By Misty Edgecomb, OSU release - CORVALLIS, Ore. – It sounds like the setup for a holiday romantic comedy – Priya Rajarapu works as a Christmas tree expert for Oregon State University’s Extension Service, helping Oregon’s 300-plus Christmas tree growers produce a healthy crop each holiday season so that the state can export millions of perfect trees across the world.  But this job is more science than sentiment. In her Extension role and as an assistant professor in the College of Forestry, Rajarapu, who earned her doctorate in entomology, is studying how to keep Oregon’s holiday industry thriving as the climate changes.  “Oregon is a perfect place to grow evergreens because of the climate,” she said. “Our mild summers and wet winters are ideal for native species like noble and Douglas-fir that are traditionally among the most popular Christmas trees in the Western United States.  “If you’re sick you call a doctor. If you’re a Christmas tree grower who has a sick tree, you call me.”  As temperatures rise and weather patterns shift, the cost to maintain a healthy crop of Christmas trees is rising. And once-rare extreme climate events, like the 2020 fires and the 2021 heat dome in Oregon can have decades-long impacts on forests that affect the holiday tree industry.  “Our goal is to help the current and future growers sustain production of Christmas trees on their land,” Rajarapu said. Long a sustainable industry, with at least one tree going into the ground for every one cut, Christmas trees are an important agricultural crop for Oregon.  Oregon sold 3.17 million trees in 2023 (the most recent year for which federal statistics are available) – making it the top Christmas tree grower in the United States and contributing $118 million to Oregon’s economy. Industry associations estimate that Christmas tree prices should remain stable this year, averaging about $12 to $15 per foot, and don’t anticipate that tariffs and trade policies will have a significant impact on the tree industry.  To support growers, Rajarapu and her colleagues are working at North Willamette Research and Extension Center in Aurora to develop new resilience strategies. For example, an ongoing study is looking at different mulch alternatives to understand whether any of these mulches boost seedling survival during their first year.  Native noble fir makes up just over half of Oregon’s Christmas tree sales, but in recent years, OSU Extension experts have also been studying the genetics of introduced species from Eurasia that are potentially more resilient to climate change. Before his retirement, Rajarapu’s predecessor Chal Landgren personally carried seeds back from Georgia, establishing the new species at the three-acre field site that she now oversees.  These new-to-Oregon species can hold their needles longer after they’re cut and displayed. For example, Nordemann and Turkish fir, both native to Georgia, now make up a small but growing percentage of Oregon’s crop.  “They’re drought-and pest-tolerant,” Rajarapu said. “That reduces the need for inputs such as chemical insecticides.”  More than half of Oregon’s Christmas trees are sold in California each year, with other Western states, Mexico, Canada, Hong Kong, Japan, Panama, Singapore and Maldives among Oregon growers’ top markets, according to the Oregon Department of Agriculture.  “With consistent water, these new species can hold their needles for four-to-six weeks indoors,” Rajarapu said. Additives like sugar or alcohol that claim to lengthen a tree’s life indoors aren’t backed by scientific evidence, she explained, but lots of water, especially in the first few days, is key to a tree that lasts the season.  “When you buy a real tree, you’re supporting a local business,” said Rajarapu, who is planning to display a noble fir at her home this year. “And it just smells and feels like Christmas.”