Anatomical characterization of the roots, leaves and culms of Guadua weberbaueri in different growing environments

There has been increasing interest in the use of bamboo for a variety of purposes. In the western Amazon region, specifically in the state of Acre, Brazil, native bamboo (Guadua weberbaueri Pilg.) grows in great abundance, which calls attention to its possible sustainable exploitation. Thus, this project aims to perform the anatomical characterization of the culms, leaves and roots of G. weberbaueri in different environments, both inside and along the border of a forest. For the analysis, samples were collected from culms, leaves and roots at the Zoobotanical Park of Federal University of Acre, and permanent slides were visualized by optical microscopy. We observed that the vascular bundles of the central leaf veins were wider in leaves from the border of the forest than in those from inside the forest. In contrast, the study of root anatomy showed differences in the diameter measurements of the xylem vessel elements, which were larger in those inside the forest than those from the border of the forest. The vascular bundles of culms did not present a difference, although a new characteristic found in this species is described

Similarity analysis of Cedrela sp. trees under different growth conditions in eastern state of Acre, Brazil

A manutenção da dinâmica da biodiversidade em florestas tropicais depende de certo nível de perturbação ambiental, como a queda natural das árvores proporcionando a abertura de clareiras, a germinação das sementes e o crescimento e desenvolvimento das plantas. Por outro lado, o manejo florestal intervém no ciclo natural das florestas pelo corte e retirada das árvores das espécies de maior volume de madeira e de valor comercial. Porém, ainda há pouco conhecimento sobre o crescimento e a regeneração natural das árvores das centenas de espécies tropicais, o que se constitui em uma lacuna e obstáculo para a aplicação do manejo florestal sustentado e, assim, permitindo a manutenção da biodiversidade. Nesse aspecto, esse trabalho visa determinar a idade e a periodicidade do crescimento do tronco do lenho das árvores de Cedrela sp. no estado do Acre, em diferentes condições de crescimento (sítios e microsítios) para propiciar os subsídios ao manejo florestal sustentável. As árvores de Cedrela sp foram selecionadas em três sítios: Reserva Experimental Catuaba (REC) (com três microssítios), Fazenda São Jorge (F. S. Jorge) e Parque Zoobotânico (PZ). Do DAP do tronco das árvores foram retiradas amostras do lenho para as análises dendrocronológicas. Na seção transversal dessas amostras do lenho foi realizada a demarcação, contagem e a mensuração da largura dos anéis de crescimento. Em seguida, utilizando-se o programa Cofecha foi fei- to o controle da qualidade das séries dos anéis de crescimento. Com os parâmetros: número, largura média do anel de crescimento, desvio padrão e o DAP do tronco das árvores foi avaliada a similaridade das árvores de Cedrela sp dos sítios e microssítios, através da análise multivariada. Os resultados indicaram que as condições de crescimento específicas dos sítios e dos ambientes influenciaram significativamente no crescimento radial do tronco das árvores de Cedrela sp demonstrando o potencial da dendrocronologia como ferramenta no manejo florestal.The biodiversity of tropical forests depends on certain level of environmental disturbances, such as the natural fall of trees providing clearings, seed germination, growth and development of plants that environment. On the other hand, forest management intervenes in this natural cycle, by removing larger trees of the species which are of great commercial value. However, little is known about natural growth and regeneration of the hundreds of tropical species; and this constitutes a gap and obstacle to the implementation of sustainable forest management, by permitting the maintenance of biodiversity. In this regard, this study aims to determine the age and growth periodicity of stem of native Cedrela sp. trees in Acre under different growth conditions (sites and microsites) to provide subsidies to sustainable forest management in this region. Trees of Cedrela sp were selected at three sites: Experimental Reserve Catuaba (REC) (three microsites), Farm São Jorge (FSJ) Zoobotanic Park (PZ). Wood samples were collected at DBH of the trunk for the dendrochronological analysis. This was followed by the demarcation, counting and measuring the width of growth rings. Next, the Cofecha program was used for the quality control of the series of growth rings. Using the parameters: number, average width of the growth ring, standard deviation and the DBH of the tree stems, a similarity of trees Cedrela sp. in site and microsites was observed by multivariate statistical analysis.Different growth conditions (sites and environments) significantly affected the radial growth of trees Cedrela sp., demonstrating the potential of dendrochronology as a tool for forest management.Fil: Silveira Lobao, Moises. Universidade Federal Do Acre; BrasilFil: Pereira Ortega, Givanildo. Universidade Federal Do Acre; BrasilFil: Amaral, Edson. Instituto Chico Mendes de Conservação da Biodiversidade; BrasilFil: Gomes Ribeiro Amorim, Patricia. Universidade Federal Do Acre; BrasilFil: Amaro, Marco Antonio. Universidade Federal Do Acre; BrasilFil: Roig Junent, Fidel Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Tomazello, Mario. Universidade de Sao Paulo; Brasi

Variation of wood density and relationship with the tree-ring width of mahogany trees, Swietenia macrophylla, from Amazonian tropical forest of Peru

Mahogany trees, Swietenia macrophylla, occur in open rainforest, semi deciduous and deciduous and dense rainforest of Peruvian Amazonian tropical forest. They occur, preferentially, in areas with a defined dry season, with typical phenology and seasonal variation activity, forming distinct tree-rings. The present work had as aim to determine the wood density radial variation of 14 mahogany trees, of two populations of the Peruvian Amazonian tropical forest, through the X-ray densitometry and to evaluate their application as methodology, compared to the classic method of measurement table, for the determination of the treering width. The radial wood apparent density of the trees profiles rendered it possible to delimit the areas of juvenile-adult wood and of the heartwood-sapwood, relative to the anatomical structure and chemical composition differences, due to the extractives and the vessels obstruction by tyloses. The mean, minimum and maximum wood apparent density of the mahogany trees for the Populations A and B were of 0.70; 0.29; 1.01 g.cm(-3) and 0.81; 0.29; 1.19 g.cm(-3), respectively. The analysis of the variance and mean test indicate differences of mean wood density among the mahogany trees of each population, probably due to the age of the trees. There was no correlation between mean wood density of mahogany trees among the two populations, as well as, between the tree-ring width and the respective mean density. The X-ray densitometry technique is an important tool in the evaluation of the radial variation of wood apparent density and the delimitation of tree-ring boundaries, with correlations of 0.94 and 0.93 in relation to measurement table, for each sampled population