Micrometeorological parameters were measured in a closed forest (CF) and at a tree-fall gap (LG) near Novo Aripuanã, AM, along the Madeira River in dry season (August to September 2003) and rainy season (March 2004), and were compared to the number of species per family and the number of seedlings obtained from forest inventory. The daily averages of net radiation (W/m2) between CF and LG were 9.5:168.0 during dry season and 3.6:125.9 during rainy season, and these averages were influenced by the difference in shortwave radiation between the sites (CF<LG). Likewise, the diurnal range of soil heat flux, soil temperature, air temperature, and saturation deficit were all CF<LG. These site differences were explained from the sky-view factor (CF: 14.8±3.9%, LG: 43.6±6.0%). Frequently-occurring tree-falls and recoveries resulted in increases in the numbers of colonizer species, such as Burseraseae, Cecropiaceae, Meliaceae, Myristicaceae, Simaroubaceae, Violaceae, and Sterculiaceae. From the comparison of the number of seedlings at mini-plots, some genera, which have established themselves in response to improvements in environments at gaps, were found, such as Pourouma, Parkia, Tachigalia, and Orbignya, meanwhile genera peculiar to closed forests (Protium, Chrysophyllum, Micropholis) were also found.
micrometeorological environments; closed forest; tree-fall gap; biodiversity