From the Seattle Times:
http://seattletimes.com/html/localnews/2019878659_oldtrees11m.html
Loss of ancient, big trees becoming a global issue
KEN LAMBERT / THE SEATTLE TIMES
A man visits an old-growth cedar during a
walk
along the border of North Cascades National Park.
The Pacific
Northwest was once covered
with such huge trees.
Big trees are vanishing around the world and often are not
being replaced. The loss of these trees can be devastating to other
species.
Seattle Times science reporter
It's not news to Northwesterners that most of the giant firs and cedars that
once dominated the region's forests are long gone, felled by decades of
logging.
But a review of ecosystems around the world finds that big trees are
vanishing almost everywhere — and aren't being replaced.
"What we're seeing is a global phenomenon," said ecologist David Lindenmayer
of Australian National University, lead author of a paper published in
the Dec. 7 edition of the journal Science. "There are different sets of drivers — it
might be fire, logging, drought, disease — but they all lead to basically the
same outcome."
The loss of big, old trees can be devastating to thousands of other species
that nest and take shelter in their branches and cavities, said University of
Washington forestry professor Jerry Franklin, a co-author of the
paper.
In some forests, nearly a third of all birds, reptiles, mammals or marsupials
make their homes in ancient trees, the scientists reported. Gnarled, old trees
also produce a bounty of seeds to replenish the forests and are a vital source
of food.
"These big, old trees are really important elements of many forests and many
landscapes," said Franklin, who was a key player in the 1990s-era battle to
protect the remnants of the Pacific Northwest's famed old-growth forests. "An
old tree tends to be very idiosyncratic, just like we are as human
beings."
Though the causes for the decline are diverse, all involve the common
denominator of human intervention.
In Scandinavia, logging companies are simply targeting the biggest, oldest
trees, the researchers found.
On the savannas of Northern Australia, nonnative grasses planted to improve
cattle and sheep grazing burn seven times hotter than native grass, decimating
trees that weathered centuries of normal fire.
If the rate of loss doesn't abate, all of the trees in the region — both old
and young — will be gone in 50 years, Lindenmayer said.
In Brazil, where rain forests have been reduced to fragments, old trees are
much more vulnerable to being toppled by wind and parasitized by strangler vines
that proliferate after logging.
Many forest ecosystems are so altered by invasive species, human management
and shifting climate that young trees no longer are able to grow into behemoths,
the scientists said.
Infestations of a plant called lantana smother seedlings in some parts of
India, Lindenmayer said.
In the mountain-ash forests of Southern Australia, where he's worked for
nearly three decades, cycles of fire followed by salvage logging prevent forests
from maturing.
Shifting mindset
Forestry experts have long been aware of the decline of big trees, said
Oregon State University professor Mark Harmon, who was not involved in the
analysis.
But the Science paper is one of the first attempts to pull together evidence
from different parts of the world and make the argument that big trees deserve
special consideration.
"Maybe it will change the mindset," Harmon said.
Lindenmayer got interested in big trees while tracking the fate of
Australia's equivalent of the northern spotted owl: the Leadbeater's possum, a
4-inch, big-eyed marsupial that can only nest in ash trees at least 200 years
old.
Unless the country takes steps to protect the ancient ash trees, the world's
tallest flowering plants, the possum is headed for extinction, he
said.
In the Pacific Northwest, legal wrangling over the old-growth-dependent owl
led the federal government to restrict logging on millions of acres of federal
forest in Washington and Oregon. During the debate, Franklin proposed a more
eco-friendly alternative to clearcutting that leaves some trees
standing.
No policy
But there's still no nationwide policy that singles out big, old trees for
protection or works to ensure that young trees are able to replace their elders,
he said.
"We're dramatically reducing the number of big trees," Franklin said. "As
part of our active management, we need to be planning to restore historic levels
of those big, old trees."
The scientists compared the decline of ancient trees to the decimation of
tigers, whales and other large mammals. After decades of protection, many
slow-growing species like the blue whale are still hovering on the brink of
extinction, Lindenmayer pointed out.
"The stakes are very high," he said. "Big trees can be lost very quickly, but
it can take centuries for them to be replaced."
Sandi Doughton: 206-464-2491 or sdoughton@seattletimes.com
