Alders are puffing pollen and receiving praise from ecologists

It started back in late winter, with a blush that colored entire hillsides and roadsides.

Alders, among the first to take their cue from the advance of the season, glow with color as their catkins and buds ready for spring. Give the trees a string of warm days, and all heck breaks loose.

Alnus rubra, just now abloom across Puget Sound country, is puffing a fairy dust of chartreuse pollen on the spring breeze. It's the male parts of the tree, for the record, that make all the trouble.

Blame the long catkins festooning alders by the millions, giving entire hillsides a rosy cast. Look closely: The male catkins are crammed with crimson flowers, each packing a pollen punch. Shorter female catkins catch the windblown pollen and form a cone, laden with seeds.

For allergy sufferers, the tree and its pollen can be an annual trial. But ecologists have long appreciated the tree's central role in the lowland forests of Puget Sound.

Alders are the first to do the dirty work of recolonizing forests and stream banks after an avalanche, forest fire, flood or clear-cut.

Alders enrich the soil, grabbing nitrogen from thin air, and fixing it in the soil with the help of organisms on their roots.

Alder snags are pocked with the telltale sign of woodpeckers and other birds drilling for a meal. Some mammals, such as the white-footed vole, may gather as much as 40 percent of their diet just from alder leaves.

Streams lined with alders wriggle with more caddis, stone- and mayfly larvae, feeding on leaf litter. Fish and birds, in turn, feast on the bugs.

Woodworkers also have long prized alder, which readily takes stain or glue and is easy to work.

Yet loggers for generations considered alder a trash tree. "Mighty Doug fir was king, this was this little species that got in there and grew fast and kept big Doug from getting as big as it could. So get rid of it any way you can, spray it, burn it, knock it over, whatever," said David Sweitzer, executive director of the Washington Hardwoods Commission in Camas, Clark County, the tree's chief cheerleader.

Relatively scarce as a commodity because it is mostly harvested incidentally along with Doug fir, in 2000, alder for the first time surpassed Doug fir in price per board foot at the mill. The tree has enjoyed a new appreciation among forest-products pros ever since, even gracing the covers of the major industry-trade publications this spring.

"Never thought I would see the day," Sweitzer said. He of the house with two bookcases, a bench, dining table, sofa table and 7-foot-long work table, all made of alder.

But then, he's not allergic to alder pollen. "I wasn't even aware of the problem."

Lynda V. Mapes: 206-464-2736 or lmapes@seattletimes.com