Category Archives: Silviculture

Researching ‘birds and bees’ for conifer trees

Douglas fir cone "flowers," Technically, Douglas-fir are not flowering plants, but its young female cones, shown here, are often referred to as “ flowers.” Genetic variation yields “ flowers” of various hues; it also influences the timing of flowering in different populations. Knowing when Douglas-fir are going to flower helps seed orchards have staff ready for the labor-intensive pollination process that yields high-quality Douglas-fir seeds. USDA Forest Service photo by Janet Prevey.

“Timing is everything, especially when it comes to tree sex.”

In the latest Science Findings, researchers from the USDA Forest Service – Pacific Northwest Research Station delve into nature versus nurture in conifer reproduction.

To successfully reproduce, conifers, or cone-bearing trees, must have impeccable timing to open their female cones just as pollen is being released from from the male cones of nearby trees.

This timing is a response to temperature and other environmental cues. It is to the tree’s advantage to flower when risk of damaging frost is low, but early enough in the spring to take full advantage of the growing season.

Since Douglas-fir is ecologically important and the cornerstone of Pacific Northwest’s timber industry, seed orchard managers carefully breed different populations of the species to produce seedlings that will thrive in particular areas in need of replanting.

Understanding the environmental cues that influence the timing of flowering is important for predicting how reproduction and survival of trees will change in the future.

To address this need, a team of researchers with the USDA Forest Service Pacific Northwest Research Station developed a model that predicts, within an average of 5 days, when Douglas-fir will flower – which seed orchard managers are already using to plan and schedule time-sensitive tasks related to flowering in the orchards.

Read more in Science Findings #216, available at https://www.fs.usda.gov/treesearch/pubs/58039 (click “view PDF”), or navigate directly to the PDF publication at https://www.fs.fed.us/pnw/sciencef/scifi216.pdf.

Past editions of Science Findings are available here: https://www.fs.usda.gov/treesearch/

To subscribe to Science Findings and other publications from the Pacific Northwest Research Station, click here.


Source information: Josh McDaniel is a science writer based in Colorado. Research by Janet S. Prevey, research ecologist, Connie Harrington, research forester and Brad St. Clair, research geneticist at the Pacific Northwest Research Station. Science Findings is a publication of the USDA Forest Service – Pacific Northwest Research Station.