Drier summers and a decline in average snowpack over the past 40 years have severely hampered the establishment of two foundational tree species in subalpine regions of Colorado’s Front Range, suggesting that climate warming is already taking a toll on forest health in some areas of the southern Rocky Mountains.
Drier summers and a decline in average snowpack over the past 40 years have severely hampered the establishment of two foundational tree species in subalpine regions of Colorado’s Front Range, suggesting that climate warming is already taking a toll on forest health in some areas of the southern Rocky Mountains.
The findings, which were published today in the journal Ecology, show that spruce and fir tree establishment was limited to a handful of years with above average snowpack and cooler, wetter summer conditions—all of which have grown scarcer in recent decades. The study is believed to be the first to reconstruct establishment frequency on an annual basis for the two conifer species.
“Since 1975, there have been fewer favorable years for seedling establishment,” said Robert Andrus, lead author of the study and a graduate researcher in CU Boulder’s Department of Geography. “Our study indicates that moisture availability is the key driver for these events in Colorado’s high elevation forests.”
Rising temperatures have increased the rate of tree mortality across the American west, including subalpine forests in the Colorado Front Range, making it imperative for spruces and firs to establish successfully and regularly in order to replace fallen cohorts. In subalpine coniferous forests, seedling establishment occurs when large quantities of available seeds coincide with favorable climate conditions.
Read more at University of Colorado at Boulder
Photo Credit: CrystalDawn via Pixabay
