Recovery of Endangered Whitebark Pine
By Alana Clason and Randy Moody
Whitebark pine cones. Photo: Alana Clason
Whitebark pine is an iconic tree found in mountains of western North America. From the Sierra Nevada to the Omineca Mountains in north-central British Columbia, whitebark pine has experienced widespread decline over the last century resulting in endangered status in Canada’s Species at Risk Act.
Whitebark greets those spending time in the mountains as they reach treeline elevations and often leaves a memorable impression, with its branching and sometimes gnarly forms. It has been used since time immemorial for traditional uses by Indigenous mountain peoples. Whitebark pine also welcomes many foragers. The seeds feed a rich network of wildlife from grizzly bears to squirrels – and most important, the Clark’s nutcracker. A bit bigger than a gray jay, Clark’s nutcrackers have the important job of being the only dispersal agent of whitebark pine seed. With an incredible spatial memory, nutcrackers cache thousands of seeds, and while they remember and feed on many of them, forgotten caches in suitable places establish new whitebark pine seedlings. This mutualism, a relationship where both species benefit from each other, is crucial to sustaining whitebark pine ecosystems, now and into the future.
“White pine blister rust effects whitebark pine across its entire range.”
Tree planter restoring whitebark pine after fire. Photo: Facundo Gastiazoro
Since white pine blister rust was introduced into North America over a century ago, five-needle pines have been exposed to the pathogen with little natural evolved defenses. White pine blister rust effects whitebark pine across its entire range, causing much of the decline and the focus of many of the recovery efforts. While whitebark pine is not resistant to the rust, there is variability in resistance, with some trees showing signs of better rust-resistance than others. If white pine blister rust was the only threat, then it is possible this important mountain tree species would evolve slowly through time to adapt to the pathogen. But persistent or eruptive outbreaks of mountain pine beetle and changing fire regimes also threaten whitebark pine. Fire suppression and the loss of Indigenous fire stewardship in whitebark pine habitats can reduce the amount of early seral or low-intensity fire that supports good establishment and growth conditions for whitebark pine. The larger emerging threat of fire, however, is through the increased frequency or severity of wildfire that can kill potential rust-resistant whitebark pine trees. Climate change may impact the ability for whitebark pine to compete for space in habitats it already occupies, while also increasing the threats from blister rust, mountain pine beetle, and fire.
Whitebark pine seeds drying. Photo: Facundo Gastiazoro
With such overwhelming loss, whitebark pine ecosystems need help. Recovery in this case is not just about the single species, but sustaining the ecosystem, and especially the mutualism between whitebark pine and Clark’s nutcrackers. We know relatively little about where, when, and under what conditions Clark’s nutcrackers visit many whitebark pine stands and populations throughout the mountains of western Canada. But we do know that ensuring adequate seed supplies to keep this disperser actively establishing trees will be key to sustain current and future populations of whitebark pine. To support Clark’s nutcrackers in the recovery of whitebark pine, many groups, partnerships and collaborations have now formed. In Canada, for example, we have the Whitebark Pine Ecosystem Foundation of Canada leading the way on recovery, in partnership with many First Nations, provincial and federal governments, non-profit, industry, local community groups, and more. Recovery of the ecosystem looks a lot like the ecosystem itself – a network of positive and supportive individuals and organizations working together to keep whitebark pine in and across our mountain landscapes.
Seedlings growing at Woodmere Nursery in Telkwa, B.C. Photo: Ingrid Farnell
Over the last decade, the art and science of whitebark pine restoration in Canada has exploded, with ever increasing expertise and experience building in each stage of recovery. We know more about how to identify the best trees – the ones that look rust-free in areas of high rust infection. We have an ever-increasing group of trained tree climbers, nurseries, and skilled planters to collect seed, grow seedlings, and plant them in appropriate sites. We have applied verbenone to reduce the likelihood of mountain pine beetle attack, especially on rust-resistant trees. We have worked with industry to reduce the number of trees impacted or restore these areas after impact. We have worked with commercial ski hills to increase awareness and decrease impacts to whitebark pine ecosystems within their tenures. We now have a rust screening program in Canada that feeds important information back to the cone collectors on which trees to collect from, and which to avoid. We have estab - lished seed orchards, where the most resistant trees are grafted to one day soon provide an increased supply of the most rust-resistant seed. And importantly, we continue to build and grow the network of knowledgeable and passionate people that started it all, care for, and continue to learn and improve whitebark pine restoration.
“What can ACC members do to help?”
A tree climber retrieving cones at the end of the season. Photo: Ingrid Farnell
What can ACC members do to help? What can any outdoor enthusiast do? Learn to identify whitebark pine and the rust that is killing it. Let us know where you see the tree and how healthy it is when you are out in the mountains. Sign up for iNaturalist and report your sightings along with photos. These observations will help build our knowledge of where the tree is and how healthy these stands are, which supports good recovery planning and action. It is possible that the trees you locate, and report, will become a part of the process of recovery for this important species.
Alana Clason, PhD, is a forest ecologist and research scientist based in Smithers, B.C., specializing in whitebark pine recovery and supporting forest management for multiple values. Randall Moody, MSc, is a Whitebark pine recovery specialist with twenty years experience. He is President and co-founder of the Whitebark Pine Ecosystem Foundation of Canada. He is based in Kimberley, B.C.