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Dendrochronology of Utah juniper

Date: August 01, 2016

Dendrochronologists have long thought that Utah juniper could not be dated using conventional tree-ring approaches. Researchers recently detailed crossdating of four Utah juniper sites in northern Utah to demonstrate it is possible


Cross section of a dead Utah juniper.
Cross section of a dead Utah juniper.
Annual precision of tree-ring data is often sought for detailed analyses. Important, widespread species such as ponderosa pine and Douglas-fir are often used for tree-ring science. However, there are other low elevation species, oftentimes termed woodland trees that could also be useful, including Utah juniper.

Researchers recently conducted dendrochronological investigations of Utah juniper tree rings from four sites in northern Utah. They demonstrated that, contrary to the general opinion among many dendrochronologists, Utah juniper exhibits excellent crossdating that is reflective of its sensitivity to climate — a desirable characteristic for dendroclimate reconstruction. Across all four sites the dominant signal for annual ring-width increment occurred during the growing season and was positive for precipitation and negative for temperature. This corroborates ecophysiological studies that highlight Utah juniper’s ability to survive at very low soil water. This behavior differs from co-occurring pines that survive drought by shutting down growth.

Researchers determined that the annual radial increment of Utah juniper rings is particularly responsive to soil moisture availability, and is in fact a useful proxy for hydroclimatic variables such as precipitation, drought, and streamflow. Its geographic distribution spans a large swath of the Interior West, including areas where other more commonly sought-after species for dendrochronology do not occur, and ought to be considered crucial for complementing the rich network of tree-ring chronologies in the western United States.

Key Findings

  • Utah juniper can be crossdated and its width is reflective of growing season moisture availability
  • Utah juniper occurs at lower elevations than other common species, so the ability to crossdate this species can expand the network of tree-ring chronologist in the western U.S.

Featured Publications

DeRose, R. Justin ; Bekker, Matthew F. ; Kjelgren, Roger ; Buckley, Brendan M. ; Speer, James H. ; Allen, Eric B. , 2016

Principal Investigators: 
Principal Investigators - External: 
Matthew Bekker - Brigham Young University
Roger Kjelgren - Utah State University
Brendan Buckley - Columbia University
James Speer - Indiana State University
Eric Allen - Utah State University