Growth and survival of Brazil nuts (Bertholletia excelsa Bonpl.), in different environmental conditions in region River Trombetas, Oriximiná, Pará, Brazil

This study examines the growth and survival of Brazil nut tree (Bertholletia excelsa, Lecythidaceae) in different environmentalconditions within experimental plantations in the Trombetas River valley. One hundred and forty four saplings were plantedin a random block design, with three natural light treatments: manioc field (100% canopy removal), young secondary forest(20-80% canopy cover) and the understory of a Brazil nut plantation (< 10% canopy opening). Every two months for aperiod of two years plant height and stem diameter were measured, and mortality and regrowth were noted. There weresignificant differences in the performance of Brazil nut saplings between treatments, with the most marked differences beingat the highest level of luminosity (manioc field). The open field saplings grew in height 13 times more than those planted insecondary forest, and nearly 30 times more those in the understory of the plantation area. The open field saplings exhibiteda growth in diameter 4.4 times greater than saplings planted in secondary forest and 7.7 times greater than saplings planted inthe understory. Regardless of the light treatment, the Brazil nut saplings had high survival rate and exhibited strong regrowthfollowing stem damage. Overall we report that Brazil nut saplings perform better in full daylight conditions such as abandonedcrop fields and forest gap. In enrichment or reforestation plantings, vegetation around Brazil nut plants should be cleanedfrequently to avoid over-shading the crown and to guarantee high growth rates.