Mark Kubiske checks the valve that controls the flow of greenhouse gases to a stand of sugar maples, birch and aspen. (Photo by Jennifer Simonson)
Scientists from around the world are studying how higher levels of carbon dioxide will affect forests 100 years from now. They’re doing that by pumping higher levels of CO2 and ozone into stands of trees. The Great Lakes Radio Consortium’s Mike Simonson visited the experimental forests and has this story:
Transcript
Scientists from around the world are studying how higher levels of carbon dioxide will affect forests 100 years from now. They’re doing that by pumping higher levels of CO2 and ozone into stands of trees. The Great Lakes Radio Consortium’s Mike Simonson visited the experimental forests and has this story:
(sound of “quiet area”)
The north woods of the Great Lakes states are stands of millions of acres of pine, maple, birch, and aspen forests. It’s a perfect place to try to figure out how trees will react to the higher levels of ozone and carbon dioxide scientists expect in the future.
(sound of beeping fence gate)
The first thing you notice at Aspen Free Air Carbon Dioxide Enrichment Project – Aspen FACE for short – is two huge tanks inside the fenced in enclosure. Each one is bigger than an 18-wheel tanker truck. They’re full of carbon dioxide… CO2. So much CO2 is used in this experiment, the tanks are filled twice a day.
(sound of filling tanks)
If you looked at the site from an airplane, you’d see 12 circular tree stands surrounded by 30 foot high pipes. Those pipes pour CO2 or ozone gases or both into the air surrounding birch, sugar maple, and aspen trees. The scientists know that greenhouse gases in the earth’s atmosphere have been increasing. They believe two centuries of industrial pollution has contributed to the problem. And they expect the CO2 and ozone levels to double by the end of this century. They’re raising the level of greenhouse gasses in different mixes to see what the predicted levels will do to forests.
This open air project is different than previous experiments. David Karnosky is with Michigan Tech. He’s the Project Manager for Aspen FACE. He says before these kinds of projects, they just tested trees inside places like greenhouses.
“We needed to get out of those chambers. We needed to have a more realistic, real world sort of situation where we had multiple trees. We wanted real intact forest communities. We didn’t want to have just a small number of trees inside of a chamber.”
The United States Department of Energy launched this experiment in Wisconsin’s northwoods seven years ago. Karnosky says they’re learning how the trees react to the higher CO2 levels, and that could shape the future of the world’s timber industry.
“Who will be the winners? Who will be the losers? Will aspen or birch or sugar maple? In northern Wisconsin here we’ve got probably 40 million acres of those species mixes. What’s going to happen under elevated CO2 in the next 100 years? Will these forests remain as they are?”
(sound of driving on gravel)
Driving to one of the experimental circles, we pull up to a ring of trees. Mark Kubiske is one of the two full-time on-site researchers.
“Now this particular ring is an elevated CO2 plot. CO2 is delivered through this copper pipe. It runs to that fan, there’s a large fan right on the end of that gray building.”
The scientists have found that trees in the CO2 circles grow 30 percent faster than trees without the gas.
“The trees are larger in diameter, they’re straight, they have lots of leaf area, they just look very healthy. That is just in tremendous contrast to the ozone ring. We’ll go up around the corner and look at one.”
Nearby another circle of trees is not doing nearly as well. The trees are skinny, twisted not as tall as the other sites. Higher ozone levels are hurting the trees.
At the sites where pipes emit both ozone and CO2, the tree growth seems normal – except for some stunted maple trees. The leaves of the aspen and birch take in much of the CO2, convert it to sugar which goes to its roots, eventually becoming a natural part of the soil. That suggests forests may help alleviate gases that cause global warming. The Project Director, David Karnosky says CO2 and ozone appear to cancel each other out. But he says it’s too early to draw any firm conclusions. Ultimately, he says governments will be able to look at this glimpse into the future and try to come up with emissions policies that help.
“The whole issue of the Kyoto protocol, our government not signing off on that. There’s been some relaxing of the feelings from what I’ve seen from the President’s report now that they’re beginning to realize that elevated CO2 is having an impact on global warming and could be impacting our plant communities.”
Karnosky says it’s possible that besides reducing emissions, governments might determine that planting more trees might be very helpful in reducing greenhouse gasses worldwide.
For the Great Lakes Radio Consortium, I’m Mike Simonson.