WSU research tucked inside traveling Capitol Christmas Tree


By Betsy Fradd, WSU Extension

PUYALLUP, Wash. – Tucked within the massive Capitol Christmas Tree headed for Washington, D.C. are three tiny sensors most people will never see. They will collect information on how well the tree holds moisture during its 25-day journey from Washington state.

Tree-placing-hobo-550Researcher Katie McKeever placed the data devices deep inside the canopy of the 88-foot-tall Engelmann spruce last weekend as it was loaded onto a flatbed trailer on the Colville National Forest in Pend Oreille County.

“These HOBO data loggers automatically measure temperature every 15 minutes, providing statistics about the ambient environment inside the tree canopy,” said McKeever, a graduate student in plant pathology at Washington State University Puyallup. “Information will be collected to observe any changes in the moisture content of the tree during shipment.”

Tree-hobos-closeupData from the Paul Bunyan-size tree will be compared with the results of work on traditional-size trees at WSU Puyallup where Gary Chastagner leads the plant pathology research program ( on post-harvest moisture and needle retention of Christmas trees. U.S. Department of Agriculture Forest Service technicians responsible for the Capitol tree will send daily samples of small twigs to WSU Puyallup where they will be weighed and oven-dried to calculate moisture content.

The last time the Capitol Christmas Tree came from Washington state was in 2006; it was harvested from the Olympic National Forest.

A water reservoir wraps the base of the tree trunk.

Chastagner tracked changes in the moisture content of that tree and will use that information and the new data to better understand the post-harvest moisture status of large-scale forest trees. The information will help validate post-harvest care and shipping recommendations provided to producers to improve the quality of trees available to consumers.

The Capitol Christmas Tree will make several stops in Washington state for community celebrations and will travel throughout the country before arriving in Washington, D.C. by Thanksgiving. Follow it at



Gary Chastagner, WSU Puyallup,, 253-445-4528

Betsy Fradd, WSU Puyallup communications,, 253-445-4543, cell 253-241-5043