Scaling of stem and crown in eight Cecropia (Cecropiaceae) species of Brazil

The scaling of stem and crown was studied in eight Cecropia species in Amazonian and southeastern forests of Brazil. The Amazonian species, C. concolor; C. palmata, C. purpurascens, C. sciadophylla, and C. ulei were studied in Manaus, Amazonas, Brazil. The southeastern species, C. glaziovii, C. hololeuca, and C. pachystachya were studied in Linhares, Espirito Santo, Brazil. Measures of diameter, height, number of branches, number of leaves, and total leaf area were log transformed and regressed on height. Three models of mechanical designs of trees, elastic, constant stress, and geometric similarity, were tested for Cecropia. None of the models can totally describe Cecropia, but geometric similarity was a close approximation. Most of the species did not vary in diameter-height relationships between unbranched and branched individuals. Safety factors diminished with height in most species studied. The crown-height relationships were similar for all species. Numbers of branches and leaves showed some variation among species and are related to height of first branching. Total leaf area had a constant allometric relationship among species, although regression intercepts differed according to species leaf areas. The scaling relationships of stem and crown in Cecropia varied with adult size of the studied species.88593994

Architectural patterns of eight Cecropia (Cecropiaceae) species of Brazil

Architectural patterns of eight Cecropia species were studied in Amazonian and Southeastern Brazil. Height, diameter, height of first branching, number of branches and leaves, leaf area, internode length and branching ratio were measured for undamaged trees. The Amazonian species C. concolor; C. palmata, C. purpurascens, C. ulei and C. sciadophylla were studied in Manaus. Cecropia galziovii, C. hololeuca and C. pachyshachya were studied in Linhares, Espirito Santo. All except C. hololeuca and C. sciadophylla are myrmecophytes. In both areas, size and architectural characters are displayed as a gradient from open habitats to forest. Cecropia hololeuca and C. sciadophylla are common in forests and had similar architectures, with low branching ratios, and a height of first branch of around 9 m, about 3 m higher than the other species. The branching pattern of both species and the maximum height recorded (approximate to 20-25 m respectively) allow them to remain in the canopy longer than the other Cecropia species. Cecropia concolor and C. pachystachya measure up to 13 m in height and are typical of open habitats. The remaining species occupy forest margins and are intermediates between these two extremes.196321522

Estoque e frações de carbono orgânico e fertilidade de solo sob floresta, agricultura e pecuária

O entendimento dos fenômenos de trocas de carbono entre solo, água e atmosfera é fundamental para o manejo e a conservação de ecossistemas naturais e agrários. Os objetivos deste trabalho foram determinar os estoques de carbono orgânico, as suas frações e a fertilidade do solo sob os manejos florestal (mata remanescente), integrando agricultura e florestas (eucalipto e cutieira) e em monoculturas agrícola (sob pivô central) e pastoril (braquiária), na Bacia do Rio Paraopeba, em Florestal-MG, visando a propor indicadores para a avaliação de manejo e conservação do solo. As amostras de solo foram coletadas em remanescente de mata nativa (Mata), em área agrícola cultivada sob irrigação de pivô central (Pivô) e em áreas de cultivo de Corymbia citriodora (Corymbia citriodora (Hook.) K.D. Hill & L.A.S. Johnson) (Eucalipto), Joannesia princeps Vell. (Cutieira) e Brachiaria decumbens Stapf (Pasto), nas profundidades de 0 a 20 e 20 a 40 cm. Os resultados indicaram que as estimativas dos estoques e de estabilidade do carbono orgânico aumentaram com a fertilidade do solo. Os sistemas florestais, principalmente a Mata, acompanhada pelos sistemas de manejo do solo integrando florestas à pastagem, em comparação com o cultivo contínuo ou a monocultura de pastagem, apresentaram estoques de carbono maiores, mais estáveis e menos solúveis, com formas mais aromáticas e hidrofóbicas (maior relação AH/AF), indicando menor potencial de lixiviação de carbono para o sistema aquático adjacente

Colobura dirce dirce

The Atlantic Forest biome includes the middle region of the Zona da Mata (MRZM) in southeastern Minas Gerais, Brazil. Cecropia hololeuca Miq. (Rosales: Urticaceae) is an arboreal plant endemic to Brazil. Species of Colobura Billberg (Lepidoptera: Nymphalidae) are common in forested habitats in the Neotropical Region. The aims of this study were to report damage by C. dirce dirce L. larvae on C. hololeuca in the MRZM, and to review host plants of Colobura spp. Two hundred fifty-two larvae were found damaging twenty 50 cm tall C. hololeuca plants on the campus of the “Universidade Federal de Viçosa” in Viçosa, Minas Gerais, Brazil, and brought to the “Laboratório de Controle Biológico de Insetos (LCBI).” Adults and exuviae of these larvae were deposited at the LCBI and identified in the “Departamento de Zoologia” of the “Universidade Federal do Paraná” in Curitiba, Paraná, Brazil, as C. dirce dirce. This is the first report of this lepidopteran on C. hololeuca in the MRZM. Seventeen species from 6 plant families have been reported as hosts for C. dirce dirce.O bioma Mata Atlântica inclui a região média da Zona da Mata, na parte sudeste de Minas Gerais, Brasil. Cecropia hololeuca Miq. (Rosales: Urticaceae) é uma planta arbórea endêmica ao Brasil. Espécies de Colobura Billberg (Lepidoptera: Nymphalidae) são comuns em habitats florestais na região Neotropical. Os objetivos deste estudo foram relatar danos causados por lagartas de C. dirce dirce L. sobre C. hololeuca na região média da Zona da Mata e revisar as plantas hospedeiras de Colobura spp. Duzentas e cinquenta e duas lagartas foram encontradas danificando vinte plantas de 50 cm de altura de C. hololeuca no campus da Universidade Federal de Viçosa, em Viçosa, Minas Gerais, Brasil, e trazidas para o LCBI. Adultos e exúvias dessas lagartas foram depositadas no Laboratório de Controle Biológico de Insetos (LCBI) e identificados no Departamento de Zoologia da Universidade Federal do Paraná, em Curitiba, Paraná, Brasil, como C. dirce dirce. Este é o primeiro relato deste Lepidoptera sobre C. hololeuca na região média da Zona da Mata. Dezessete espécies de seis famílias de plantas têm sido relatadas como hospedeiras de C. dirce dirce