Poplars take root in second year


When asked if he ever thought he'd be managing trees, Patrick Wiltzius, wastewater superintendent for the city of Chehalis, laughed.

"No. But I keep up on the newest thing in the industry and this is one of those," Wiltzius said, pointing toward the grove of small poplar trees.

About 46,000 poplars were planted last summer on about 190 acres of what was once known as the Hamilton property. Nine varieties are spread into 11 management units ranging in size from 9.5 to 31 acres. Modeled after a 90-acre farm in Woodburn, Ore., the area is part of Chehalis' new wastewater treatment plant. Faced with increasing pressure to end the practice of releasing treated wastewater into the Chehalis River, the city decided to plant a farm of poplar trees to soak up what is called Class 1 reclaimed water.

"For reclaimed water, we're probably one of the biggest in the Pacific Northwest, or will be once we get going," Wiltzius said.

Poplars are used both for pulp and lumber. Chehalis decided to plant its poplars to be used for saw logs. Chehalis is also studying the possibility of planting hay on about 80 acres, such as the more sensitive areas, as well as a few spots too wet for poplars. Both products would be harvested and the profits would benefit the wastewater program.

"We won't make a bunch of money off this but it will help offset the costs of treatment," Wiltzius said.

When the poplars were planted last summer, they were no more than twigs. This year they range between 2 feet and 14 feet tall. Each of the 11 management units are connected to 17,500 feet of underground irrigation pipes. The city plans to bore under the Chehalis River next year to lay the pipe that will connect the farm to the new wastewater treatment plant being built on the west side of Interstate 5. Until they begin receiving reclaimed wastewater from the plant in about 2008, there is no irrigation other than natural rainfall watering them.

"Once we start irrigating them, we're told, they'll really take off," Wiltzius said. "These have been a couple of pretty dry summers and they've done fine."

When they're ready to harvest, Wiltzius said, the poplars will stand about 120 feet high.

With the help of tree expert Dr. Jon Johnson of Washington State University, officials chose varieties best suited for the land as well as ones with large leaves. Reclaimed water, which is not considered quite clean enough for human consumption, is absorbed by the trees and evaporated out through the leaves to come back down as rain and recharge groundwater.

"We're not treating water here, we're evaporating it," Wiltzius said. "We believe this is one of the best options for Chehalis to dispose of the affluent."

It takes about three half-time staff members working to keep the farm running, especially during growing seasons. Until recently, the trees were too immature for the use of pesticides and herbicides so weeds had to be pulled by hand or, where possible, by tractor.

"Once they get about five years old, the trees will form a canopy that will shade out any weeds," Wiltzius said.

It is estimated the poplar farm will be able to handle a peak flow of more than 3 million gallons of reclaimed water per day. Wiltzius said the city currently creates about 1 million gallons at peak times. But another possibility that excites city officials is the possible uses of the reclaimed water other than watering poplar trees. The non-potable water is used by nearby jurisdictions for purposes such as watering parks and city right of way and for industrial steam plants.

"This provides a reclaimed water infrastructure so if someone in the industrial park wanted reclaimed water instead of potable water, they could do that," Wiltzius said of the poplar farm.

The other new addition to the poplar tree farm is five monitoring wells required by the Department of Ecology that recently began collecting data on the groundwater at the site. Wiltzius said Chehalis needs to study the current quality of groundwater there and be able to compare it to the water once the treatment plant is up and running

"The only issue we could have is if we somehow pollute the groundwater so that's why we're working to establish a baseline of what it is from past use," Wiltzius said.

Carrina Stanton covers municipal government and health for The Chronicle. She may be reached at 807-8241, or by e-mail at cstanton@chronline.com.