Ângelo Augusto Ebling

Prognose da Estrutura Diamétrica em Floresta Ombrófila Mista / Prognosis of Diameter Structure in a Mixed Ombrophyilous Forest

This study aimed to evaluate the accuracy of diameter projections, using the transition matrix and movement ratio models in different temporal amplitudes and diameter class intervals, for a Mixed Ombrophyilous Forest fragment located in the municipality of Sao Joao do Triunfo, Parana state. The data were collected from a continuous inventory that has been carried out in a 3.5 ha sampling area since 1995. The data collected between 2000 and 2005 were divided into classes of 5 cm and 10 cm and grouped into four temporal sampling amplitudes, with projections conducted for 2004, 2006, 2008 and 2010, respectively. Efficiency of projection values was verified based on the Friedman and Kolmogorov-Smirnov test. The results indicate that the two tested models reliably estimate the number of trees of this forest fragment only for the temporal amplitude of 2 years.

Teores de carbono em espécies da floresta ombrófila mista e efeito do grupo ecológico

This study was conducted in Boa Ventura do Sao Roque, Parana State, Brazil, aiming to evaluate the carbon concentration in components of 12 arboreal species from the Araucaria Forest, as well as the performance of the 0.5 conversion factor and the influence of trees ecological groups in their carbon concentration. Carbon concentration averages were obtained from the tree components, and compared among them, among the species and the conversion factor, to assess the interspecific differences and the reliability of the conversion factor. To analyze the influence of ecological groups over the carbon concentration of the species, cluster analyzes were performed. It was not found significant difference among the carbon concentration in the components of the trees. However, comparing the 12 species, Luehea divaricata, Albizia polycephala and Cestrum sp. differed significantly, presenting lower carbon concentration. Comparison between carbon concentration average of the species and the 0.5 conversion factor indicated that the latter overestimates the carbon concentration in the trees at an average rate of 14.27%. No correlation was found between the ecological groups of the species and their carbon concentration, since groups were formed by species with distinct ecological traits.

MODELAGEM DE OCORRÊNCIA DE COORTES NA ESTRUTURA DIAMÉTRICA DA Araucaria angustifolia (Bertol.) Kuntze

Studies concerning the diameter structure are essential for understanding the development of native forests, provide growth and yield parameters sufficient to generate estimates that support sustainable management. However, the mathematical modeling of probability functions, such as density, becomes difficult to implement in multi-modal distributions, found in forest species and communities. The species Araucaria angustifolia (Bertol.) Kuntze, of social, environmental and economic features, presents multimodal distribution pattern forming units called demographic cohorts, which arise due to natural and anthropogenic agents that operate in niches. Therefore, taking inventory database of trees with a diameter at breast height equal to or greater than 9.5 cm (DBH≥9.5 cm), from the National Forest of Sao Francisco de Paula, RS, it was possible to test different probability density functions. The best fit to the data series consists of a truncated polynomial function of seventh degree, which besides maintaining fitted values ​​very close to those observed for total and diameter classes, maintained the multimodal distribution characteristic.

AGREGAÇÃO DE UM CAMBISSOLO HÚMICO EM POVOAMENTOS DE Pinus taeda L. COM DIFERENTES ROTAÇÕES

The study aims to verify whether the introduction of the specie Pinus taeda L. in soil under natural field alters the aggregation of Haplumbrept, at differents rotations. The study was conducted in the region of Campos de Cima da Serra, in the municipality of Cambara do Sul – RS state, Brazil. In order to achieve the goal above described, were selected two study areas, one in the first rotation (RT1) and another in the second rotation (RT2), with 13 years of old. For each stand, a combined area of natural field adjacent (control) was assessed. In each area, five trenches were opened and soil samples collected at depths from 0.0 to 0.05, 0.05 to 0.20 and 0.20 to 0.40 m to determine the percentage stable aggregates in each class (AGRI) and geometric mean diameter water stable aggregates (DMG). There was no change in the aggregate stability in the surface layer (0.0 to 0.05 m). However, the subsurface layers (0.05 to 0.20 and 0.20 to 0.40 m), just RT1 maintained stability of larger aggregates. Due to management adopted in RT2, such as burn and clear cut, there was a reduction in stability and increase in macro-aggregates smaller aggregates, whereas in the natural field stability in depth was maintained.

STRATEGIES FOR STEM MEASUREMENT SAMPLING: A STATISTICAL APPROACH OF MODELLING INDIVIDUAL TREE VOLUME

O objetivo deste trabalho foi avaliar diferentes criterios para amostragem de fustes para medicao e identificar o criterio mais adequado para a modelagem do volume de arvore individual. Os dados foram coletados em povoamentos de eucalipto com idade entre 58 e 65 meses. O modelo de Schumacher-Hall foi aplicado em cinco criterios de amostragem, com nove variacoes (45 no total): 1) numero de arvores por classe diametrica, sendo (a) numero fixo, (b) proporcional a distribuicao do diâmetro amostral, ou (c) proporcional ao desvio padrao da amostra; 2) tamanho da amplitude da classe diametrica, que variou de 1,0 a 5,0 cm. As equacoes geradas em cada criterio foram usadas para estimar o volume de fuste de arvores reservadas para validacao. Isso permitiu calcular erros padroes da estimativa para esse conjunto de dados. Alem disso, os residuos das estimativas de volume foram examinados por meio de testes estatisticos para vies, autocorrelacao e heteroscedasticidade. Os resultados mostraram melhores performances de equacoes de volume usando menores amplitudes. Nao houve uma clara tendencia em aumentar/reduzir a autocorrelacao e/ou heteroscedasticidade dos residuos. Aquelas amostragens com proporcao a frequencia da classe diametrica apresentaram as melhores performances, inclusive usando apenas 36 arvores. Aquelas cuja escolha de arvores foi proporcional ao desvio padrao tiveram os piores resultados. Como conclusao, a selecao proporcional a frequencia da classe diametrica, sob condicao de amostrar pelo menos duas arvores por classe, fornece modelos estatisticamente superiores aos demais quanto aos criterios sugeridos no estudo.