Growing better Christmas trees

After a week of visiting various locations in Oregon and Washington, the ninth International Christmas Tree Research and Extension Conference capped off its recent annual meeting with a tour of the 18 acres of Christmas tree research plots at the WSU Puyallup Research and Extension Center.

“This is a group that involves the leading Christmas tree researchers from around the world,” said WSU plant pathologist and internationally known Christmas tree researcher Gary Chastagner, who hosted the tour. “Getting together allows us to learn about what each other is doing, and to develop cooperative projects where we can work on common issues that are affecting the Christmas tree industry.”

Gary Chastagner explains needle retention trials.
Gary Chastagner explains needle retention trials.

According to Chastagner, Christmas trees are a significant industry in the Pacific Northwest.

“Washington and Oregon provide more than 10 million Christmas trees annually, or about 35 to 40 percent of the trees grown in the United States,” he said. “We are the country’s largest production region, and it’s a multi-million dollar industry.”

The tour focused on two major issues: Identifying and evaluating species and genetic stock for high moisture and needle retention characteristics, and evaluating the susceptibility of true firs to Phytophthora root rot.

The group toured four trial plots where Chastagner’s team is evaluating Phytophthora root rot susceptibility in 14 true fir varieties. The disease is a common problem in the production of the popular Noble fir, particularly in areas with high soil moisture like the maritime Pacific Northwest.

Chastagner also demonstrated the approaches he and his team have developed for evaluating needle retention. With more than 90 percent of Northwest-grown Christmas trees being exported out of the region, it’s critical that trees retain moisture and needles through the shipping process, and ultimately in the homes of consumers.

Phytophthora root rot results.
Phytophthora root rot results.

The Danish Connection

Danish researcher Ulrik Neilsen with the University of Copenhagen said that’s a crucial issue for his program, and one of the reasons he was eager to see Chastagner’s current research.

“Moisture content – being sure that the needles stick to the trees – that’s a very serious issue,” said Neilsen. “We started working with Washington State University and Gary Chastagner about ten years ago, looking into post-harvest quality of trees. That’s one of the things that you are very good at in Washington, being one of the pioneers in the area of evaluating trees.”

A Learning Opportunity

The benefit of the group’s annual gatherings, and especially the farm tours, goes beyond scientific collaboration and comparing research results, said Chastagner.

“We learn things every place we go, from the growers all the way up to our fellow scientists,” said Chastagner. “Sometimes it’s the grower who is doing a certain thing, but he may not understand why it’s working. When you’ve been in the business of research you understand some of the issues, and you’re constantly looking for clues to how to solve problems.”