U.S. Forest Service researcher Mark Kubiske examines damage to trees that have been exposed to high levels of ozone.
Scientists are growing trees in a Northern Wisconsin forest – in a bath of greenhouse gasses. There’s a theory that forests can help limit the predicted increase in world temperatures from global warming… and its dire consequences. But early results suggest that Great Lakes forests might struggle to survive the century; doing little to help survival of the planet. The Great Lakes Radio Consortium’s Bob Kelleher has more:
Transcript
Scientists are growing trees in a Northern Wisconsin forest – in
a bath of greenhouse gasses. There’s a theory that forests can help limit
the predicted increase in world temperatures from global warming… and
its dire consequences. But early results suggest that Great Lakes forests
might struggle to survive the century; doing little to help survival of the
planet. The Great Lakes Radio Consortium’s Bob Kelleher has more:
On a research plantation near Rhinelander Wisconsin, some twelve thousand
trees are planted in wide rings. It’s called the Aspen FACE project …for
Free Air Carbon Dioxide Enrichment.
Some trees are growing in high concentrations of carbon dioxide .. a gas
that’s building in the world’s atmosphere, and considered a leading cause
of global warming. Others in elevated ozone … another global warming
pollutant closely associated with auto exhaust.
Dave Karnosky Directs the aspen FACE project from the Michigan
Technological University in Houghton, Michigan.
There’s still debate over carbon dioxide’s role in global warming. But
Karnosky says there’s no denying the upward trend in temperatures, and the
potential consequences.
“Things like glaciers melting on the North Pole, and sea level
increasing; violent storms, increased frequency of violent storms;
increased temperatures which will change the native range of plant
communities and forestry communities.”
There’s more than fifty studies underway here, from Institutions like the
Universities of Illinois and Wisconsin – even the Canadian Forest Service.
The main focus is to find whether forests might absorb significant amounts
of carbon. Holding carbon out of the atmosphere could help keep global
warming from spiraling out of control. If that’s the case, forests could
be used like a sponge to soak up CO2 generated by cars and industries.
But Karnosky’s a forestry expert. He wants to know how elevated carbon and
ozone might affect the region’s trees.
“Will these forests remain as productive in the future? Will
they be more productive, or less? So, we talk about these as being sort of
a window into the future. We like to think of our site as what the future
climate will be, say in the year 2050.”
The research site is eerily reminiscent of the ancient stonehenge ruins in
England.
Each ring is one hundred feet across. The trees are head high, surrounded
by a monument of pipes which rise straight up maybe ten feet higher, and
connect across the tops. A central computer directs high pressure jets of
gas.
Forest Service Biologist Mark Kubiske says early results are surprising.
Trees growing in a high concentration of carbon dioxide do well. Carbon
dioxide is to a plant what oxygen is to an animal. But CO2 isn’t the only
pollutant on the increase. There’s others, like ozone.
In the nearby computer shack, Kubiske says trees grown in ozone pollution
do poorly. Some aspen strains in ozone won’t make it ten years.
“The very sensitive clones are starting to drop out of the experiment; they’re dying
early. And the less sensitive clones are tending to take over the site. So, the effect
of the gasses on the composition of the forests that we’re investigating, is altering the way the different species and the different clones seem to interact.”
Combine ozone and carbon dioxide, and you find that any benefit trees get
from extra CO2 seems to be offset by the damaging effects of ozone.
(ambient sound)
Bill Mattson is a Forest Service entomologist. Mattson says trees grown in
ozone get attacked by insects and fungus at a much higher rate. They also suffer
from animals and birds.
“We’ve noticed that hares and rabbits, for example. They seem to
respond to the smaller plants in a community, and so they start attacking
smaller trees. You’ll see lots of woodpecker injury; lots of sapsucker
injury on those slower growing ozone trees.”
The ozone trees are riddled with small holes from wood boring beetles.
“So if you add those two chemicals together; it somehow is
enhancing the success of the beetles that bore into the stems of these
trees. That was something which I hadn’t expected.”
There’s evidence water moves differently through a tree under the gaseous
conditions. Some trees have elevated tannins in leaves but reductions in
other chemicals. That can have consequences on an ecosystem level, to the
animals and insects that feed on trees.
It might be hard to sustain forestry here in just fifty years. Aspen Face
is a relatively small, controlled experiment; but Mattson says the real
world is a giant experiment with no controls.
“It’s something to be watched very carefully, because we don’t know what the
ultimate consequences will be as we continue to ratchet up
ozone and CO2.”
There’s a dozen similar experiments worldwide. Each treats plants with CO2
and other predicted factors like high temperatures or drought. There’s more
than forestry at stake. There’s a real risk to world food production. If
forests can’t lock up carbon, there may have to be new restrictions on the
sources of carbon … the cars and industries burning fossil fuels.
For the Great Lakes Radio Consortium, I’m Bob Kelleher.