One of the most popular tree species used to deck the halls is in danger of going extinct in the wild. Although it is grown extensively in cultivation for use as a Christmas tree, Fraser fir (Abies fraseri) faces numerous threats to its existence.
The Missouri Botanical Garden is fighting for the future of this species by collecting and banking seeds from wild populations of Fraser fir. You can read more about the plight of the Fraser fir, and our field work, in this post from 2019.
Now, two years after the wild-collected Christmas tree seeds made their way from the Appalachian Mountains to St. Louis, our researchers are learning more about the challenges ahead when it comes to conserving this species.
Branches and seed cones of Fraser fir collected by Garden staff in Virginia. Photo by Alanna Sanders.
Seeding the Future
Seed banking allows for some seeds, especially those from temperate climates, to be dried and frozen. The process can preserve seeds for decades until they are ready to be thawed and germinated to grow into new plants.
Garden horticulturists collected about 17,000 Fraser fir seeds in 2019 and added them to the Garden’s Seed Bank, housed at Shaw Nature Reserve. A year after going into a deep freeze the seeds were sampled for different types of viability testing—essentially trying to determine if the seed is “good” and could grow into a new plant, or “bad” and won’t.
Cleaned seeds of Abies fraseri prepared for storage in the Seed Bank. Photo by Meg Engelhardt.
In one set of tests, the seeds are thawed and sown into a growing medium. Temperature and light are controlled to mimic natural conditions, and staff simply count the number of seeds that germinate. The results weren’t great. Of the 80 or so seeds tested, only two successfully germinated. Most of the other seeds turned moldy or were empty to begin with.
A Revealing X-Ray
Another way to test potential viability involves taking a look inside the seed using an x-ray machine. Examining the seeds in this way reveals a possible cause for some of the low germination rates—infestation. Seeds from two different collection sites showed signs of insect damage that wasn’t apparent to the naked eye. The x-rays also backed up the results of the germination tests, by revealing some of the seeds were simply empty to begin with.
A selection of Fraser fir seeds as seen before and after x-ray. Photo by Brittany Shultz
The x-ray tests can help Seed Bank staff weed out nonviable seeds from the collection, ensuring the seeds in cold storage have a higher likelihood of germination. Small samples will be pulled out of the Seed Bank every five to ten years for continued testing.
The goal is to collect and store three to ten thousand viable seeds for this and all target species in the Seed Bank—enough to capture a broad snapshot of the genetic diversity found in the wild. If necessary, Garden staff could return to the field to collect additional seeds from other wild populations, in coordination with other groups working to conserve Fraser fir.
The Next Generation
Despite the challenges with seed viability, the Garden was able to add another layer to its conservation efforts by propagating eight seedlings. These baby Christmas trees are being cared for at the Oertli Family Hardy Plant Nursery, where they will overwinter in pots in one of the hoop houses.
An Abies fraseri seedling in the Hardy Plant Nursery. Photo by Cassidy Moody
Even if these tiny trees thrive during the cooler months, their future as mature trees is a bit less certain. Fraser firs prefer the cool altitudes of the Appalachian mountains and are unlikely to adapt well to the sweltering St. Louis summer heat.
Still, our horticulturists will care for the plants and monitor their progress, recording valuable data along the way that could prove useful for future conservation efforts. And of course, the seeds will remain secure in the Seed Bank—safeguarding this species for many Christmases to come.
Senior Digital Media Specialist