Advancements in Christmas trees credited to WSU professor

Science: Gary Chastagner’s research identified Nordmann fir to be most resistant to root rot

of the HeraldDecember 4, 2013 

If a perfect Christmas tree exists, it’s more than likely Gary Chastagner will be the one to discover it.

For more than 30 years, the professor of plant pathology at Washington State University’s Puyallup Research and Extension Center has conducted research on conifers of various origins to help identify species with good needle retention and those that are the most resistant to disease.

“I’m interested in making sure we can improve the overall quality of trees to consumers,” Chastagner said.

In 1981, Chastagner began to apply his plant pathology background to the Christmas tree industry when he researched ways to manage Swiss needle cast, a fungus disease that attacks Douglas fir in Washington and Oregon. At the time, the loss of needles caused by the disease was resulting in harvest losses that were estimated to be $3.4 million. The disease reduced the quality of trees once they were displayed indoors.

From his research, Chastagner helped to develop a disease management program. The treatment cost about five cents per tree.

Today, Swiss needle cast is all but eliminated from Christmas tree farms in the Northwest.

Included in his 15 acres of trees at the WSU-Puyallup Research and Extension Center are plantings of Eurasian Nordmann and Turkish firs. Chastagner’s research has shown that these species of trees, which originate from the Caucasus Mountains east of the Black Sea and Turkey, are resistant to Phytophthora root rot. This is a soil borne disease that limits where consumer desirable species, such as Noble fir, can be grown.

Chastagner and graduate student Katie McKeever are collecting isolates of this pathogen from all of the major Christmas tree production regions in the U.S. to identify the mechanism associated with resistance to Phytophthora root rot.

“Growers can plant Nordmann and Turkish firs in lower elevation sites with heavier soils, and they don’t have some of the diseases and pest problems that occur on other trees,” Chastagner said. “These exotics are promising new species in the Northwest.”

Nordmann firs account for 10 percent of production in the Northwest.

In addition to helping growers produce healthy trees, Chastagner also leads the largest research program relating to post-harvest care and handling of Christmas trees in the U.S.

Chastagner has performed shipping trials to a number of states and found that very little moisture loss occurs during shipment. His research also has been used to help Christmas retailers in warmer climates, such as Arizona, with the best practices to keep trees moist and fresh for a longer period of time. As a result, tree lot retailers now have timed misters that water trees on display regularly, Chastagner said.

“By maintaining high moisture content in cut trees, you reduce needle loss and improve the quality of trees available to consumers,” he said. “In the Pacific Northwest, growers are blessed that they can cut and store trees under our cool, moist conditions with very little moisture loss.”

From the Nordmann and Turkish fir trees, and the others from various origins, Chastagner and his team perform detached-branch tests in a controlled post-harvest lab on the extension center grounds. Each branch is given a number to identify the tree source. Branches are placed in the post-harvest lab, where the temperature is set at 65 to 68 degrees with humidity at 45 percent.

“We are looking for a slow drying of the branches that creates ideal conditions for the physiological process associated with the loss of the needles to occur,” Chastagner said. “After 10 days, we rate the branches and can tell which trees have genetically superior needle retention characteristics.”

Chastagner said needle trials start in late September and continue through December.

Through his needle retention research, Chastagner strives to identify species of trees that grow well and are resistant to needle loss. Growers have established a number of seed orchards using this material that will enable the industry to provide consumers with superior trees in the future.

Throughout his years of research, Chastagner said he’s benefited from collaborative partnerships with growers and colleagues at other institutions.

“In this day and age, it’s all about collaboration and relationships that enable us to find solutions to the complex disease and quality issues growers are facing,” Chastagner said. “Growers appreciate when someone comes out and helps them with their problems.”

Reporter Andrew Fickes can be reached at 253-552-7001 or by email at Follow him on Twitter, @herald_andrew.

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