Friday, April 08, 2011

Water hogs

Along the banks of the rivers in the delta, towering over the big-leaf maples on the cliffs overlooking the seashore, wetting their feet in duck ponds and soggy watersheds, our cottonwoods - black cottonwood, Populus trichocarpa - draw our skyline. (Or distant mountain line, if we're looking north or east.) In a month or so, they'll be providing "snow" to delight children (and me) all over the Lower Mainland, and nesting sites for birds from hummingbirds  to eagles, owls, and ospreys. Some of the birds will use the "down" (aka the "snow") from the ripe seeds to line their nests.

I often take photos; they rarely amount to anything. The trees are so tall (up to 50 metres) that to get a full view, we have to be on the other side of the river. Close up, the branches start far overhead; they block our view of the leaves and catkins; at eye level we see only rough, fissured bark, lichen and moss.

Dawdling around Centennial Park last week, I decided to photograph one tree from my normal vantage point.

There are buds on the tips of branches far above. If you look really closely, you might see a few.

Bark on an old tree. Young ones aren't quite so craggy.

Root tops, cut where they broke the surface.

The cottonwood is a water hog. The roots go far afield, close to the surface to catch every drop of rain, breaking ground to reach into rivers and ponds. When one of these roots is cut, it will leak for days.

20-some years ago, I was living up north, in Bella Coola. I had been too long in the cities; I had a lot to learn. Coming into my first winter, I was prepared, I thought; I had asked for advice, and filled the woodshed with the appropriate number of cords of firewood for our two stoves. Good dry alder off our own slopes, aromatic cedar for kindling, and plenty of big cottonwood logs for steady heat overnight. (They do say it makes good firewood.)

I didn't realize that cottonwood may take a year to dry. In the middle of the winter, with the temperature outside at -20 degrees Celsius, our alder supplies were running low, and we brought in the cottonwood. In the hot stove, it hissed and sang, dripping steaming water onto the coals, sometimes putting the fire out altogether. Even in the woodbox next to the airtight stove, the cottonwood logs leaked, leaving the woodbox sitting in a puddle.

I took to putting logs on top of the stove, while alder burned inside. The cottonwood dripped, even there, for hours, but eventually it was burnable. We didn't freeze; we made it through to spring. But the next year, the woodshed was full of alder.

At Centennial Park, every tree is numbered.

Lichens, grey-green and bright yellow cover the old bark.

More lichen.

I stepped back to where I could see the top. These big branches break off easily; most older cottonwoods bear the scars of departed limbs.

One other thing about cottonwoods; they're easy to plant. Grab one of the broken branches, or twigs, or a piece of root. Shove it in wet ground and leave it; it will sprout and grow quickly. The fallen branches sprout where they lie, or float down the river and sprout where they land, rapidly forming small forests wherever they find sun and water, plenty of water.


  1. I miss cottonwoods...I've only seen a few here. I thought it must be too cold, but now I think it is too dry, other than around lakes and rivers.

    But I do miss seeing the wispy 'snow' that falls every year!

  2. they're terrible for my hubby's allergies, but we have several along our pond. they do take a lot of water. i gather their spent twigs for fire kindling and they always spark and hiss at me. :)

  3. Cottonwood's are amazing. I only know about the Southern Cottonwoods and I know they don't have this slurpy affect, of which you speak. At least I have never seen this. Of course, with a different specie of cottonwood comes a completely different characteristic. I do know that on the plains, in the US, if one sees a cottonwood from a bit of a distance, they can be sure that there's water somewhere around the tree itself. You may have to dig for a while, but you will definitely find water.


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