Seeding hope for limber pines.

If you’ve ever been to the Crowsnest Pass region of southwestern Alberta, you’ve undoubtedly seen the so-called “Burmis tree,” a seriously craggy specimen of limber pine that actually died in the late 1970s, when it was between 600 and 750 years old.  It fell over in 1998, but it stands today due to the devotion of the people of Burmis, who, with a few props, have re-erected the wooden monument.  The Burmis tree is a particularly amazing and strangely beautiful specimen to see and photograph due to its krummholz growth habit, which happens when trees are isolated and exposed to constant, intense winds, such as those coming off the mountains in the Pass. Limber pines growing in such conditions become severely stunted, unable to reach their maximum height of 15 m, but their branches grow long and horizontal, twisting out sideways like some oddity out of a Tim Burton movie.  Needleless and long deceased and relying on support to keep it upright, the Burmis tree is certainly an interesting tourist attraction.  (It’s really quite impressive – due to its particular placement on the rocky ridge and the fact that it is completely alone in a totally treeless area, it stands out as a real visual treat).

Unfortunately, the Burmis tree has been a reluctant symbol of the decline of the entire limber pine population in Alberta.  There simply aren’t many limber pine stands left.  They grow primarily in montane regions, where they are one of the few trees that can withstand the severe winds, extreme drought, and shifts in weather that occur, and they have an impressive lifespan, easily reaching a ripe old age of 750 years or more…if they don’t succumb to fire or any number of diseases and pests.  Limber pine (and their look-alikes, whitebark pines) are susceptible to something called white pine blister rust, which is infecting a high rate of trees, causing puffy blisters which for some reason red squirrels like to chew on.  Open wounds in the trees can result in mortality.  In the 1970s and 1980s limber pine stands were ravaged by mountain pine beetle, but although that threat has so far remained distant, trees weakened by blister rust will undoubtedly be the first to go should mountain pine beetles decide to invade.  Adding insult to injury, there is a slight threat of the parasitic plant limber pine dwarf mistletoe (Areceuthobium cyanocarpum) creeping somehow across the border from Montana, where it has harmed some trees.

There are other factors that don’t make life easy for limber pines.  It seems that individual trees do not reproduce until they are at least fifty years old, and once they do produce seed cones, the squirrels get ’em…BEFORE the seed becomes viable.  Apparently squirrels are hasty critters (true in every way) and they seize the green cones off the trees instead of letting the seeds ripen and mature.  Because of this, there is little chance that the seed will disperse and produce more trees.  Leftover seed that is allowed to mature is often consumed by grizzly and black bears, who find them nutritious components of fine dining before their winter siestas.  Out of the remnants of squirrel and bear meals, the small amount of remaining viable seed is dispersed by birds – in particular, one species called Clark’s nutcracker.  Sort of the little avian saviour of the limber pine, the Clark’s nutcracker mines the seed from the open pine cones in early autumn and then flies away to bury each seed in little caches.  The birds know the best locations to bury their private seed stashes, so that the snow will not completely cover them, but of course the birds cannot recall the exact position of all of their storehouses and young trees subsequently take root.   But the Clark’s nutcracker also faces difficulty:  in 2005, due to its strict dietary dependence on limber and whitebark pines and susceptibility to West Nile virus, the bird was placed on the “Sensitive” list.  Grim, indeed, but it clearly illustrates the direct link between animals and plants within an ecosystem.

But there may be hope for the limber pines.  According to an article in the Edmonton Journal (and subsequently shared by the Calgary Herald) on 16 January 2011, a biologist from The King’s University College announced that an unusual bounty of pine cones had been produced in the previous autumn by the stands of limber pines he had been monitoring.  Apparently his take on the huge bumper crop of cones is that the pines are doing this every few years to “outwit” predator squirrels.  (Yep, I said it.  “Predator squirrels.”  Sounds like the premise for a really bad horror flick).  Every few years, the trees simply produce so many cones that the squirrels can’t consume all of them.  I’m thinking that whether or not this is an accurate theory, it certainly gives insight into the survival mode of a living organism under pressure.   Apparently Alberta Sustainable Resource Development  is working on a recovery program for limber pines, which may include the introduction of trees grown in nurseries, but, considering the extraordinary lifespan of these trees, this is obviously an (ahem!) long-term project.  Let’s hope for wild success.

***

I admit to some confusion when trying to uncover information about the oldest living tree in Alberta.  In Alberta’s centennial year, 2005, the provincial government created a Trees of Renown Program, and the first tree inducted into this hall of fame was a limber pine from the Crowsnest Pass area that is purported to be 1,100 years old.  But apparently there is a whitebark pine on the banks of the North Saskatchewan River somewhere in Banff (a place called Whirlpool Point) that is 1,200 years old.  You can see its photograph at www.gigapan.org/gigapans/30245/.  The exposed root system on it is incredible!  So I don’t know.  Anyone have any other information or photos?

***

A great photo of the Burmis tree is at www.redbubble.com/people/diamondwillow/art/322771-15-sunset-at-the-burmis-tree.  There are hundreds of photos of this thing on the ‘Net.  Send me a link to yours.

***

The Herald article is at www.calgaryherald.com/technology/Evolutionary+quirk+help+save+endangered+Alberta+trees/4117332/story.html.

More info about limber pines can be found at Alberta Sustainable Resource Development:

www.srd.alberta.ca/biodiversitystewardsip/speciesatrisk/DetailedStatus/documents/limberpine.pdf

www.srd.alberta.ca/MapsFormsPublications/Publications/documents/April00.pdf.

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