Over the last few weeks, Edmonton trees have been putting on their best show with myriad colours of autumn. The leaves have pretty much fallen now, and the trees are entering their winter hibernation phase.

The glorious display of the last few weeks reminded me just how fortunate we are to live in a city with so many trees. In the river valley and adjoining ravines, parks, on wide boulevards and private property, a diverse roster of tree species make Edmonton one of the most treed cities in the country.

Edmonton's tree inventory, which includes 167,000 roadway buffer and park trees and 117,000 boulevard trees, is valued at more than $870 million dollars. The city's urban forest is comprised, in natural areas, of three major species - 30 per cent aspen, 35 per cent balsam poplar and 15 per cent white spruce. On boulevards, the proportion is 40 per cent green ash, 35 per cent American elm and 15 per cent black ash.

The province-wide Elm tree inventory, conducted in 1999, found that Edmonton has the largest concentration of elms in the province, with more than 65,000 of them. That compares with 30,000 in Calgary, 8,000 each in Lethbridge and Medicine Hat and 5,800 in St. Albert.

These elms are susceptible to Dutch Elm Disease, which has destroyed millions of American elm trees across North America. Edmonton has one of the largest concentrations of healthy American elms in the world and the city is working hard to keep it that way.

An isolated case of Dutch Elm Disease was discovered in Wainwright, Alberta in 1998. Although Alberta is still disease free, the beetles, which carry the disease, have been found in Edmonton and St. Albert (since 1995), Calgary (since 1994), and Vauxhall (since 1996). Dutch Elm Disease arrives three to seven years after the first detection of elm bark beetles. Trees grown in Edmonton that are susceptible include the American Elm, Ascending American or Brandon Elm, Siberian or Manchurian Elm, and the Japanese Elm.

It will take diligence and awareness to prevent the spread of the disease in Edmonton. (More on that at the end of this article). Such awareness is what saved one downtown horse chestnut from death. The tree, in a parking lot just off 106th Street and Jasper Avenue, is the last surviving remnant from the Holowach yard.

The tree found its way onto the Register of Historic Resources during a 1993 inventory and its listing as a landscape resource brought its imminent demise to the attention of city planners. With the cooperation of the Hong Kong Bank of Canada, the horse chestnut has been saved and now sports a metal fence to protect it from wayward automobiles.

Stands of significant trees listed under the "landscape resources" category of the Register include the boulevard and median Green Ash and Manitoba Maples on 97th Street between 111th and 118th Avenues. Other are the American Elms on 82nd Avenue between 96th and 99th Streets and then 109th and 112th Streets.

Individual trees already identified on the Register include Garneau's Tree at 111th Street and Saskatchewan Drive (which may have begun life as early as 1874), the Stark Oak at the Provincial Museum. At the Muttart Conservatory, significant specimens include the Red Cross Tree and the St. John Ambulance Tree.

The Great Edmonton Tree Hunt, conducted in 1999, found that Edmontonians love their trees and take great pride of ownership in them. Submissions were received from all over the city.

The street I used to live on in Bellevue is graced with 55-year-old American elms. They've grown to be grand and stately and yet, in the lifespan of their species, they are mere teenagers. American elms can live 200 to 300 years. If we protect them, they'll be around long after we're gone.

American elms are wonderful urban trees: disease resistant (save for that darned Dutch Elm Disease) and able to withstand the rigours of climate and the occasional bump by a car. They spread out with an assurance that says, "Look at me, I'm a tree."

I can't believe it's been more than 35 years since I first became aware of the power and impact of those trees along 97th Street. I can remember gazing skyward through the rear window of my parent's 1960 Ford as we travelled along the road, the dappled light tumbling through a vast canopy of leaves and being transfixed by the beauty and enormity of these giant living creatures.

Even now, as I turn onto the street, the memories and the feelings come rushing back. Trees are comfort.

It's sad to think that we once had many more stands of these friendly giants and, over the years, they've been lost in the shortsighted rush of development. When the city chopped down some grand old trees along 100th Avenue in the early-1990s, citizens were rightfully outraged. There are dozens of other sad but true examples of losing such precious parts of our urban landscape.

Including trees on the Register of Historic Resources acknowledges that they are as historically important as built treasures like the Alberta Legislature or the Macdonald Hotel. They define our city, the define our neighbourhoods, they give life and character to our streets.

Beyond aesthetics, they perform a vital role for the planet, the air we breathe. They make Edmonton a much better place to live.

You Can Help Prevent Dutch Elm Disease

* Monitor the condition of the elm trees in your neighbourhood. Report any damaged elm trees that require pruning to River Valley, Forestry and Environmental Services main office at (780) 496-8733.

* Watch for these symptoms of Dutch elm disease:
Drooping and yellowing leaves in summer.
Branches with smaller leaves than rest of tree.
Branches with no leaves.

* If you suspect DED, please call the City's DED Hotline at (780) 496-6905.