Waterton Lakes National Park of Canada

Green Scene - Whitebark Woes

Whitebark Pine
© Parks Canada

High up on a mountain slope a sturdy whitebark pine stands its ground against the elements. While it might appear out of place in this rocky, windswept habitat , the whitebark pine has evolved over time to become an important tree of the high elevation forests along the Rocky Mountain chain.

This Subalpine tree is easily recognized by its needles, which grow in bundles of five, and its large cones. Whitebark pines stabilize steep slopes, influence the amount of snow melt by sustaining snow drifts, and provide critical food, cover and shelter for many species of wildlife. Its loss could change the Rocky Mountain subalpine ecosystem , as we know it today.

Unfortunately change is happening quickly. As hardy as the whitebark pine is, it is declining throughout the Crown of the Continent ecosystem, including within Waterton Lakes National Park. Its survival has been threatened by the combined effects of fire suppression, mountain pine beetle outbreaks and a disease known as white pine blister rust.

An old friend to wildlife

Clark's Nutcracker
© Parks Canada

Slow growing, a whitebark pine may not produce cones until it is over 50 years old. When the cones do develop, their seeds, which are similar to the pine nuts sold in stores, are an important source of protein for a variety of species including the Clark's nutcracker, red squirrel, and grizzly bears.

Whitebark pine and the Clark's nutcracker have evolved together, and depend on each other for survival. Whitebark pine cones do not open and scatter their seeds on their own. Instead, the tree relies on the ability of the nutcracker, with its long pointed beak, to break apart the cone to get to the seeds. The Clark's nutcracker has a pouch under its tongue capable of holding dozens of seeds. It then looks for suitable storage places, typically open, sunny areas that are likely to remain snow-free and available for seed retrieval earlier than forested areas. Coincidentally these locations are also great places for whitebark pines to grow.

Capable of caching a thousand seeds a year, the nutcracker marks each site with an array of sticks and stones. It uses these unique 'memory maps' to relocate each stash. Still, roughly half the caches are overlooked and many of these forgotten seeds grow into pine seedlings. Thus, the Clark's nutcracker becomes a gardener, creating a food source for its next generations.

Firing up restoration

Whitebark pines are one of the first trees to establish after a fire. As the forest regenerates, other tree species may eventually shade out this sun-loving species, so natural disturbances can reset the successional clock to favour both the nutcracker and the whitebark pine. Fires create openings in the forest canopy and nutrient-rich seed beds, which attract nutcrackers as ideal areas for seed storage. These conditions give the whitebarks a competitive edge over other cone-bearing trees in the subalpine.

Historically Rocky Mountain subalpine forests burned every 90 to 300 years. Most fires were low intensity, small and patchy. They created open spaces suitable for the nutcracker and whitebark pine. Former fire suppression practices reduced the number of these important open spaces, hindering growth of new whitebark pines, and allowed older, even-aged lodgepole pine stands to prevail at lower elevations. In the absence of fire, these lodgepole pine stands are prone to epidemics of mountain pine beetle. As the pine beetle epidemic has been intensified due to human influences, it has spread into the higher elevation whitebark pine stands.

Yet another enemy

To add to these concerns, the whitebark pine is now facing a new menace. In 1906, a shipment of white pine seedlings arrived in New York from Europe. The seedlings carried white pine blister rust to a continent where native pine trees have no natural resistance. The consequences for North America's five-needle pines has been severe. Kate Kendall, a research ecologist who led a project to study these pines in the Waterton-Glacier area, has stated, "Whitebark pine is functionally extinct in many areas." Not only has a large percentage of the trees already died, but most of the survivors are infected.

Less than 1% of all whitebark pines are rust resistant. It is important to create the best conditions for many new whitebark pines to grow. The more that are grown, the more likely that some with rust resistance will survive and thrive. These would produce new pines with higher rates of rust resistance. To do this, active creation of suitable open areas near mature seed producing trees is needed, preferably through use of fire.

What Parks Canada is doing

Waterton is evaluating the use of prescribed fires or artificially creating small open areas, to revitalize the whitebark pine. Waterton is also undertaking a whitebark pine ecosystem restoration research program. The information gathered will contribute to refining management practices used to restore this key threatened species.

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