Traditional Knowledge, Use, and Management of Aphandra natalia(Arecaceae) in Amazonian Peru. Along the Pastaza and Urituyacu rivers in Peru, 100 informants in four villages knew 17 different uses of the piassaba fiber palm, Aphandra natalia (Balslev and Henderson) Barfod. Human consumption of fruits, extraction of fibers for trade, and harvesting leaves for thatch were the most frequently reported uses. Twenty uses were documented previously in the literature, and eight are reported here for the first time. Knowledge concerning the use of A. natalia among villagers varied significantly with ethnicity, village, and gender, but not with education or age; Amerindian informants knew more than non-Amerindian informants, and men knew more than women. Old and young informants knew about the same numbers of uses, and those who had little formal school training knew as many as those who had attended school for a longer time. Although 44% of our informants knew about fiber extraction, trade involving Aphandra fibers was not of great economic importance in our study area. Because fiber extraction has been documented as the most important use in all previous studies of A. natalia, it was surprising to find that people in one of the studied villages did not use A. natalia for that purpose at all. In contrast to previous observations, the extraction of fibers involved the destructive felling of the palms. We recommend implementing non-destructive extraction techniques so that local communities could exploit the fiber resource in a sustainable way. Non-destructive extraction methods involve cutting leaves from standing palms instead of felling the entire tree and leaving a few leaves on each extracted palm. However, given the limited economic incentive to the extractor, market mechanisms may be the greatest barrier to implementing sustainable extraction techniques.