Monday, Dec 21st, 2009
Scientists from the University of Wisconsin-Madison and the University of Minnesota at Morris have found that increased levels of atmospheric carbon dioxide have led to the rapid growth of certain tree species. The quaking aspen, a popular North America deciduous tree, has seen a 50 percent acceleration in growth over the past 50 years due to increased CO2 levels.
Trees are necessary climate regulators since they process carbon dioxide and give off oxygen. Humans process oxygen and give off carbon dioxide, working harmoniously with natural plant life to maintain proper atmospheric composition. Since natural forests represent about 30 percent of the earth’s surface, they are highly effective at segregating greenhouse gases.
The quaking aspen is a vibrant, dominant tree found in both Canada and the United States. It is considered to be a “foundation species”, meaning that it helps dictate the dynamics of the plant and animal communities that surround it. Roughly 42 million acres in Canada and 6.5 million acres in Wisconsin and Minnesota are composed of aspen trees.
Elevated levels of CO2 will naturally lead to increased plant growth since CO2 is a precursor to plant food. Tree-ring analyses verified that aspen trees have been growing at an increasingly accelerated pace over the years because of this phenomenon.
Because accelerated growth was not seen in other tree species like oak and pine, scientists admit they will have to further investigate the issue. Similarly, drier regions where the trees were found did not experience the same rapid growth rates as those found in the wetter regions.
An interesting side effect of increased carbon emissions by human activity is that plants will grow more quickly. CO2 is to plants as oxygen is to humans, so the more CO2 is in the atmosphere, the more quickly many plants can grow.
Of course, plants produce oxygen as the “waste” product of their respiration, and that’s a poison to other plants, so there’s a natural balancing effect that keeps oxygen and CO2 levels in balance over the long haul.
This is why greenhouse gases are called “greenhouse gases”, by the way — because they turn the planet into a really effective greenhouse where plants grow like crazy. Of course, the clear-cutting of rainforest in the Amazon (and elsewhere) kills any chance of those regions taking part in that accelerated plant growth. Even in a high-CO2 environment, human beings can destroy plant life with bulldozers.
It’s interesting that plants and humans breathe the same air but extract very different chemical elements from it: Humans need oxygen while plants need carbon dioxide. For both species to survive, the air needs to contain both chemicals in balance. Currently, the oxygen content of the air is roughly around 20% (and falling).
This article was posted: Monday, December 21, 2009 at 4:05 am