Weyerhaeuser begins thinning the trees it planted after Mount St. Helens eruption

To mark the 25th anniversary of the Mount St. Helens eruption, May 18, 1980, Daily Astorian reporter Kate Ramsayer took a helicopter ride to look over the volcano and the considerably changed landscape around it.

MOUNT ST. HELENS, Wash. - There are obvious risks inherent in operating a tree farm on the slopes and valleys surrounding an active volcano.

When Mount St. Helens erupted, 25 years ago today, the blast leveled almost 150,000 acres of forest lands, in some places up to 17 miles away. Weyerhaeuser, the largest private landowner in the area, lost 68,000 acres of its land, much of it mature trees ready to harvest.

But two decades after a massive reforestation project, the timber company is now starting its first round of thinning of the Douglas firs and other trees that were replanted in the blast zone.

In 1980, Dick Ford was Weyerhaeuser's district forester for the Mount St. Helens tree farm.

"A lot of what we had that was ripe for harvest was up in this area," he said recently, standing in the Forest Learning Center that is located within the blast zone. The center, which Ford directs, is operated by Weyerhaeuser as well as the Washington State Department of Transportation and the Rocky Mountain Elk Foundation. It is designed to give visitors information about the local ecosystem, how the company is managing the lands, and the salvage and reforestation efforts that took place after the eruption.

KATE RAMSAYER - The Daily Astorian

Weyerhaeuser is conducting the first thinning operation of forests replanted after the eruption of Mount St. Helens. The area above was one of the first to be thinned. Foresters are reducing the number of trees per acre from 400 to 180 to allow the healthiest trees to thrive, Weyerhaeuser's Dick Ford said.Foresters worked for 18 months salvaging what timber they could, taking ash-covered trees from about a third of the forests that were flattened. In all, about 850 million board feet of timber was recovered.

The question then became whether the company should replant in ground layered with ash. It was a difficult decision, Weyerhaeuser spokeswoman Jackie Lang said, but the foresters took on the reforestation project as a challenge.

"My district was gone, so I might as well replant what was destroyed," Ford said. Forest ownership is rife with risks from many events, like fires, windstorms and disease, and the threat of another eruption "isn't any more concerning than all the other natural disasters that can occur," Ford said.

So the company handplanted its land around St. Helens with 18 million seedlings.

Foresters had done a test plot to see how well trees grew in the ash one month after the mountain blew, Ford said, and found that the ash didn't have many nutrients. That meant that trees probably wouldn't grow if they were planted in that layer.

Dick Ford"The only way we were going to get the growth and health that we want is to plant in soil," said Ford, who was in charge of the company's reforestation efforts.

The planters dug holes through as much as 10 inches of ash to put seedlings in soil, quickly learning tricks to identify where the ash was shallowest, including on the north side of stumps or where plants were still poking through.

The replanting took seven years, and was slowed in part because the company simply didn't have the seedling inventory for such a major effort. The majority of the trees planted were Douglas Fir, with 7 million noble firs, 50,000 lodgepole pines and 182,000 black cottonwood trees as well.

While the timber company replanted most of its land, it also gave 17,000 acres to the federal government in a land trade, on which the government set up Johnston Ridge Observatory, Coldwater Ridge Visitor Center and other areas of the Mount St. Helens National Volcanic Monument. Because the government left the flattened forest lands as they were, it provided an opportunity to study natural forest regeneration, Ford said.

"Now you have a really neat comparison of how forest management can work and how nature can work," he said. What foresters find, he added, is that management speeds up the growth of the forest and creates more uniform density.

KATE RAMSAYER - The Daily Astorian

Coldwater Lake sits quietly a few miles from the crater of Mount St. Helens. The lake was formed when streams were dammed up as a result of the volcano's eruption and landslides.Two and a half decades later, the boundary between the replanted lands and the area left to grow naturally is obvious from the air, with green trees on one side and on the other, smaller trees and places with downed logs still pointing away from the volcano.

The planted trees have even been helped along by the ash, Lang said, since it prevented weeds from springing up and held in the moisture.

With some of the replanted trees now at 70 feet tall and overcrowding their neighbors, Weyerhaeuser started its first thinning harvests in February.

Thinning allows the company to weed out trees that wouldn't make good lumber, and gives the trees with the most potential more room to grow, Ford said.

Thinning technology has improved since 1980, and foresters can now select which trees to thin and remove the trees without damaging the ones left standing or the forest floor. The harvesting machines remove branches and leave them on the ground, which returns nutrients to the soil.

The company plans to thin the entire replanted blast zone of 27,000 acres over the next 10 years. Once the forests reach maturity at 50 to 60 years old, they will be clear cut and replanted again.

For now, the company is hosting a commemoration event today at the Forest Learning Center, and anticipating one of its busiest summers at the center since it opened in 1995, because of last fall's activity on the mountain.

"It's renewed the interest, brought it back to life," Ford said.