Drought is endemic to the American West along with heatwaves and intense wildfires. But scientists are only beginning to understand how the effects of multiple droughts can compound to affect forests differently than a single drought alone. UC Santa Barbara forest ecologist Anna Trugman — along with her colleagues at the University of Utah, Stanford University and the U.S. Forest Service — investigated the effects of repeated, extreme droughts on various types of forests across the globe. …Two clear tends emerged. “We found that generally trees seem to become more vulnerable to stress after multiple droughts, especially conifers,” Anderegg said. The second finding comes down to basic physiology. Conifers and their kin have different vascular systems than broadleaf trees, or “angiosperms.” As a result, they may sustain more damage in an initial drought and be at a disadvantage compared to angiosperms during subsequent periods of drought stress.