ECOSTRESS imagery leads to groundbreaking discovery in post-fire plant recovery

ECOSTRESS imagery is at the forefront of a groundbreaking identification of key mechanisms during post-fire plant recovery study leading to a better understanding of shifting landscapes and the future of wildland fire management in the Western Region. 

For centuries and perhaps millennia, the historical fire regimes of the west have been dominated by frequent, low-severity wildfires through the late 19th century when fires virtually disappeared from the landscape due to grazing and fire suppression. Over a century of mounting fuel loadings, coupled with increasing aridity in recent decades has led to increases in fire size and severity across the western US. This has triggered a transition in many sites from pine forest to post-fire shrublands

For the past two years, Helen Poulos, assistant professor of environmental studies at Wesleyan University, has led a team of researchers deep into the rugged terrain of the Chiricahua Mountains in southeastern Arizona.  The study's goal is to better understand the effects of these high-severity wildfires on the ecology of western landscapes, most notably, the fire-triggered shift from pine-dominated forests to oak shrublands. 

Due to the new technology of ECOSTRESS, the team is the first in history to identify the specific plant mechanisms activated diurnally and seasonally, not just overarching patterns, in post-fire plant recovery.  In her study, Poulos and her team found that post-fire shrublands maintain high evapotranspiration (ET) throughout the morning and midday, while other vegetation types shut down ET by 10 a.m.  The discovery of high ET in post-fire plant recovery is contrary to former post-fire research that suggested that ET was depressed due to a reduction in transpirational surface area, i.e., no vegetation cover.  For oak shrublands specifically, the higher the severity of the fire, the higher the ET. 

This shift to oak shrublands is of grave concern in terms of water availability to plants and downstream end users. High ET involves cycling greater amounts of water from the soil into the atmosphere, lowering the water table.  Poulos and her team have been an asset to park managers around the Chiricahua Mountains to help them better understand the future trajectory of these forests and prepare for shifting management practices to protect dense pine areas.