Significance The extent to which pre-Columbian societies in Amazonia occupied and significantly altered the tierra firme (nonflooded, nonriverine) forest environment is an enduring question and the subject of a current debate. Our research addresses these issues in tierra firme forests of northeastern Peru. We present phytolith and charcoal data indicating the forests were not cleared, farmed, or otherwise significantly altered in prehistory. Frequencies of hyperdominant palm species did not increase through time, indicating prehistoric human exploitation contributed little to the species’ disproportionate abundance in the modern flora. Our data indicate that forest resurgence and fire decrease upon the tragic consequences of European contact were not so widespread as to have been principal contributors to the onset of the “Little Ice Age.”