Disturbing Developments: An Archaeobotanical Perspective on Pinyon-Juniper Woodland Fire Ecology, Economic Resource Production, and Ecosystem History

Abstract

It has long been thought that the only means by which the American Southwest's extensive pinyon-juniper woodlands, with their inherently low primary productivity, could have supported indigenous populations during prehispanic times was with the transformative consequences associated with the widespread cultivation of low-moisture-intolerant domesticated plants, principally maize (Zea mays L.). In this paper we present an alternative to this orthodox view which posits that anthropogenic fire was a vegetation-community management technology that was used to create disturbance patches and to propagate abundant, edible seed-rich ruderals in them. This perspective allows us, as well, to introduce and illustrate the interpretive possibilities of a conceptual scheme that focuses on three resource production types—cultivated wild plants, gathered wild plants, and domesticated plants—with multi-contextual macrobotanical data from a partially burned and rapidly abandoned multi-room settlement (occupied between AD 1070–1080) located south of the Grand Canyon in northern Arizona. By integrating these data with previous archaeobotanical, pollen, and sedimentary micro-charcoal studies, we propose that the systematic cultivation of wild plants in pyrogenic resource patches was a sustainable practice that enhanced food-supply security by insulating populations from the effects of short-term environmental variability and long-term climate change that challenge maize farmers. Importantly, these investigations indicate that low-intensity burning did not involve widespread deforestation, as some models of Holocene climate change suggest, and that prehistoric depopulation and modern fire suppression have altered fundamentally the composition and economic potential of contemporary pinyon-juniper ecosystems.