This study of 23 pollen samples allows recognition of a sequence of ecosystem changes occurring in central New Mexico between A.D. 1280 and 1400 and also in the 1650 - 1750 period. It also discusses the effects of such changes on aboriginal maize agriculture. Draft of the report included in Archaeological Excavations at Pueblo del Encierro.

Surface samples and stratigraphic sample series from 3 archaeological occupation sites and 2 samples from a burial site were examined for pollen in hopes of establishing a pollen sequence and paleoenvironmental interpretations. Both objectives achieved. Discussions of absolute dates of Woodland and Upper Republican contexts in this area and cultural ecology are included.