Poulos, Students Collaborate on 2 Publications

Helen Poulos, adjunct assistant professor of environmental studies, is the coauthor of two published papers in February.

“Response of Arizona cypress (Hesperocyparis arizonica) to the Horseshoe Two Megafire in a south-eastern Arizona Sky Island mountain range,” is published in the February issue of International Journal of Wildland Fire (Issue 28, pages 62-69). It is coauthored by Andrew Barton, professor of biology at the University of Maine at Farmington.

This study documents the effects of the 2011 Horseshoe Two Fire in the Chiricahua Mountains of southeastern Arizona on Arizona Cypress. Two Wesleyan students, Hunter Vannier ’20 and Michael Freiburger ’21 assisted with the fieldwork in 2018 as part of their College of the Environment summer fellowships.

The group documented the effects of a fire-sensitive tree species that survives wildfire through fire-induced seed release (serotiny). On sites subject to severe fire, most mature cypresses were killed, the canopy opened, and seedlings established abundantly. Their results firmly establish Arizona cypress as a fire-sensitive but fire-embracing species that depends on stand-replacing fire (the loss of overstory trees) for regeneration.

“A drier future with more frequent wildfires could pose serious threats to all New World cypresses if these species do not have enough time between fire events to reach sexual maturity,” Poulos explained.

The second paper, titled “Invasive species and carbon flux: the case of invasive beavers (Castor canadensis) in riparian Nothofagus forests of Tierra del Fuego, Chile” was published in the February issue of Climatic Change. It is coauthored by biology major Chloe Papier ’17 and Alejandro Kusch of the Wildlife Conservation Society in Punta Arenas, Chile.

For this study, Papier completed a month of fieldwork in Patagonia on a College of the Environment winter fellowship.

The researchers documented the effects of invasive North American beavers (Castor canadensis) on carbon sequestration of riparian Nothofagus forests in Tierra del Fuego, Chile. Their results suggest that beaver invasion can result in major differences between aboveground carbon in invaded versus un-invaded forest stands.

Gary Yohe, professor of economics; the Huffington Foundation Professor of Economics and Environmental Studies; and professor, environmental studies; serves as the coeditor in chief of the journal.