October 4, 2017
Remote sensing technology has detected what could be a win for both spotted owls and forestry management, according to a study led by the University of California, Davis, the USDA Forest Service Pacific Southwest Research Station and the University of Washington.
For 25 years, many forests in the western United States have been managed to protect habitat for endangered and threatened spotted owls. A central tenet of that management has been to promote and retain more than 70 percent of the forest canopy cover. However, dense levels of canopy cover leave forests prone to wildfires and can lead to large tree mortality during droughts.
In the study, published in the journal Forest Ecology and Management, scientists found that cover in tall trees is the key habitat requirement for spotted owl—not total canopy cover. It indicated that spotted owls largely avoid cover created by stands of shorter trees.
"This could fundamentally resolve the management problem because it would allow for reducing small tree density, through fire and thinning," said lead author Malcolm North, a research forest ecologist with UC Davis' John Muir Institute of the Environment and the USDA Pacific Southwest Research Station. "We've been losing the large trees, particularly in these extreme wildfire and high drought-mortality events. This is a way to protect more large tree habitat, which is what the owls want, in a way that makes the forest more resilient to these increasing stressors that are becoming more intense with climate change."