Rain forest report leaks with omissions
By David L. Peterson
Peninsula Daily News
Tuesday, March 5, 2002
Imagine yourself standing in a towering conifer forest a few miles from the Pacific Ocean on the North Olympic Peninsula.
The fog swarms around you as you look around to observe the high canopy draped with mosses and lichens.
A Roosevelt elk raises its head to watch you as a winter wren sings in the distance.
The scene is the famed Olympic rain forest.
We know that similar forests have existed for the last 60,000 years or so because data from tree pollen accumulated in bog and lake sediment tells us so.
Tree specimens such as Sitka, spruce, and western hemlock have been a part of the Western Washington landscape for at least 60 millennia through all kinds of climates.
Now a World Wildlife Fund (WWF) report tells us these forests will disappear due to global warming (Feb. 10 PDN Sunday Showcase, “Are our rain forests...drying up?”)
A a scientist who has spent years of studying the biography of the North Olympic Peninsula, including a decade of research on the effects of climate change on forests of this region, I find this prediction does not match the scientific data and it unduly alarmist.
In their report, the WWF assumed that tree species will migrate only northward, when in fact there are many habitats at different elevations and topography positions where species can readily grow in a warmer climate.
They used computer-simulated models intended for general estimates of vegetation change at the continental-to-global scale, not the smaller scales.
By extracting a tiny piece of data out of context without any other supporting evidence, they inferred that the Olympic rain forest ecosystem will
vanish in a warmer climate.
Here is what the scientists say:
* The same species combination---cedar, spruce, hemlock, Douglas fir---exists at several locations in the western Cascade Range, in some cases with only half as much rainfall as on the western Olympic Peninsula.
* A huge deduction in rainfall would be necessary to change the structure and function of this system.
None of the models used to predict future climate indicates that rainfall will decrease measurably; in fact, most predict a slight increase for the Pacific Northwest.
In addition, recent evidence suggests that the growth rate of tree species at some coastal locations has been increasing since the early 20th century.
We do not know if this is due to increased temperature, increased atmospheric carbon dioxide or another factor. But a growth increase does not suggest an ecosystem in decline.
* Scientific data indicates that large areas of the North Olympic Peninsula have been burned by wildfires over the past several hundred years.
Although rare (approximately every 300-600 years) those fires are naturally occurring events.
Large windstorms also can cut out wide swaths through mature forest (e.g....the famous “21 Blow” of 1921).
If a warmer climate is accompanied by more frequent wildfires or more windstorms, the effects of these disturbances would be much greater than a small temperature increase.
Of course, a century of logging has had the biggest impact of all.
* Scientific data shows that the biggest effects of climate change will likely occur in Pacific Northwest forests at high elevations.
During the past century, sub-alpine meadows have been filling in with trees in many locations, largely the effect of periods of reduced snowpack.
The WWF ignored this information, choosing instead to use information out of context that supports a good story in the media.
Selective use of scientific information is a disservice to the entire scientific community.
Largely unfounded predictions may do more harm than good, particularly when such predictions do not come to pass.
At worst, this gives naysayers another excuse to say, “See there really isn’t a problem.”
Rest easy. The Olympic rain forest will likely be around for many generations to come.
(David Peterson is a research scientist with the U.S. Forest Service Pacific Northwest Research Station in Seattle.)
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