Doádi Antônio Brena

Estrutura e padrões de distribuição espacial de espécies arbóreas em uma amostra de Floresta Ombrófila Mista em Nova Prata, RS.

Normal 0 21 MicrosoftInternetExplorer4 Este estudo objetiva descrever a estrutura da vegetacao e os padroes de distribuicao espacial das especies arboreas e arvoretas de uma amostra de um hectare de Floresta Ombrofila Mista, localizada no municipio de Nova Prata, estado do Rio Grande do Sul. Utilizando o metodo de area fixa, foram instaladas vinte unidades amostrais de 10 x 50 m (500 m²), perfazendo uma amostra de 100 x 100 m (10000 m 2 ) e mensurados todos os individuos com DAP ³ 9,6 cm (30 cm de circunferencia), que compoem o dossel da floresta. A amostra de vegetacao estudada apresentou uma diversidade mediana de especies arboreas e arvoretas (55 especies com DAP ³ 9,6 cm) e uma elevada densidade de individuos por hectare (848 ind./hectare), similares aos encontrados em florestas secundarias, no dominio da Floresta Ombrofila Mista. A vegetacao, na amostra, apresentou-se com maior proporcao de especies com distribuicao agregada ou com tendencia a agregacao (46,7 %), revelando que as maiores populacoes arboreas formam pequenas manchas ou agrupamentos na vegetacao, com maiores valores obtidos para a Razao Variância/Media. Este estudo, mesmo se tratando de uma analise em pequena escala espacial (10000 m²), destaca a densidade e a distribuicao das especies arboreas a arbustivas em um trecho de floresta que sofreu exploracao comercial, fragmentos importantes das florestas atuais do estado do Rio Grande do Sul, Brasil.

Estrutura da regeneração natural em Floresta Ombrófila Mista na Floresta Nacional de São Francisco de Paula, RS

The aim of this paper was to characterize the natural regeneration through the analysis of the phytossociological structure, in a Mixed Rainy Forest at Sao Francisco de Paula National Forest (between 29°23’ and 29°27’ S and 50°23’ and 50°25’ W), as a way of providing information regarding the recovery and conservation of these ecossistems, and describing the possibilities of future use of the natural regeneration. There have been sampled 180 subunits of 100 m² (10 x 10 m) where there were measured the total heigth (h) of the individuals with h ³ 1,30m, with minimum circumference of 3,0 cm, up to a maximum of 30,0 cm. The total density was 7.984 individuals/ha, belonging to 109 species, 88 genera and 46 botanical families, besides dead individuals, lianas and no-identified species, with index of diversity of Shannon-Weaver (H’) of 2.22. The most important specie were Casearia decandra , Stillingia oppositifolia and Sebastiania brasiliensis . The Araucaria angustifolia in spite of being the outstanding physiognomic and the larger economical interest species of the Rain Forest, presented low values in all the evaluated parameters, needing forestation treatment and enrichment plantation that would specially benefit the development of its regeneration.

Florística e classificação da regeneração natural em Floresta Ombrófila Mista na Floresta Nacional de São Francisco de Paula, RS

This work aims at evaluating a methodology in order to estimate the volume of wood in the forest inventory considering the stem taper quality of trees. A stand of 4.31 ha was used with an area planted with Eucalyptus sp. with sixteen years-old, originated from seminific propagation. The initial spacing used in the planting was 3 m x 3 m, being made a selective thinning at 8.6 years-old. Eight circular samples of 855 m 2 were located. In those samples, the diameter in the height of 1.30 m ( DBH ) and the total height ( HT ) of the trees were measured, being the tree stems DBH larger than 28 cm classified in agreement with a priori defined quality classes. The tree stems of the eight samples were submitted to the optimization process. After the crop of all trees, the stems were marked by a trained team and were sawed to subsequent comparison to commercial volume obtained by the optimization method. The volume and the number of logs for quality classes and assortment, optimized and harvested, differed significantly from the qui-square test to 5% of probability. It was concluded that it is needed standardization of the exploration and inventory team training, and the presented inventory methodology should be improved before implementation.

DIVERSIDADE E CLASSIFICAÇÃO DA COMUNIDADE ARBÓREA DA FLORESTA OMBRÓFILA MISTA DA FLONA DE SÃO FRANCISCO DE PAULA, RS

This study aims to describe the diversity and the arboreal community classification of the Ombrophylous Moist Forest located at FLONA in Sao Francisco de Paula, RS, using floristic and hierarchical analysis data through the TWINSPAN (Two-way Indicator Species Analysis) program. It had been used ten portions of 1 hectare each one and it had been distributed at FLONA’s area in a randomnly way. In each 1 hectare conglomerate all individuals with DAP ≥ 30 had been measured. The encountered species diversity is within the limits that had been described for Ombrophylous Moist Forest in the South of Brazil, with estimates varying from 75 to 110 arboreal species. The TWINSPAN method had determined three great floristic groups: Group 1 – Araucaria association, showing Araucaria angustifolia (Betol.) Kuntze as the indicative species; Group 2 – Sebastiania association, presenting as indicative species Sebastiania commersoniania (Baill.) L. B. Sm. et Downs, Sebastiania brasiliensis Spreng. and Cryptocarya aschersoniana Mez and Group 3 – Podocarpus association, presenting as indicative species Podocarpus lambertii former Klotzsch Endl.

Classificação e crescimento de unidades de vegetação em Floresta Ombrófila Mista, São Francisco de Paula, RS.

This work was developed with the objective of studying the present ecological groups in the Mixed Rainy Forest and of describing the composition and the growth dynamics during the four seasons. The work had been accomplished in ten permanent conglomerates of 1 ha (100m x 100m), which were divided into ten strips of 10m x 100m (1000m 2 ) and these ones subdivided into ten subunits of 10m x 10m (100m 2 ). In this research, one 10m x 100m strip in conglomerate was selected, totaling ten subunits, where it had been installed, at BHD height, dendrometric bands in all trees with CBH ≥ 30 cm, to verify the annual and the seasonal growth. The density per species formed a matrix (99 x 39) used to test vegetation grouping through TWINSPAN (Two-way indicator species analysis), since three ecological groups were verified. Group 1 was denominated primary forest; group 2, humid site forests, and group 3, secondary forest. ≥ 30 cm. The annual average increment was larger for the primary forest, following the secondary forest and the forest of humid places. In decreasing order, the average periodic increment was larger in the summer, spring, autumn and winter. The species that stood out in density terms and increment were Cupania vernalis and Nectandra megapotamica .