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PRI's Environmental News Magazine

Fatal Pine Needle Disease: A U.S. Concern

Air Date: Week of March 14, 1997

An outbreak of forest disease is causing concern in the Pacific Northwest where the fungus called Swiss Needlecast is beginning to infect the nation's most highly productive forests. Ley Garnett reports from Portland, Oregon on the disease without a remedy.

Transcript

CURWOOD: It's Living on Earth. I'm Steve Curwood. The fungus called Swiss Needlecast was first discovered early this century in Switzerland on Douglass fir trees imported from the Pacific Northwest. And now there is concern in the Pacific Northwest itself about the spread of this deadly blight. While it has hampered US Christmas tree growers the past 2 decades, the disease is now beginning to affect many trees in the nation's most highly productive forests. And as Ley Garnett reports, scientists don't yet have a remedy.

(Footfalls)

GARNETT: In the Columbia River Valley near Cathlamet, Washington, 3 foresters from Willamette Industries, a large Northwest timber company, walk through the woods inspecting trees.

JOHNSON: This tree here's just a classic Swiss Needlecast tree. All the lower limbs are barren, and as you go up to the top where you'd expect to see a full crown, all you see are last year's needles.

GARNETT: This grove ranges from 25 to 40 years old and has a mix of trees dominated by Douglas fir. Most of the Douglas fir have thick, green, healthy branches. But others are almost like skeletons, with only a few needles on every branch. Greg Johnson, a forest biologist for Willamette, uses a magnifying glass to check for black dots on the needles, one sign of Swiss Needlecast. He says the disease, a type of fungus, damages trees by smothering them.

JOHNSON: So, in the heavily infected needle, the needle can't breathe because it's all stuffed up. It's got a bad cold.

GARNETT: Eventually, these needles fall to the ground prematurely. Without them, trees aren't able to photosynthesize sugars needed for normal growth.

(A ratcheting tool)

GARNETT: Using a device that looks like a modified lug wrench, Willamette company timber manager Tom Holt drills a small hole in the trunk of an infected Douglas fir and pulls out a core sample the size of a thick pencil. The tree rings are tightly packed, a sign the fir isn't growing as fast as it should.

HOLT: Telltale pop of the metal.

(Ratcheting sounds continue)

HOLT: This when you get a significant decrease in the growth, very dramatic.

GARNETT: Swiss Needlecast spreads through spores, and moisture facilitates dispersal. Rain, or even foggy air, helps them move from branch to branch and tree to tree. Unusually heavy rain in the Northwest over the last few years is thought to have triggered the outbreak. While the disease can be controlled with fungicides, widespread spraying would be too expensive and would endanger the area's many streams and rivers. For timber companies the key question is whether to cut the sick trees and replant. Again, forester Greg Johnson.

JOHNSON: One of the challenges is to determine when you've suffered enough, and (laughs) a stand like this has pretty obvious visual symptoms but we're still getting growth here. And it may be the best thing to do economically may be to hold onto it, let it grow some more.

(Traffic sounds)

GARNETT: Outside the offices of the Oregon State Forestry Department in Salem, a massive stump of a 600-year-old tree, 10 feet in diameter, rests on a pedestal. It's a monument to the Douglas fir, Oregon's official state tree. The Douglas fir is the most important tree in North America to the timber industry, and it has made Oregon the nation's leading producer of wood products. Never before have the coastal fir forests of the Northwest faced such a potentially serious threat from a contagious disease. Inside his forestry office, state tree pathologist Alan Kanaskie leads Oregon's battle against Swiss Needlecast. He says the recent spread of the disease is a mystery.

KANASKIE: We've known about it for a long time. It's been fairly well studied. However, it's never reached these kinds of levels in a native Douglas fir forest before.

GARNETT: Mr. Kanaskie suspects that Needlecast thrives on Douglas fir trees planted from non-native commercial seed stocks that haven't developed immunity to the disease.

KANASKIE: It's like when we travel to a foreign country, we're not quite adapted to all the different diseases and things that occur there, so we're susceptible. And that's kind of what's happening with the Douglas fir from a genetic standpoint, is that kind of movement.

GARNETT: State foresters are pushing hard to unravel this mystery and halt what they say could be a devastating blow to the northwest timber economy. So far 130,000 acres of Douglas fir forest have been stricken in Oregon alone. But foresters suspect new surveys will show the infestation has spread even further. Environmentalist Chuck Willer, who heads the Coastal Range Association, calls Swiss Needlecast nature's response to industrial over-management of forests. He runs through a long list of examples.

WILLER: Genetic seedling selection, nitrogen fertilization, all kinds of site prep activities, an astronomical amount of herbicides and other chemicals put on the ground. We feel that perhaps natural processes are being circumvented or ignored in an attempt to maximize the fiber output from the land.

GARNETT: Mr. Willer and other environmentalists support efforts to stop the spread of the disease as long as the solution does not call for more logging. At this stage there are more questions than answers about Swiss Needlecast. Greg Filip, a forestry professor at Oregon State University, says he thinks to stop the spread of Swiss Needlecast the region may have to move away from its most prized timber source.

FILIP: And until we are able to pinpoint the types, the genetic stock that is more resistant and we can actually use those for planting, I think the safest thing right now if someone is planting is to actually use some other species besides Douglas fir.

GARNETT: For now, state and Federal agencies and several timber companies have formed a Swiss Needlecast Research Cooperative. The co-op is eagerly awaiting results from a new aerial survey extending from northern Washington to Oregon's border with California. The survey should disclose how fast Swiss Needlecast is spreading, and whether it's about to reach large inland commercial forests of Douglas fir located near the Cascade Mountains in Washington and Oregon. For Living on Earth, I'm Ley Garnett in Portland, Oregon.

 

 

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