David Allen Sibley's favorite Northwest trees

It's the time of year when fog in the morning foreshadows the chill and squishy gloom to come, when a walk in the woods becomes not just a necessity, but a demand. Here to help is David Allen Sibley, author of the just published "The Sibley Guide to Trees" (Knopf,$39.95).

Sibley is the author and illustrator of the classic "The Sibley Guide to Birds" (700,000 copies in print), a model of clarity in both text and illustration. He's in town this week for a reading at Third Place Books — hoping to get up and out myself, I rang him up to ask him about his favorite Northwest trees.

Unsurprisingly, he had a few:

Noble fir: This iconic evergreen, the one Christmas-tree lots charge a premium for, was one Sibley "was really struck with on my first real tree study trip" to the Northwest. The noble Noble ranges throughout the Cascades, mostly south of Seattle. "It has such an elegant shape — each twig looks like a big green broomstick ... And at the top of the tree are these big green or purple cones" decorated with shaggy seed bracts (in the guide, these cones look like well-groomed Dr. Seuss characters).

Western larch: Sibley called this tall and elegant mountain dweller "the tree equivalent of a crane ... They grow very tall, with a straight trunk, usually with just a small group of branches on top." Sibley admires the pale yellow of larch needles in the fall, before they fall off the tree, and the "pale sea green" in the spring when new needles emerge.

Red alder: There are gajillions of alders about — usually the green alder, which colonizes clear-cuts and road cuts and has nitrogen-fixing material in its roots that help restore the soil.

The red alder is its aristocratic cousin. "It is a real tree, a big tree. It usually grows in big stands along rivers and lakeshores. It has delicate foliage and smooth, gray, mottled bark — there's just a suggestion of red in the crown in the winter." And red alders grow in places Sibley associates with good places for birds and birding — wet soils in lowlands along rivers.

I asked Sibley to nominate a nuisance tree, and he took me up on it — the Norway maple. It's a European native, "the starling of the tree world" with big green-purplish leaves. It's escaped the confines of the Eastern U.S. cities it was planted in and is colonizing the Eastern forests. In our area, a native tree like the big-leaf maple has evolved to host a wealth of local insects and animals that feed on it. The Norway maple, "from the perspective of birds and animals, is just a desert," Sibley says.

Sibley moved easily from being a scholar of birds to a scholar of trees: "Just like bird-watching, the trees constantly change appearance, just like the birds change from summer to winter plumage. The trees don't look the same from week to week."

No they don't, and by next week all that lovely red and yellow foliage may be floating facedown in the gutter. So get up, set down the paper or turn off your computer, and take that walk. You'll thank me later.

Mary Ann Gwinn: 206-464-2357 or mgwinn

@seattletimes.com. Mary Ann Gwinn appears on Classical KING-FM's Arts Channel at www.king.org/pages/

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