade e area basal das arvores e para as distribuico es de alturae diâmetro. O regime de agua no solo foi provavelmente a variavel ambiental chave, relacionada com as variacoes floristicas e e struturaisda floresta.Palavras-chave: Floresta ombrofila alto-montana, comunidade arborea, diversidade de especies, variaveis ambientaisABSTRACT – (Structural and floristic variations of the arboreal component of a tropical upper montane rainforest on the margin of theRio Grande, Bocaina de Minas, Brazil). The tree community of an area of upper montane rain forest situated on the interior moun tain-side of the Itatiaia Range, Brazil (22°13’S 44°34’W, altitude 1,210 to 1,360m), was surveyed with the purpose of assessing thecorrelations between their structural variations and environmental variables related to the substratum. Variations were analyzed forphysiognomic structure (tree density, basal area and size distribution) and community structure (species composition, distribut ion anddiversity). Individual trees with diameter at breast height (dbh) ≥ 5cm were surveyed within 26 plots of 20×20m of dimensions wheretopographic data and samples of surface soil were also collected, the latter for chemical and textural analyses. The survey tot aled 2,574individual trees, 221 species, 120 genera and 54 families, as well as three soil classes: Yellow Latosols, Red-Yellow Latosols, and RedLatosols, distributed sequentially from the slope base to the hilltop. The tree community corresponded to the floristic and phy siognomicfeatures of the upper montane forests of southeastern Brazil, differing from those of lower altitudes in the same region. A canonicalcorrespondence analysis detected a main gradient of tree species distribution significantly correlated with variations of the s ubstratumalong the hill-slope. There were also significant variations among the three soil habitats for species diversity but not for tr ee density andbasal area and for height and diameter distributions. Ground water regime was probably the key environmental variable related t o thefloristic and structural variations of the forest.Key words: Tropical upper montane rainforest, tree community, species diversity, environmental variables

The interrelationships between the distribution of woody species and environmental variables were investigated in an area of deciduous dry forest in Santa Vitoria, central Brazil. This is the first study of a vanishing type of dry forest which grows on base-rich soils originating from the basalt bedrocks of southern Goias and western Minas Gerais. A survey of topography, soil properties, canopy gaps and woody plants (≥5 cm diameter at the base of the stem) was conducted in 50–15 × 15 m quadrats. The soils were classified into the following soil series: Hapludolls Haplustolls Haplustolls Ustropepts Rhodustalfs. This series corresponded to a gradient of increasing elevation and effective soil depth and decreasing slope gradient, soil organic matter and total exchangeable bases. A canonical correspondence analysis and a detrended correspondence analysis indicated that plant species’abundance distribution was significantly correlated with both the relative area of canopy gaps in the quadrats and the soil-topography gradient. Presumably, the critical factors involved in these two gradients are, respectively, light and ground water regimes. The influence of canopy gaps (i.e., light) was surprising and has not been documented previously for tropical deciduous dry forests. RESUMO As interrelacoes entre a distribuicao de especies lenhosas e variaveis ambientais foram investigadas em uma area de floresta seca decidua em Santa Vitoria, Minas Gerais. Este e o primeiro estudo sobre as florestas deciduas que crescem sobre os solos ricos em nutrientes derivados dos derrames basalticos do sul de Goias e Triângulo Mineiro e que foram quase erradicadas da regiao. Foi realizado um levantamento da topografia, propriedades dos solos, clareiras e plantas lenhosas (≥5 cm de diametro na base do tronco) em 50 parcelas de 15 × 15 m. Os solos foram classificados na serie Hapludolls Haplustolls Ustropepts Rhodustalfs, a qual corresponde a um gradiente crescente em elevacao topografica e decrescente em profundidade efetiva do solo, declividade do terreno, materia orgânica do solo e soma de bases trocaveis. Uma analise de correspondencia canonica e uma analise de correspondencia retificada indicaram que a distribuicao da abundância das especies lenhosas correlacionou-se significativamente com a area relativa de clareiras nas parcelas e com o gradiente de solos e topografia. Presumivelmente, os fatores criticos envolvidos nestes dois gradientes foram, respectivamente, luz e regime de agua no solo. A influencia de clareiras (ou seja, luz) foi surpreendente e nao tinha sido documentada anteriormente para florestas deciduas secas.

Summary The relationships between topography, soil taxonomic categories and tree species distribution were analysed in a riverside semideciduous forest on the margins of the Rio Grande, in Conquista, state of Minas Gerais, Southeastern Brazil. The forest was sampled by two transects made up of 50 contiguous 15 × 15 m2 quadrats (total 1.125 ha). Each transect started at the river margin and extended upslope so that they could include two soil catenas: the first with the sequence Ustifluvent, Haplustox and Ustorthent, and the second with Ustifluvent followed by Haplustult. A quick but more extensive survey was carried out in the whole forest fragment covering the same soil habitats in order to assess the extension of soil-species relationships found in the transects. A canonical correspondence analysis indicated that the species’ abundance distribution was significantly correlated with the soil habitats. Differences in soil drainage classes among the soils rather than their chemical properties appeared to be the leading factor: tree species distribution was strongly correlated with a wide hydrosequence ranging from poorly drained to strongly drained soils. The 55 most abundant species were classified according to their ecological group (regeneration guild) within the forest dynamics. A tentative ecological classification of those species combining their habitat preference in terms of soil drainage class and their growth strategy suggested that these factors play and important role in promoting the coexistence of tree species in that type of forest.

Summary The differences in plant community structure and soil properties between streamside and upland topographical sites were analysed in an area of montane semideciduous forest on the margins of the Camargos Reservoir, southeastern Brazil. The studied forest patch lies at the headwaters of two narrow streams and is surrounded by montane grasslands. The plant community was surveyed by one 30 × 150 m and one 30 × 165 m transects, both made up of 15 × 15 m contiguous quadrats. The first transect extended along one of the streams while the other linked the two streams by traversing the interfluve. Soil samples were collected from all quadrats and their texture and chemical properties were analysed in the laboratory. The streamside soils were tropical Podzolic Soils, characterised by clay depletion of the top layer with its accumulation in the deeper horizons. The upland soils were Cambisols, a 'maturing' soil type with no clear zonation. A canonical correspondence analysis indicated that the species' abundance distribution was significantly correlated with the two topographical sites as well as with some soil properties. The most abundant species appeared to vary from fairly exclusive streamside or upland preferentials to broadly indifferent for the two habitats. A tentative ecological classification of the 69 most abundant species according to their preference for streamside or upland habitat and to their growth strategy in the forest dynamics, is presented. An overall analysis of this classification along with the differences in soil properties between the two topographic sites gives evidence that the forest probably expanded from the two valley bottoms towards the upland sector occupying sites that were previously covered with montane grasslands.

The relationships between soil properties, topography and tree species distribution were analysed in a tropical riverine forest at the margins of the Rio Grande, in Bom Sucesso, state of Minas Gerais, south-eastern Brazil. The forest was sampled by three 0.18 ha plots, with each plot made up of eight contiguous 15 m X 15 m quadrats, four of which were placed at the river margin and the remaining four in the forest interior. A canonical correspondence analysis indicated that the species' density distribution was significantly correlated with some soil chemical characteristics and topographical features. The soils of the three sample plots showed statistically significant differences for the levels of Ca, Mg, K and pH, with the fertility (expressed by the cation exchange capacity) increasing from Plot I to Plot III. These variations were mainly explained by the first canonical axis while the second was strongly correlated with topographical variables, separating the quadrats into two groups: those of the higher and steeper sites from those of the lower sites. The only soil property that was significantly different in lower and upper sites was the concentration of phosphorus. No significant difference in tree species distribution was found between river margin and interior quadrats, certainly because this forest sector lies on the outer side of a curve of the river where erosion is currently building high and steep river banks and forcing the forest to retreat. A tentative ecological classification of the 30 most abundant species according to their habitat preference in terms of soil fertility and topographical sites, and to their growth strategy in the forest dynamics, is presented. It is suggested that these factors play an important role in promoting the coexistence of tree species in this type of forest.

The interrelationship between river flooding regime, topography, soil properties and the distribution of tree and bamboo species was analysed in an area of tropical semideciduous forest on the margins of the Rio Grande, in Madre de Deus de Minas, Southeastern Brazil. A survey was carried out in a single forest plot (1.597 ha, 71 adjacent 225 m2 quadrats) located in the inner side of a river bend and extending from the point bar to the top of the slope. All trees (≥5 cm diameter at the base of the trunk) and bamboo culms were registered. Soil samples were collected and analysed for their properties and the river level was monitored during a two year period. In the point bar the forest was dominated by only two tree species, Salix humboldtiana and Inga affinis, that tended to occur in distinct areas. Differences in soil properties between these areas suggest variation in sedimentation dynamics. In the sloping part of the plot, a canonical correspondence analysis (CCA) indicated that the floristic composition was significantly correlated with three topographic sectors and their corresponding flood regimes. The Lower Slope corresponds to the sharp transition to the point bar forest, endures partial and annual floods and shows a very distinct flora that includes many light-demanding species. The Middle Slope is only occasionally reached by exceptional river floods and is characterised by a high density of the bamboo Merostachys neesii. The comparatively low density and basal area of trees, particularly for the smaller ones, provide evidence that the bamboos are problably interfering with the trees by restricting their recruitment. The Ridgetop lies entirely above the highest flooding level registered. The density of bamboos is lower and the understorey trees abundant.

Two adjacent tracts of tropical secondary forest, situated in Itambe do Mato Dentro, south-eastern Brazil, which had been regenerating for 15 and 40 years after clearing, were compared with the purpose of detecting differences in species diversity and composition, species guild composition (regeneration, stratification and dispersion), and stand structure. Four and three 1,125 m2 plots laid on the 15- and 40-year-old stands, respectively, sampled 2,430 trees with diameter at the base of the stem > 5 cm. The number of species (S = 199) was high for this forest type and significantly higher for the older stand. Tree density was significantly higher in the younger stand, particularly for smaller trees, whereas the two stands did not differ in both basal area and volume per hectare. Trees of shade-tolerant and understory species were significantly more abundant in the older stand. Though sharing a large proportion of species (49%), the two stands differed significantly in the abundance of many species. Live stumps probably contributed to the relatively quick restoration of some forest characteristics, particularly species diversity, basal area and volume.

Realizou-se o levantamento florístico e fitossociológico da comunidade arbórea de um fragmento de Floresta Estacionai Semidecidual Sub-Montana localizado às margens do reservatório da usina hidrelétrica Dona Rita, situado na Fazenda Camarinha, em Itambé do Mato Dentro, MG, na bacia do rio Doce (19º26'S, 43º 14' W, altitude entre 610 e 630m). Todos os indivíduos com diâmetro do caule à altura do solo > 5,0cm (exceto lianas) encontrados em 35 parcelas de 15xl5m (0,78ha) foram identificados, medidos e tiveram sua altura estimada (também foram coletados indivíduos que se apresentavam com estruturas reprodutivas, fora das parcelas). Foram estimados para cada espécie os seguintes parâmetros: densidade por área, freqüência absoluta, dominância absoluta e índice de valor de importância (IVI). Também foram calculados o índice de diversidade de Shannon e a equabilidade correspondente, o índice de similaridade de Jaccard e as distâncias euclidianas quadradas entre esta floresta e outras do alto e médio Rio Grande, baixo Paranaíba e alto São Francisco. Nas parcelas foram amostrados 2.430 indivíduos. Identificou-se 216 espécies (15 fora das parcelas) pertencentes a 50 famílias e 144 gêneros. Destacam-se pelo IVI as famílias Euphorbiaceae, Myrtaceae e Caesalpiniaceae e as espécies Apuleia leiocarpa, Pera glabrata, Licania hypoleuca e Mabeafistulifera. Comparada com algumas florestas ciliares do Estado, a floresta de Itambé do Mato Dentro se assemelha mais com a do alto Rio Grande (ambas localizadas em regiões sob influência da Mata Atlântica), muito embora as espécies mais importantes não sejam as mesmas. Em termos pedológicos a floresta de Itambé apresenta os solos mais intemperizados, lixiviados e profundos, apesar de seu relevo íngreme, devido ao material constitutivo dos mesmos ter sofrido intenso processo de alteração anterior ao atual ciclo pedogênico. A floristic and phytosociological survey of the tree commnunity was carried out in a fragment of sub-montane semideciduous forest located on the margin of the Dona Rita Hydroelectric Reservoir, municipality of Itambé do Mato Dentro, State of Minas Gerais, south-eastern Brazil (19º26'S, 43º14'W, 610-630m of altitude). All individuals with a stem diameter at the base, of dbt > 5cm (lianas excepted) found in thirty five 15x15m quadrats, were identified, measured (dbt) and had their height estimated (individuals found outside quadrats with reproductive structure were also collected). The following phytosociological parameters were calculated for all species: density per area, absolute frequency, absolute dominance calculated from the basal area, and importance value. The Shannon diversity index and the corresponding evenness were calculated. Jaccard's similarity indices and euclidian distances were also calculated among the studied forest and other forests surveyed in the following regions of Minas Gerais State: Upper and Mid Rio Grande, Lower Rio Paranaiba and Upper Rio São Francisco. A total of 2,430 individuals were recorded in the sample area. These belonged to 50 families, 144 genera and 216 species. The following families produced the highest importance values: Euphorbiaceae, Myrtaceae and Caesalpiniaceae. The most important species were Apuleia leiocarpa, Pera glab rata, Licania hypoleuca, and Mabeafistulifera. A comparison with the other areas indicated that the forest of Itambé do Mato Dentro is more similar to those of the Upper Rio Grande which are all under a stronger floristic influence of the Atlantic Forest, although the most important species are not the same. The soils of the area are deeper, highly weathered and leached, despite the strongly sloping topography because they had gone through an intense process of alteration prior to the present pedogenetic cycle.

Realizou-se o levantamento das espécies com diâmetro ao nível do solo > ou = 5,0 cm na mata da Fazenda dos Botelhos, em Bom Sucesso, localizada às margens do Rio Grande, no Sul de Minas Gerais, com o objetivo de reconhecer espécies nativas a serem utilizadas na revegetação das margens de rios e represas da região. Identificaram-se 245 espécies pertencentes à 65 famílias botânicas. São apresentadas comparações florísticas com matas do estado de São Paulo. A floristic survey was carried out in a riparian forest of the Rio Grande in Bom Sucesso, Minas Gerais, Brazil, considering the species of trees and shrubs with diameter at the base of the stem > or = 5 cm. The purpose was to produce a list of indigenous species for potential use in environmental rehabilitation programs that have bee carried out on the margins of rivers and dams of this region. A list is provided with 245 species of 65 botanic families. Floristic comparisons are made with florests surveyed in the State of São Paulo.

A floristic survey was carried out in an 9.450m2 fragment of riparian forest on the margin of the hydroelectric reservoir of Camargos, Itutinga, state of Minas Gerais, SE Brazil. All individuals with minimum diameter at the base of stem 5cm were surveyed in the sampled area forest. A list is provided with 253 species of trees and shrubs belonging to 66 botanic families. Floristic similarity indices were calculated in comparisons with other floristic surveys of forest in the states of Sao Paulo and Minas Gerais.