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Whistler’s treeline tragedy

The unfolding drama of a tree, a bird, and a foreign fungus

Prologue:

There’s a drama playing out in our picturesque mountains, with a plot and cast of characters from Ecology 101 as taught by Professor Shakespeare. Here’s a thumbnail sketch.

The co-dependent relationship of a tree and a bird are threatened when they are introduced to a foreigner. The tree, with no knowledge of the dangers of the foreigner’s seductive ways, lowers its defences. The foreigner quickly takes advantage and, in no time, the tree is dealt a mortal blow. The bird is distraught, flying back and forth. It sees the tree’s distress but is powerless to intervene.

The real-life inspiration for the story above is no less dramatic. The real cast? You’ve seen at least a couple of them up near treeline on Whistler or Blackcomb, or on countless peaks east to the Rockies.

Whitebark pine is the tragic hero. It really does have a co-dependent relationship with a bird, the Clark’s Nutcracker. And there really is an evil foreigner in this drama, white pine blister rust. Too bad it’s not suitably swarthy like Shakespeare’s or George W.’s villains. The orange complexion – a dead ringer for Kraft Dinner powder – is hard to launch a war over. But its kill rate makes Al Qaeda look tame.

What follows here is a behind-the-scenes look at the local angle to a real-life drama. It’s the story of a bird, a tree, and a villainous foreign fungus. It has impossibly beautiful vistas, decline and death, and a faint glimmer of hope for rebirth.

The Tree

If you’ve skied or hiked near treeline in Whistler, you’ve no doubt passed whitebark pines. They’re relatively easy to pick out in the crowd of subalpine firs at treeline. Subalpine fir has a thin profile – it’s the classic, conical tree on so many Christmas cards. Whitebark pine looks more like a giant broccoli – it’s the Rubenesque standout in a forest of Paris Hiltons.

In our mountains, whitebark pine is restricted to tough spots right near treeline, usually on sunny sites where other trees succumb to drought. The best place to find a lot of them is on 7th Heaven, but there are also pockets around Crystal Hut, Harmony Ridge, and the south side of Whistler (the Cakehole). East to the Rockies, they are more common and can be a dominant tree in the closed forest.

Whitebark pine is a critical member of the treeline ecosystem – a so-called keystone species. It helps stabilize soils and meter out water more slowly (by slowing melt) but, most importantly, its seeds drive a number of important relationships. The seeds provide a rich source of energy (one half fat, the other half carbohydrates and protein) in an ecosystem where food energy is not abundant. At least three major treeline animals rely on the seeds: Clark’s nutcracker, squirrels, and grizzly bears.

Squirrels gnaw off the cones and cache them for later eating, usually at the base of a tree. Grizzly bears are only too happy to search out these caches and eat the squirrels’ hard-won larders. Good seed years lead to improved reproductive success for grizzlies. Bad seed years bring them down into the valleys in search of food and often into trouble with humans. Whitebark pine seeds are also a favourite food for First Nations people.

From the tree’s perspective, squirrel caching is a dead end, even if it provides the neighbourhood with some sorely-needed nutrition. Most of these seeds are eaten by the squirrels, other rodents, or bears, and uneaten seeds are left to rot in places where they can’t germinate successfully. Which is why we need another character: the bird.

The Bird

The avian role in this drama is played by Clark’s nutcracker, a member of the Jay and Crow family. They superficially resemble whiskey jacks, but there are a couple of striking differences. First, there’s that magnificent black bill, at least twice as long as a whiskey jack’s. Second, they have black and white tail feathers that flash as they fly off. There’s usually one or two hanging around Pika’s or Crystal Hut looking for handouts in winter.

Unlike squirrels, the bird gives the tree what it wants. Nutcrackers collect the seeds (up to 100,000 in a season!) then cache them in early snowmelt sites for retrieval the following spring. The sites it chooses are ideal for whitebark pine regeneration: they’re open, melt out early, and support few competitors. Additionally, the bird perfectly plants the seeds one centimetre underground. Luckily for the tree and future nutcrackers, not all seeds are retrieved and some germinate to grow into new trees.

(There are probably a lot of reasons why some seeds aren’t retrieved, but it’s not due to any lack of nutcracker brainpower. Scientists comparing the spatial memory of nutcrackers to grad students always see the winner fly off.)

The tree and the bird made subtle changes over time to cement their mutual dependence, though it’s unclear which came first. Evolution gave the nutcracker a long bill as its main advantage over squirrels and other birds. Evolution also worked on whitebark pine to increase that advantage by changing its cones. Unlike the cones of other pines, whitebark’s are held aloft at the top of upward-pointing branches and they don’t open. These cones provide a perfect landing pad for nutcrackers while making it more difficult for squirrels and short-billed birds to get at the seeds inside.

The nature of the relationship between the tree and bird resembles that of Canada and Quebec: co-dependent but asymmetrical. Whitebark pine relies on nutcracker for its long-term survival – without the bird, the tree would not be able to regenerate. Luckily for them both, the bird is less dependent on their relationship. Cone crops are cyclical, which means the nutcrackers find other food sources in lean years. But when cones are plentiful, nutcrackers gladly forsake all others.

The Foreign Fungus

White pine blister rust is the foreign fungus in the drama. It arrived in North America in 1910 when someone – apparently thinking we were short in the tree department – imported infected French trees to Vancouver.

This fungus’ devastating impact on whitebark pine is yet another example in a long line of bad ideas, a line that includes the introduction of rabbits to Australia and zebra mussels to the Great Lakes. Over the past century, the fungus has spread continent-wide and now infects eight pine species.

Susceptible pines all have five needles per bundle. Two Whistler species are affected, western white pine and whitebark pine. Western white pines have taken a nasty hit – you can see dying and dead ones all around Whistler – but they have one big advantage. Unlike whitebark pines, they produce cones as early as seven years-old, and generally have at least a decade or two of cone production. Whitebark pine can take 50 to 80 years to first produce cones. There is a real danger young trees will be killed before reaching sexual maturity.

The fungus has two distinct stages. It alternates between pines and shrubs in the currant family ( Ribes species). In an attempt to break the cycle, U.S. land managers mid-century spent something like $400 million trying to eradicate currants. Unsurprisingly, the effort was a spectacular failure, not least because spores from currants can travel up to 300 km. It doesn’t take a lot of currants to infect a lot of pines.

The situation is bad, but what are the trends? Parks Canada’s Cyndi Smith recently resurveyed whitebark pines in Waterton, Banff, Jasper, and Yoho Parks and was dismayed with the results. In just eight years, 1996 to 2003, the proportion of infected trees increased from 43 per cent to 65 per cent, and the number of dead trees more than doubled, from 26 per cent to 60 per cent.

So far, numbers from B.C. have been lower but we don’t yet know how fast the infection is spreading. To help quantify trends, permanent plots were recently set up across B.C. by Stefan Zeglan, the Regional Pathologist with the Ministry of Forests. One of those plots is on 7th Heaven. Research money is scarce, though, especially because whitebark pine is not a commercially valuable timber species. Re-sampling for the Whistler plot isn’t scheduled until 2006 and only then will we have some hard numbers on local trends.

Act 2

The fungus has been in Europe long enough to have equilibrated, that is, for European pines and the fungus to have carved out an uneasy rapport. The fungus persists, but at a low enough rate for both the tree and the fungus to survive.

Here, the only obvious conclusion is that the future for whitebark pine is less than rosy, especially when other factors are thrown in. It can be killed by mountain pine beetle. It has suffered, at least in the U.S. Rockies, from fire suppression (fires create open spaces which favour whitebark pine). And, to top it off, climate change is likely to eliminate much of the treeline habitat in which whitebark pine grows. So can whitebark pine survive?

Diana Tomback is director of the Whitebark Pine Ecosystem Foundation and an expert on the interaction between nutcrackers and pines. In her opinion, "Local extirpation of whitebark pine is a real possibility within 50 years in some areas, but you can’t rule out total extinction entirely. The blister rust hasn’t yet stabilized."

Her colleague with the Ecosystem Foundation, Kate Kendall, agrees. "We need to intervene in a number of different ways," but she is quick to add intervention has challenges. For example, some areas have used prescribed burning to provide good sites for regeneration, but there may not be enough remaining trees to provide seeds.

Whistler’s Whitebark Pine Conservation Project

Local volunteer efforts began in 2000 with the Whistler Naturalists’ Whitebark Pine Conservation Project. Based on the ski hills, it has been funded by the Whistler-Blackcomb Employee Environmental Fund and helped with equipment from RMOW Parks and Whistler-Blackcomb.

Efforts to date have been pretty low-key, limited partly by the usual challenges of volunteer organizations, but also because it’s such an uncertain enterprise. Most of the effort has focussed on collecting cones, growing seedlings at a nursery, then planting them at treeline.

Volunteers planted 200 seedlings in 2002 and another 200 in 2003 (planting sites are beside the hiking trail on 7th Heaven). Seeds collected last year still haven’t germinated so no seedlings were planted this year. But since we didn’t find any cones this year, we will redouble efforts to coax those seeds to grow.

The planted seedlings are doing pretty well. Survival after one year is about 85 per cent, and two-year survival is about 65 per cent, not bad for two dry summers. But it will be a while before they grow to tree size – average height growth is less than 1 centimetre annually. Future plans include more planting and possibly some girdling of competing trees.

Epilogue

Things don’t look good for whitebark pine, a fact finally recognized at the highest levels. By this time next year, the federal government is likely to list it as an endangered species. And volunteer and government agencies throughout whitebark’s range will continue to try to prevent its eradication.

Meanwhile, volunteers do their best to keep whitebark in Whistler. Retired forester John Hammons sums his feelings up this way: "It’s an emotional response. We’re going to lose a really important tree in the high country, that’s what’s a real shame."

Bob Brett is a local ecologist and co-ordinator for the Whistler Naturalists’ whitebark project. His favourite whitebark pine is below Jersey Cream chair at the bottom of the Cafe Chutes.



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