Blister rust invades Lake Tahoe Basin trees
October 22, 2008
Peering up at a towering five needle pine tree in the Tahoe Basin you might not notice they are in danger. Take another look; you might see the man trying to save them.
John Pickett, Nevada Fire Safe Council Regional Chapter Coordinator and founder of the Sugar Pine Foundation, is at the forefront of a movement trying to regenerate healthy sugar pines, western white pines and whitebark pines in the Tahoe Basin.
Pickett currently fights white pine blister rust, an Asian fungal infection introduced in Western Canada at the turn of the 20th Century. It has since devastated forests in Canada, Washington, Oregon and California, killing 90 percent of the pines it infects.
“Blister rust is capable of adapting to a myriad of conditions because it can reproduce and mutate so quickly,” said Pickett “that’s always true of a non-native invasive species.”
A pine is infected through its stomata, a tiny pour on the pine needle, Pickett said.
The fungus then grows down the needle and into the bark where it begins to run its course. Along with its own damage, the infection will render the tree vulnerable to any pathogen that could harm it, Pickett said.
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“It’s inexorable, there’s no stopping it,” said Pickett. “Once the tree is infected its reproductive potential is gone and it will die.”
This inability to reproduce becomes a major concern considering trees at high elevations are crucial for snow storage. Pounded by harsh elements, high elevation slopes rely on trees to provide shade from direct sunlight and protection from wind.
Without these trees, slopes would be windswept and snow would melt, creating an excess of runoff the land is not capable of transporting.
“This is a problem for ski resorts,” said Pickett, “if they don’t do anything they’re not going to have trees to hold snow on the mountain.”
Making matters worse, high elevation five needle pines tend to be at a greater risk for contracting the fungus. High elevation trees have adapted to strong winds by growing needles closer to the tree and this adaptation makes it easier for the blister rust to get to the trunk.
While a percentage of sugar pines and western white pines are resistant to blister rust, whitebark pines are not. According to Pickett, the Whitebark Pine will cease to exist as a functional high elevation tree in the Tahoe Basin within 30 to 40 years.
Infected five needle pines are easy to detect by the presence of a “red flag,” Pickett said.
While blister rust usually infects the upper crown of a five needle pine, infected needles take on a brownish red color indicative of a “red flag” that covers the top part of the tree, Pickett said.
Pickett’s Sugar Pine Foundation aims to help regenerate pines resistant to blister rust by harvesting seedlings from naturally resistant pines and reintroducing them to be the natural seed trees of the future.
To harvest these seeds means Pickett must search for genetically resistant pines naturally found in the forest, a difficult task considering approximately 5 percent of all western white pines and sugar pines are able to tolerate blister rust. Whitebark pines are not able to fight the disease at all, Pickett said.
“We’ve been successful with grant funding and private donations,” said Pickett, “but we pay money to do this. It’s a labor of love.”
Pickett said restoration has begun this year with 3,000 resistant seedlings going to Tahoe City, Truckee, and the Angora Fire area.
50,000 seeds are currently being germinated at a Cal Forest Nursery.
“Sugar pines like a lot of light,” said Pickett, adding that an area of private land with good sunlight is an ideal situation.
Pickett currently offers resistant five needle pine seedlings on the Sugar Pine Foundation website for private purchase. Residents can purchase seeds for $20 and be a part of the restoration by planting sugar pines on their property.
“This is not just about landscapes,” said Pickett, “entire forests are disappearing.”
For a better look at the effect of White Pine Blister Rust, hike the Ellis Peak Trail in Blackwood Canyon and look for the “red flags” that top diseased five needle pines.
Five needle pines can be identified by having five needles per bundle on a branch.
While dead needles at the base of the tree usually indicates a temporary lack of sunlight, dead needles topping the tree means it is infected.
Recently dead needles show how much the blister rust has destroyed in the past year. It will take several years for the disease to fully kill the tree.
Buy resistant pine seedlings, donate money or keep up with the restoration project at http://www.sugarpinefoundation.org.