Insights from recent fires into juniper savanna dynamics at Wupatki National Monument, Arizona, USA

Abstract

We tested the hypothesis that recurrent fires may limit juniper expansion into southwestern semiarid grasslands and savannas. Seven large fires at Wupatki National Monument, Arizona, burned 38% of the grasslands and dynamic savannas between 1995 and 2017. Mortality of one-seed junipers (Juniperus monosperma) was >50% among smaller trees (<2 m tall), <40% among larger trees (>2 m tall), and 0% in trees >4 m tall. Herbaceous vegetation recovered within 2 to 3 years postfire. This suggests that fires may have limited juniper expansion historically and that fire may be an option for controlling juniper expansion and restoring grassland/savanna ecosystems today.