In this study, autoecological traits of three Amazonian terra-firme tree species grown in enrichment plantation lines were evaluated. The microclimatological parameters also were assessed in these lines. The study site is located in Novo Aripuanã, Amazonas State, Brazil (5(0)18'S, 60(0)04'W). Light condition in the three width lines (3, 5 and 7m) were assessed using hemispherical photographs and PAR sensor focusing radiation parameters. Although lines of 5 and 7m widths can be classified as large canopy opening (19,77-20,78%), lines of 3m represented major PAR variation. For soil chemical analysis, a significant reduction of K ans Ca was observed. Three tree species seedlings, Astronium lecointei Ducke, Cordia goeldiana Huber and Scleronema micranthum Ducke were set in the enrichment plantation lines. The relative growth rate (stem diameter+height) and chlorophyll contents were monitored in these plants. All species were subjected to high direct and diffuse radiation, low levels of nutrients and water stress. Astronium lecointei Ducke showed high drought resistance. Scleronema micranthum in the rainy season also benefited in the wider enrichment lines, showing positive responses to direct radiation. These two species showed features of intermediate to shade tolerant species (broad niche) when growth patterns were compared. On the other hand, C.goeldiana showed greater growth fluctuation than others (VC: Cordia goeldiana: 113> Astronium lecointei: 60,6> Scleronema micranthum: 59,7). Lines with five meters widths of primary terra-firme forests should be sufficient to establish shade tolerant and intermediate species.
Radiation; hemispherical photograph; tree-seedling; enrichment line; Amazônia