Saving whitebark and limber pine
Whitebark and limber pine are keystone species in mountain ecosystems. This means that the trees play a really important role. They provide food and shelter for wildlife, stabilize slopes and hold onto the snowpack. This makes water available to other plants and helps prevent flooding in the spring.
Currently, whitebark and limber pine face many challenges. The trees are in decline and at risk of extinction. The main threats are white pine blister rust (a non-native fungus), fire suppression, mountain pine beetle and climate change.
Planting the Future: Saving whitebark and limber pine
|Needles in bundles of five||Needles in bundles of five|
|Grows at or near treeline||Grows at slightly lower elevations|
|Cones are dark purple, 5-8 cm long||Cones are light brown, 7-15 cm long|
|Life span up to 1000 years||Life span up to 1000 years|
|SARA status: Endangered||SARA status: Recommended for listing as endangered by COSEWIC|
Whitebark and limber pine cones are an excellent food source. Hidden inside are nutritious seeds packed full of protein and fat. Many animals, like bears, squirrels and birds, rely on these seeds.
An important partnership
Clark’s nutcrackers play a key role in seed dispersal.
Whitebark pine cones do not open on their own. Instead, Clark’s nutcrackers use their long, pointy beaks to break apart cones and remove seeds. The birds eat some seeds and store leftovers in the ground for later. Forgotten seeds will grow into new trees.
Limber pine cones open on their own, but the wingless seeds still need help to move. Animals like Clark’s nutcrackers carry seeds to other locations where they grow into new trees.
Why are these trees in danger?
The deadliest threat: White pine blister rust
This fungal disease was introduced from Europe in the early 1900s. It has killed many whitebark and limber pine trees across North America. The fungus enters through the needles and then spreads, attacking tissue and disrupting the flow of nutrients. One sign of infection is orange "blisters" on the bark. Because the fungus was introduced from Europe, the trees here did not evolve with it. Less than 1% of whitebark and limber pine are naturally resistant to the rust.
- Fire suppression- Historically, forests burned more often but most fires were small and low-intensity. They created open, sunny spaces and good growing conditions for whitebark and limber pine. Past practices of extinguishing wildfires changed this. Many forests are now dense and shady. They provide poor habitat for whitebark and limber pine and fuel large, high-intensity fires.
- Mountain pine beetle- These beetles are a normal part of healthy forests in western Canada. A warming climate and fire suppression changed this. Beetle infestations now get bigger and spread to higher elevations. As a result, whitebark and limber pine trees are attacked more frequently than in the past.
- Climate change- Climate change affects mountain ecosystems in many different ways. For example, natural disturbances like fire, mountain pine beetle and drought are becoming more extreme. Also, tree species typically found at lower elevations are moving higher, competing for resources with whitebark and limber pine.
What is Parks Canada doing to help?
Seven national parks are working together to save whitebark and limber pine: Jasper, Banff, Yoho, Kootenay, Waterton Lakes, Mount Revelstoke and Glacier. Because the trees face multiple threats, we do a lot of different things to help.
Cone collection and planting
First, Parks Canada staff identify trees that show natural resistance to white pine blister rust. Then we climb the trees and put protective cages over some of the cones. When the cones are mature, we collect them and remove the seeds. Some seeds are sent to tree nurseries while others are saved in a seed bank. At the nurseries, it’s a waiting game. After two years of growing, many of the tiny seedlings are planted back in the national parks. The rest are sent for testing to see how resistant they are to blister rust.
Blister rust monitoring
Parks Canada has more than 300 long-term whitebark and limber pine health monitoring transects. They are located throughout the Canadian Rocky and Columbia mountains. We survey the transects every five years to see how blister rust infections are changing. Additionally, each park monitors their own “plus” trees (trees that show natural resistance to white pine blister rust), to see if they are staying healthy.
Fire is an important part of mountain ecosystems. It has many benefits for whitebark and limber pine, like removing other trees that compete for resources and creating openings that attract Clark’s nutcrackers. Parks Canada uses prescribed fires and wildfire management to return fire to the landscape. We also use mechanical thinning to open up space in areas where burning isn’t safe. Overall, this work creates good habitat and growing conditions for whitebark and limber pine.
Pheromones are chemicals that animals use to communicate. Parks Canada uses a natural chemical called verbenone to communicate with mountain pine beetles. We attach small packets of verbenone to high-value whitebark and limber pines trees. This protects the trees by telling beetles, “move along, this tree is already occupied!”
What we have achieved in the seven mountain national parks:
Updated April 21, 2022
- # of whitebark pine seedlings planted: 55,634
- # of limber pine seedlings planted: 12,689
- # of whitebark pine trees identified with possible rust-resistance: 773
- # of limber pine trees identified with possible rust-resistance: 75
- Habitat restored (with prescribed fire, mechanical thinning and planting): ~816 hectares
How you can help
Researchers use citizen science data from iNaturalist to understand where whitebark and limber pine grow, and which trees are infected by white pine blister rust. You can help too! Download the iNaturalist app and create an account. Learn to identify whitebark and limber pine and the signs of blister rust. Then, record your observations on your next hike in the mountains.
But always remember to be careful: Don’t injure or remove any parts of the tree!
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