Trees Under the Influence of Ozone and Co2

  • The circle of trees, as seen from the outside. The white pipe seen near the top delivers either normal air, one, or both of the experimental gasses to the trees. (Photo by Bob Kelleher)

In northern Wisconsin, they’re finding that gasses such as carbon dioxide and ozone will change the makeup of what survives in a future forest. An open air experiment called the Aspen FACE project has been testing trees in elevated levels of ozone and carbon dioxide for ten years. But they don’t know whether the forest can change as quickly as the climate does. The GLRC’s Bob Kelleher has more:

Transcript

In northern Wisconsin, they’re finding that gasses such as carbon dioxide and ozone will
change the makeup of what survives in a future forest. An open air experiment called the
Aspen FACE project has been testing trees in elevated levels of ozone and carbon dioxide
for ten years. But they don’t know whether the forest can change as quickly as the
climate does. The GLRC’s Bob Kelleher reports:


We’re standing inside a circle of trees: paper birch, aspen, and sugar maples, maybe 15
feet high. And they’re surrounded by a ring of large white pipes spraying the trees with
gasses – that’s the high pitched noise.


Among 12 different circles of trees, some get carbon dioxide, or ozone, or a
combination. These are the very gasses believed responsible for changing the climate –
they hold in the earth’s warmth, forcing surface temperatures higher.


Dave Karnosky, with Michigan Technological University, heads the Aspen FACE project,
near Rhinelander, Wisconsin. Karnosky’s trying to predict how these gasses will affect
the northern forest:


“Those species, with aspen and aspen mixed with birch and maple make up a huge
portion of our northern forests, and there was a lot of interest by industry as well as to
what’s going to happen in the future as these greenhouse gasses continue to build up in
the atmosphere.”


Even ten years ago, when this project started, it was clear that carbon dioxide and ozone
levels were on the increase.


Ozone is destructive. It’s bad for people and for plants. Carbon dioxide, on the other
hand, is what we exhale, and what green plants need to grow. Both gasses have been on
the increase, largely due to burning fossil fuels such as in coal-fired power plants and in
cars and trucks. Karnosky says he knew aspen were quite responsive to both CO2 and
ozone:


“We weren’t sure much about the interaction, but we were sure interested in what would
happen with that, because those two pollutants are both increasing at about the same rate
in the atmosphere.”


The Aspen FACE project has shown that most trees grow well when exposed to carbon
dioxide, and most do poorly in ozone. With the gasses combined, bad effects tend to
offset the good ones, but results vary greatly between the different kinds of trees, and
even within a single species of trees, like aspen.


Karnosky has found there’s a tremendous range of genetic variation even among the
relatively few trees they’ve tested. That variation makes clear predictions difficult:


“It’s very tough to make a single prediction for species or individuals within species,
there’s so much genetic variation. So that’s been one of the, I think, kind of the highlights
from what I see in terms of a bit of a surprise for us.”


That genetic variation could be the forest’s salvation. Karnosky thinks that if some
aspens, for example, die off from ozone, maybe others will do okay, and fill the forest
back in. Sugar maples, which seem more tolerant of ozone, could replace some aspen
and birch. Then, the mix of trees in the forest would change, but the forest would
survive.


But, there could be problems if the air changes the forest too quickly. Neil Nelson is a
plant physiologist with the US Forest Service. Nelson says the region’s paper and pulp
industries rely heavily on aspen trees. He’s uncertain how quickly the forest, and forest
industry, can respond if aspen begins to die off – and how long it might take for other
trees to grow in.


“One of my colleagues has said, you know, the key issue may be whether things change
too fast for our society and economy to adjust to, and I think that’s an open question.
There seems to be great plasticity, and we aren’t quite there in terms of predicting from a
forest management standpoint what these results mean.”


It takes time to grow trees, maybe too much time if the climate suddenly shifts. The
Aspen FACE project has already provided regulators preliminary data on ozone. It could
become the basis for future pollution law. But, even ten years into the Aspen Face
project, there’s still a lot more data to harvest among the aspen and hardwoods.


For The GLRC, I’m Bob Kelleher.

Related Links

Outdoor Lab Forecasts Global Warming Effects

  • 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.

Related Links

Marketing “Character Wood”

In an effort that could be replicated across the region, one county in Minnesota is trying to encourage growth of hardwood forests. They think sawmills and related enterprises that use hardwoods will create good long-term jobs. The Great Lakes Radio Consortium’s Stephanie Hemphill has more:

Transcript

In an effort that could be replicated across the region, one county in Minnesota is trying to encourage growth of hardwood forests. They think sawmills and related enterprises that use hardwoods will create good long-term jobs. The Great Lakes Radio Consortium’s Stephanie Hemphill reports:

Forests throughout the Great Lakes are economic powerhouses. In Minnesota alone, the timber industry contributes nearly 8 billion dollars to the economy. Pulp and paper mills dominate the industry in Minnesota. They cut a lot of aspen to produce paper and chipboard. Three fourths of the wood cut in the state goes to these mills. Most of them are owned by big, multi-national companies. Sawmills are much smaller, and they’re usually locally owned. They use a variety of wood, including pine and spruce, maple and oak, to produce paneling, flooring, and trim.

(Car doors slam)

Aitkin County foresters are visiting a logging
site about 50 miles west of Duluth. Most of these trees are about 80 years
old. There’s sugar maple, basswood, and red oak. Such forests provide
prime habitat for a broad range of species. Forester Mark Jacobs says it’s
time to cut some of the trees down, to give others a chance to grow
faster. He wants to do it as much like nature as possible.

“The type of disturbance that would happen in here, since it’s kind of protected from fire, would be individual trees falling. Through mortality or if a windstorm would go through, a small group of trees may fall down in the natural cycle.”

Foresters imitate nature by choosing mainly smaller, diseased or mis-shapen trees to be cut. Joe Jewett has the logging contract to thin the woods. He examines each log to figure out how it can best be marketed.

“The higher grade lumber is around the outside of the log and then here this is the heart, this is the sapwood, and the higher grade is out here.”

The small trees have lots of branches, so the wood will have a lot of knots. So it’s hard to sell, because most people want clear-grained wood.

“Howdy, how’s it going?”

Dan Haugen is visiting Jewett to see if he can help sell the wood Jewett has cut. Haugen is a middleman. He buys wood from loggers and sells it to lumber yards. He’s trying to create a demand for wood with knots and color variations. Haugen calls it “character wood.”

“If you go into most homes, the millwork, the cabinets and the flooring, most of it’s clear. And you can look around in the forest and see all these limbs, and that’s just not how God makes these trees. And so we really need to find some markets for character grades of forest products.”

(Saw, sfx from processor)

Aitkin Hardwoods buys some of Haugen’s wood. The small factory is filled with the smell of freshly cut boards. Stacks of lumber reach to the ceiling. The oak, maple, ash, and aspen boards will become paneling, flooring, and trim. Manager Rich Peterson says he’s found a market for character grade lumber. He says people building lake cabins in the area want informal-looking wood to build their casual second homes. They find clear wood too boring.

“They haven’t seen any mineral streak, there are
no knots, and all of those things today are considered beautiful.”

Peterson employs four workers and sells about 40 semi-loads of lumber each year. He’s expecting his business to grow. He says Aitkin County’s long-term approach to forest management will eventually produce more, and better quality lumber. Some day, he hopes furniture could be produced here. That would bring more jobs, and better profits than paneling and flooring.

Hardwood manufacturing in Aitkin County is growing slowly. The raw materials are growing slowly in the woods, and entrepreneurs like Rich Peterson are slowly building markets. It’s a different scale from the pulp mills that employ hundreds of people and cut down thousands of acres of trees every year. And that’s fine with Aitkin County’s land department. Forester Mark Jacobs says the local economy will still benefit from a growing hardwood industry –slowly but surely.

“Some smaller sawmills expanding, maybe a kiln-drying facility, maybe some secondary manufacturing, and in total it could be several hundred employees.”

And Jacobs says in the meantime, people who live in the county, and people who have cabins here, enjoy the hardwood forests.

For the Great Lakes Radio Consortium, I’m Stephanie Hemphill.