Drought, Bark Beetles Led to Pinyon and Juniper Mortality

Consecutive years of drought likely led to bark beetle attack of pinyon pine and juniper forests and the mortality of millions of these trees in the Southwest since the late 1990s, according to a recent study in Ecohydrology. Most of the mortality occurred between 2003 and 2004 and in some places up to 90 percent of the two tree species have died. Science Daily explains that the widespread dieback of these dominant tree species is of great concern because, alive, they nourish other plant and animal species and prevent serious soil erosion. Without these trees to stabilize the soil, wind becomes an effective erosion agent. The associated dust often lands on snowpacks where its darker color causes them to melt more rapidly, a phenomenon that could ultimately result in reduced Colorado River (and others) streamflow.