Grasses and forbs must first create enough ground cover to hold soil moisture. Then it takes an additional 20 to 40 years before seedlings become functional trees. And then 20 more years before they start producing cones. Healthy Ecosystem Whitebark pine thrives in the subalpine regions of the western U.S. and Canada. The fire-tolerant pine produces an abundance of nuts, which are eaten and stashed by Clark's nutcrackers, right.
Nutcrackers bury caches of nuts in loose soil on the mountainside.
Bears travel to the high country in the summer in search of nutcracker stashes. Intermittent fires scorch back competing subalpine fir trees. Fires also loosen soil, which is ideal for nutcracker caches. Nut stores, which are forgotten and undiscovered, sprout into clusters of young pine trees. An introduced fungus, white pine blister rust, has weakened many pines to the extent that they can no longer exude enough sap to defend themselves against mountain pine beetles.