Caging cones: Investing in a future for whitebark pine

A cross-section of an immature pine cone reveals the seeds developing inside.

A small vault, filled with neatly-ordered rows of seeds, with the potential to repopulate a forest — that could be a description for a pine cone, but it also describes the Dorena Genetic Research Center on the Umpqua National Forest.

“People have no idea,” Haley Smith, seed program coordinator for the research center, said. “We have a really valuable resource on the Umpqua, our seed bank, that’s been here for 50 years.”

For Smith, the Dorena Genetic Research Center is a place where suiting up to saving a tree species could mean donning a snowsuit rated to resist the freezer’s subzero chill, or strapping into a harness to scale trees in search of the cones that have given rise to a catalog that’s now 250 million seeds strong, and counting.

An employee wears a snowsuit and gloves to retrieve a drawer from a large storage freezer

Haley Smith retrieves seeds stored in a specialized seed-storage freezer at the Dorena Genetic Research Center on the Umpqua National Forest, Oregon, in an undated photo. This freezer stores 250 million seeds, collected from 35 species. The center also stores seeds for dozens of additional species in a separate cooler. USDA Forest Service photo (provided by Haley Smith).

In July, Smith was among a small team of Forest Service employees collecting seed for the bank from a stand of whitebark pines, Pinus albicaulus, perched high on the Umpqua National Forest’s Tipsoo Peak July 26.

Several of the trees had proved resistant in previous testing against White pine blister rust, an invasive fungus that has blighted stands of five-needle pines for more than a century.

The fungus, Cronartium ribicola, originated in China and arrived in the continental U.S. at the turn of the last century, where it quickly established itself on both coasts and began to spread. It reached in southern Oregon by the 1950s, and arrived in Colorado a decade ago.

“It’s still on the move,” Joshua Bronson, a plant pathologist for the Southwest Oregon Forest Insect & Disease Service Center, stationed on the Rogue River-Siskiyou National Forest, said.

Bronson helped organize the Tipsoo Peak cone-caging expedition.

“All of the high-altitude species are a concern to scientists, as we monitor the effects of the warming climate,” he said. “But with the disease, this one is especially urgent.”

A view of a climber in a tree, placing hardware cloth cages on developing pine cones.

An unidentified USDA Forest Service employee places cone cages on a whitebark pine tree on the Fremont-Winema National Forest July 18, 2015. The cages are used to protect cones from wildlife until harvesters return to collect their seeds later in the season. USDA Forest Service photo by Haley Smith.

A half-century ago, initial investments into research into white pine blister rust resistance often focused on Western white pine and sugar pine, species important to the region’s timber industry, Robin Darbyshire, a silviculturist for the USDA Forest Service’s Pacific Northwest regional office, said.

In contrast, whitebark pine is found in alpine environments that are often too steep or environmentally-sensitive to log. Yet it brings extraordinary value to the forest in other ways.

The tree is considered a “nursery species” because it creates shade and shelter for other plants at those high elevations, Darbyshire said.

Its seeds are high in fat and protein, a prize for any creature trying to survive in the wild.

“It’s really the iconic tree at higher elevations, like around Timberline Lodge. There’s also a bird, Clark’s nutcracker, that’s dependent on the seeds,” she said.

In fact, the tree is also dependent on the birds. To reduce competition, the pine has evolved a tough cone that keeps most critters away – but also prevents its seeds from sprouting, without an assist from the outside.

“(The nutcrackers) have these long bills that can get in there to get at the seeds,” Darbyshire said. “They’re the only species that can get in there. Maybe a bear could crack them open, but, that’s about it.”

And if the cones aren’t opened, the seeds inside won’t germinate, she said

This symbiotic relationship is just one of the intricate ecological dependencies threatened by white pine blister rust.

A pine tree, with a single branch blighted by White pine blister rust, is visible in the foreground against a panoramic view of mountain peaks and a lake.

Mount Thielsen and Diamond Lake are visible in this view from Tipsoo Peak on the Umpqua National Forest, taken during a cone-caging expedition, July 26, 2018, in preparation for harvesting seed later this year. A single branch of whitebark pine tree in the foreground has been damaged by white pine blister rust, a fungus that has blighted stands of several five-needle pine species since it was introduced to North America about a century ago. Researchers are working to identify and collect seed from trees with disease-resistant characteristics in an effort to help repopulate lost stands and prevent the species’ extinction. USDA Forest Service photo by Joshua Bronson.

The fungus bores into the tree’s twigs and needles, developing spores that erupt from blisters on its bark and spreading to low-growing carrier plants, which carry it between stands and make the disease difficult to contain or eradicate when it enters a new area.

The infections leave scars, or “cankers,” that cut-off the flow of water and nutrients in a branch. Eventually, enough branches die to kill the tree, or the tree is weakened enough that it falls victim to insects, drought, or other stresses that finish the job.

In 1966, Forest Service researchers at the Dorena Genetic Research Center began collecting seeds and genetic material from five-leafed of pines, in an effort to test individual trees for disease-resistance, and clone or breed the most disease-resistant trees.

Today, the lab’s staff continues that work. They also breed Port Orford cedar for resistance to a root disease, and manage the USDA Forest Service’s National Tree Climbing program.

The systematic cultivation, testing, and breeding for disease-resistance is painstaking work.

A hand holds an individually potted, labeled seedling, lifted from a larger batch of seedlings on a tree nursery table

Whitebark pine seedlings, in a July 25, 2018 photo taken at the Dorena Seed Research Center nursery. Seeds are pre-treated to convince they’re going through winter, a process called “stratification,” then germinated under controlled conditions. White bark pine’s stratification process takes 120-140 days. “That has the tag for a tree that I climbed on, it’s a tree on Mt. Bailey,” Haley Smith, Seed Program Coordinator for the center, said. The seeds underwent stratification in November, 2017, and planted in April, 2018. If grown for testing, they will be exposed to clouds of white pine blister rust spores and monitored for disease-resistance to assign the parent tree a “letter grade” to determine whether the tree should be tracked for future harvests, which may occur every seven to ten years. If the seed is from a previously-tested tree, they could also be used to replant when tree stands lost to disease or fire. “Clones” grown from clippings taken from disease resistant trees can also be grafted to mature root stock and used to establish an “orchard” for future seed harvests. USDA Forest Service photo by Haley Smith.

“We have (seeds) that have been collected since the sixties. And for each of those trees, we know exactly which one it is, where it’s located, where the ‘mom’ tree is – or was, it may not even be there anymore,” Smith said. “If it’s one we bred in our nursery, we might even know which ‘dad’ the pollen came from.”

But before any of that can happen, someone has to collect those seeds.

A woman in a hard hat smiles in a

Haley Smith shoots a selfie while caging pine cones for later seed harvest in a stand of White bark pine being monitored for White pine blister rust-resistance on Tipsoo Peak, Umpqua National Forest, Oregon July 26, 2018. USDA Forest Service photo by Haley Smith.

At Tipsoo Peak, Bronson and Smith were joined by Kayla Herriman, manager of the USDA Forest Service – Pacific Northwest Region seed extractory on Deschutes National Forest; Russell Oakes, silviculturalist for the Umpqua National Forest; Zachary Dimare, a Forestry Technician on the Umpqua; and Skylar Hamilton, an intern at Dorena.

The team hiked to the peak, a climb of approximately 1,500 feet, each carrying up to 80 pounds of outdoor essentials, climbing gear, and wire cages to protect selected cones from hungry nutcrackers until they return for the harvest.

“Whitebark pine is one of my favorite trees to climb. It’s got wide open branches, and it grows in places that tend to have incredible views,” Smith said.

Dimare said the long hike, heavy pack, and climb into the treetops at Tipsoo Peak was almost worth it, just for that view.

“It’s really dramatic up there. You can imagine you’re at the top of the world,” he said.

It’s hard to put a price tag on those drawers of seeds in storage at Dorena, but one measure is the labor cost that goes into collecting the seeds — seeds which are perishable, and must be constantly replenished.

It takes at least three trips to a stand of trees to harvest their seeds. Bronson’s first hike to scout the site is an annual requirement, to ensure if the stand’s cone and seed production is on track to produce enough seeds for a harvest.

It’s a trip that is repeated many times each year, often without results. For the whitebark pine, an individual stand of trees produce a crop sufficient to be harvested for seed only about once in every seven-to-ten years. If successful, a cone-caging trip follows, and then a third trip to collect the harvest — hopefully, before the snow falls.

Once collected, the supply of stored seed must constantly replenished. Conifer seeds keep five to fifteen years in storage, but it takes ten to fifteen years for seeds, once germinated, to grow into a tree capable of producing seeds of its own; even if they are grafted to mature root stock to accelerate the process.

Hardware cloth bags cover pine cones in a tree on a mountainside.

Hardware cloth bags protect White bark pine cones identified for later seed harvesting on Umpqua National Forest, Oregon July 26, 2018. USDA Forest Service photo by Haley Smith.

Participants in the Tipsoo Peak expedition caged cones on five whitebark pines; four that had been previously tested for white pine blister rust disease-resistance. The fifth tree’s seeds, when gathered, will be tested — a process that entails germinating trays of seedlings, isolating them, and then inoculating them in a cloud of white pine blister rust spores, and watching to see how quickly they succumb to the disease

“The major limiting factor, besides access to the trees, is how many of the cages we can carry,” Bronson said. “We can’t cage everything… I’m hoping we can get at least 30 cones from each of these, and by the looks of it we may have up to 50 from some of them.”

With similar expeditions taking place on forests across the Pacific Northwest, the region’s seed program  is on track to harvest 700 bushels of cones from various species, or approximately 550 pounds of seeds, this year, Darbyshire said.

A yellow sign nailed to a blazed tree reads:

Durable signage marks a tree being monitored for disease-resistant characteristics on the Fremont-Winema National Forest July 18, 2018. Some forests have “orchards” of trees, grown from seeds or clones of trees that have previously proved to be disease-resistant, to increase the supply of seed stock available for re-planting and future survivability of at-risk species. USDA Forest Service photo by Haley Smith.

While the work is arduous, the need for seeds is critical. Forest seed program managers try to keep a 10-year supply of seed in stock at any time. Many are used to restore areas impacted by severe wildfire, and a bad season can easily reduce those stores to just a 1-2 year supply.

The loss of trees to fungus and the race to establish more disease-resistant stands only adds to that urgency when it comes to replacing White bark pines. While it was one of the first trees studied, it took researchers years just to figure out how to germinate its seeds.

“These trees grow in such a harsh environment. You really have to convince them that conditions are just right for them to grow,” Smith said.

Once a tree’s seeds are collected and it’s seeds germinated and tested for disease-resistance in a lab, scientists must to wait years until the parent tree again produces enough seeds to collect, plant, and raise into trees that are again ready to harvest seeds from.

The entire process can take decades, if it can be completed at all.

Darbyshire said she has helped harvest seeds from trees she planted at the beginning of her career. “I never thought that would happen, it’s an incredible feeling,” she said.

On the other hand, she’s also seen trees planted in hope of future harvests consumed by wildfires.

“If we lose orchard, that’s a really hard loss. We’ve invested so many years in those trees,” she said.

While the research investment represented by any single tree enrolled in the genetics program is enormous, the work required to collect even a single seed is probably more than most people would imagine, Smith said.

“When you think about how long it takes for us to climb those trees… that was days of preparation, that was several people in the field all day, and then we come back, and clean the seed,” she said. Seed is stored in an envelopes, each organized by tree and by year.

“There are 20 little envelopes in each one of the drawers. It’s a ton of work, in each one of those little envelopes. And I’ll produce about eight of those drawers in one year,” she said.

A person in a climbing harness places a metal mesh bag in a White bark pine tree.

Zachary Dimare, a forestry technician on the Umpqua National Forests, places a hardware cloth cage over a whitebark pine cone to protect it for later collection during a seed-caging expedition on the forest’s Tipsoo Peak July 26, 2018. The seed is the primary food source for Clark’s nutcracker, one of the few species that can penetrate its cones’ tough exterior. USDA Forest Service photo by Joshua Bronson.

A climber, sitting on a tree limb, places a metal mesh bag on a pine cone

Russell Oakes, a silviculturist for the Umpqua National Forest, places a hardware cloth cage over a whitebark pine cone to protect it for later collection during a seed-caging expedition on the forest’s Tipsoo Peak July 26, 2018. USDA Forest Service photo by Haley Smith.

After more than fifty years, these efforts – and many more like them – add up to an  investment that could decide the future of the species.

Whitebark pine is not currently listed for protection under the Endangered Species Act, though it remains a candidate for future listing.

Scientists have said without intervention, it could become extinct in its native range within the next 100 years.

Dimare said that knowing he is helping make a difference in the species’ chances for survival is one reason he volunteered to become certified as a climber.

“I’m a forestry tech. I spend most of my time cruising timber and marking trees (for cutting). But these trees need our help to survive,” he said.

Cover photo: Seed collectors perform a “cut-face test” cones to determine if a tree is producing cones with sufficient, healthy seeds to harvest. For white bark pine, the standard is least eight viable seeds on the cut face, which means the cone contains an estimated 40 to 75 healthy seeds. USDA Forest Service photo by Joshua Bronson.

For more photos from the Dorena Genetic Resource Center, visit the USDA Forest Service Pacific Northwest Forest Health Flickr album:
https://www.flickr.com/photos/151887236@N05/albums/72157670761346628


Source information: Catherine “Cat” Caruso is the strategic communication lead for the USDA Forest Service – Pacific Northwest Region’s Office of Communications and Community Engagement, and edits the “Your Northwest Forests” blog. You can reach her at ccaruso@fs.fed.us.

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