Natural Wonders: Sage takes heat in home on range
Seattle Times staff reporter
Rugged — and about to bloom yet one more year — it clings to its lofty perch above a rolling sea of pungent sage that stretches to the lolling curves of the Columbia River.
Silvery green year round, sagebrush scents the air with the very essence of the West.
Sagebrush — of which there are several varieties — is the signature of a vast and open landscape: The liquid song of the meadowlark and shy meanderings of the black-tailed jackrabbit are its companions, the open sky and gamboling clouds its Muse.
Sagebrush country, or shrub steppe, once covered more than 200,000 square miles of the West; it was the largest nonforested region in North America. But in Washington, a war against sage arrived with white settlement: About the only thing good homesteaders had to say about sage was that it burned.
"It got off to a bad start," says Bill Rickard, a plant ecologist who has studied the sagebrush landscape of the Columbia Plateau for more than 40 years. "It was, 'Cows won't eat it, horses won't eat it, who needs it?' "
Only recently has shrub steppe been seen for what it is: a place of subtle beauty and brilliant adaptation to arid conditions by plants and animals that survive in a fragile and complex web of interrelationships. Shrub steppe ranges widely throughout the West, in Oregon, Idaho, Wyoming, Utah, Nevada and Washington's Columbia Plateau.
Spring is fat city in sagebrush country. It's when the sage is soft and green with a flush of new growth, called water leaves, brought by spring rain. Twining amid the green are an artist's paint box of blooms: the electric blue of delphinium, the inky purple spires of sulfur lupine, sunny yellow of balsamroot and cotton-candy pink of longleaf phlox.
Standing 4 to even 10 feet high, sagebrush can survive some of the harshest conditions anywhere: subzero cold, and heat of more than 100 degrees; as little as 4 inches of rain a year; and winds that can blast 130 mph.
Washington has lost more of its shrub steppe to development — especially agriculture — than other states because of the presence of rivers used to bring irrigated agriculture to the desert.
What wasn't planted in irrigated crops was plowed for dryland wheat. The biggest, oldest sagebrush was the first to go: It indicated the presence of good soil.
As we buzz by on interstate highways at 70 mph, it may look like there's still lots of sagebrush country left, but only some of it is in good condition. Much has been damaged by livestock; the understory of native grasses and wildflowers is long gone.
Only remnants remain of the real thing: dense thickets of sage sheltering animals that make sagebrush country their home, from the sage sparrow, with its clear song, bright as a trumpeter's reveille, to the black-tailed jackrabbit, with its rocket-booster back legs and gigantic ears that swivel to capture the slightest sound.
Some animals, including the tiny pygmy rabbit, weighing barely a pound, have been pushed nearly to extinction as thick, fragrant stands of sagebrush become more and more rare.
It's the complexity of intact sagebrush country that makes it special: Big sagebrush and other shrubs shelter the delicate forms of wildflowers and green tufts of bunch grasses. The understory is a Lilliputian world of plants, some not even a foot tall, with fanciful names like rosy pussytoes, bastard toad flax, crouching milkvetch and daggerpod.
In between them is a crust on the soil — lichens, mosses, bacteria and algae. Tinted orange, black, green and gray, this crust protects the soil from erosion by wind and water. The algae may also fix nitrogen in the soil, boosting plant nutrition.
This fragile covering, if broken by the hooves of cattle or other intrusions, can take as many as 100 years to reestablish.
Farms at Hanford, abandoned since 1943, still show no sagebrush colonization of ground disturbed by the plow.
Once dominated by perennial, native bunch grasses, Washington's sagebrush steppe is increasingly home to blond mats of cheatgrass, an invasive grass introduced in the 19th century.
One result is conflagrations that incinerate thousands of acres of sagebrush as fire races across carpets of dry cheatgrass. Fire is nothing new to sagebrush, but it didn't used to burn like this; the flames stalled out in bunch grasses, which remained green in summer and grew in clumps with open space in between.
"And every time it burns, it sets back the native plants extensively but doesn't seem to hurt the cheatgrass; they pump out prodigious amounts of seed," said Peter Dunwiddie, director of the research program at the Washington chapter of the Nature Conservancy.
If large swaths are wiped out by fire, regeneration is difficult. Sagebrush spreads by seed, and lacking a "parachute" such as that employed by the dandelion, it can't reseed distant ground. Faster-growing cheatgrass also out-competes sagebrush seedlings.
Built to survive
But sagebrush is no wimp: It is an engineering marvel, built for survival.
When other plants conk out for lack of water, the sagebrush is mining moisture from more than 6 feet down with its deep taproot. Its shallow roots stretch out to more than double the width of the plant.
The plant also can water itself, through a process called nocturnal hydraulic lift: Water is absorbed by roots in the deep, moist soil layer, is transported through the roots to the upper soil layer and released at night, where it is stored for the plant's use the following day.
Tiny hairs cover the surface of sagebrush leaves, giving them a velvety feel, as soft as an earlobe, and a silky sheen. The hairs create an insulating layer of dead air that helps protect the plant from drying heat and winds.
As the temperature climbs, sagebrush will drop about half its leaves to cut down on moisture loss. These ephemeral leaves make carbohydrates, stored in the plant's roots to carry it through the lean times of summer.
Indeed, if left alone, sagebrush is quite durable: Many plants live more than 80 years, and some are truly venerable.
"The overall resiliency, that it can stand these harsh conditions," Rickard said of the sagebrush country, "it's amazing."
Lynda V. Mapes: 206-464-2736 or email@example.com