José Imaña-Encinas

Contribuição da vegetação rasteira na evapotranspiração total em diferentes ecossistemas do bioma cerrado, Distrito Federal.

The objectives this study were to: (a) quantify the seasonality evapotranspiration of understory vegetation (ET rasteira), (b) quantify the influence of ET rasteira on total evapotranspiration (total ET) and (c) verify the relation between ET rasteira and Leaf Area Index of the understory vegetation (LAI rasteira), open canopy and soil water potential, in four distinct landscapes: Cerrado stricu sensu , Gallery Forest, Brachiaria pasture and Eucalyptus reforestation, situated in the APA Gama-Cabeca de Veado, Districto Federal. An open-top chambers for understory vegetation, non-dispersive infrared gas analyzer, plant canopy and leaf area index analyzer; and soil psychrometers were used to collect data. The ET rasteira contributed significantly to total ET, mainly during rainy season, approximately 60 % of the annual mean of total ET, in Cerrado strictu sensu and Gallery Forest areas. Significant and directly proportional relationships between ET rasteira and the understory LAI, open canopy and soil water potential were observed, this influenced by rain seasonality.

Influência do vento no volume de toras e no fator de forma de Pinus caribaea var. hondurensis

The objectives of this research were to quantify wind speed and to observe its influence on the form factor and on the volume of logs along the stem, in boundary and within Pinus caribaea var. hondurensis plantation situated in the county of Jaborandi City (BA). The wind speed data was measured by anemometers; the log volume by xilometer, and the form factor was got by division of log volumes measured with xilometer by adjust volume of trunk section by cylinder. Significant differences between the samples studied in boundary and within of plantation, were evidenced by a statistical non parametric test. The sigmoidal and inversely proportional relationship was observed between wind speed and the variables volume and form factor of trunk section of P. caribaea var. hondurensis, in other words, when the higher value of the wind speed is registered, lower values of form factor and the log volume were measured.