WSU’s ‘Dr. Christmas Tree’ working on massive project to enhance firs

21 Dec 2025, 09:12 by Nick Gibson · The Seattle Times

“Dr. Christmas Tree” is a weighty title to bestow on someone.

After 48 years of diving into the nitty-gritty of the perfect holiday foliage, Gary Chastagner has earned the moniker.

A professor emeritus at Washington State University, Chastagner is considered one of the world’s foremost experts on tree and ornamental flower bulb pathologies. In 2018, he received a lifetime achievement award from the National Christmas Tree Association for his towering body of work that’s helped reshape the holiday symbol.

Chastagner said he’s had a rewarding career and continues to contribute to research despite retiring last year.

“To hear the growers talk about how it has had such a positive effect on their ability to produce high quality trees, reduce pesticide applications and think of things and give them ideas on alternative approaches they could use to help them sustain the production of their trees,” Chastagner said, “I mean, you can’t ask for anything more.”

Lately, Chastagner is lending his expertise to one of the largest and most extensive federally funded Christmas tree projects to date. Researchers across nine institutions in multiple countries, including WSU and Oregon State University, are in the midst of a multiyear collaboration dubbed “A GIFT SEED,” which stands for Accelerated Genetic Improvement of Fir Through Sequencing, Economics, Extension and Diagnostics.

The nearly $7.5 million project funded by a USDA National Institute of Food and Agriculture grant has experts across a variety of disciplines exploring all things firs, including how they can better withstand pests, disease and a changing climate, the characteristics that make them appealing to consumers and how tree growers could break into new markets.

Christmas tree farms are big business. More than 14.5 million trees were cut in 2022 from the roughly 16,000 farms in the United States, generating more than $553 million in proceeds, which is the most recent data available from the USDA. Oregon and North Carolina led the pack, with their totals comprising more than half of the entire country’s production. Washington came in fourth, producing around a million commercial Christmas trees.

The majority, around 75%, of the trees cut and sold each year are of the fir variety, said project lead Justin Whitehill, an associate professor and director of the Christmas Tree Genetics Program at North Carolina State University. If Douglas firs are included, which are not technically true firs, the number of real Christmas trees that are firs of some sort jumps to 93%, he said, leaving rival pines in a very distant second and spruce trees even further behind.

“True firs are really the most popular species, and the reason they’re not sold and grown everywhere is because the trees just don’t grow everywhere,” Whitehill said. “That’s part of this project too, is to sort of help identify trees that maybe could be grown in other parts of the country.”

He said firs look better and smell better, lending to their status as the best and popular Christmas trees.

Chastagner has had a hand in a large portion of that prior research, and by extension advancements in the Christmas tree industry. He was hired at WSU in 1978 to work on bulb crops like flowers and turf grass at a time when the state’s Douglas fir growers were contending with a pesky disease known as Swiss needle cast caused by a fungal pathogen. The state Legislature wanted solutions for those farmers and turned WSU researchers.

That initial assignment turned into a lifelong career on tree farms, lots and in laboratories, where Chastagner’s research has led to Christmas foliage that is, in part, fuller, lasts longer, casts less needles and is more resistant to disease and pests. He said it’s been an incredibly rewarding experience to watch research on the industry evolve and develop over the years, and to watch others build on those early findings.

“One simple little problem, Swiss needle cast, has resulted in all of these other things happening,” Chatagner said.

Nowadays, noble firs are top of the list for Northwest consumers. Trees have regional popularity, said Whitehill, pointing to the widespread popularity of the Fraser fir in and around North Carolina. Consumer preferences, and the underlying science contributing to those characteristics shoppers are looking for, are some of the many aspects of firs that Whitehill, Chastagner and associates are exploring.

Earlier this year, volunteers in Pullman lent their noses, and opinions, to project collaborator Carolyn Ross, a food sciences professor and director of the WSU Sensory Science Center. The study was half of a joint exploration, with another panel conducted at the University of Florida, of the role aroma plays in choosing the perfect December living room fixture.

“We wanted to sort of dig into the chemistry and the biology of that and compare some of these different popular species on both the East and West Coast, and get a better idea of what are the underlying genetics,” Whitehill said. “And as we’re working on breeding trees, is there anything we can do to maintain or improve or modify, play around with, the chemistry of the trees?”

Mirroring collaborators at the University of Florida, Ross had volunteers evaluate bough segments from five varieties of fir trees, the Fraser, noble, Nordmann’s, Trojan and concolor. Panelists were asked how much they liked the aroma, appearance, the intensity of the scent, and what specific aromas their noses were picking up — like notes of citrus.

Fraser firs were found to be most popular by scent, while noble firs came in last, according to initial findings.

“If it was on the East Coast or West Coast, typically, folks tended to prefer the aroma of the Fraser fir, which, of course, is great news for North Carolina,” Whitehill said. “Washington state, maybe not as excited about that finding, given the importance of noble fir.”

Whitehill and Chastagner said they look forward to seeing the project continue, and incorporating the aroma findings into explorations of the underlying genetics, natural defenses against insects, grazing deer and disease and potential industries to break into for tree growers.

“It’s exciting, I get to sort of incorporate my background, which includes genetics and pathology, with aroma chemistry, biology, genomic work, all of that, to really tackle the major issues facing the industry,” Whitehill said.

The multiyear project is intended to benefit consumers as much as growers and understanding of the natural world, making it a real “win-win,” Chastagner said.

These little trees, we ask them to do a lot,” Ross added. “You know, retain their needles, stay looking nice, be a nice shape, continually pump out aromas for however long you have it in your house. And there’s a lot of nostalgia associated and preferences. So there’s a lot tied in with our understanding of Christmas trees.”