| Without the forests we would have much less oxygen. One acre of forest provides over 6 tons of oxygen per year! This is because trees (and all green plants) use a process called photosynthesis, during which they take in carbon dioxide and, as a by-product, produce oxygen. Plants "breathe" carbon dioxide, like we breathe oxygen. There has been a balance between species that breathe out carbon dioxide and take in oxygen, and species that take in carbon dioxide and exhale oxygen. Since the 1800's this balance has been upset. Fossil fuels, when burned, create carbon dioxide, so carbon dioxide levels have risen dramatically. Unfortunately, this gas, in large amounts, acts like an insulator and keeps heat near the surface of the Earth. This is called the "greenhouse effect." |
Unlike clouds, "Greenhouse gases", are invisible and build up in the atmosphere. Photo courtesy Naomi Woods. |
| In addition to the other important aspects of the ancient forests, some individual species, such as the yew tree (Taxus brevifolia), have shown great importance in the medical field. The bark of the yew tree provides taxol, an anti-cancer agent. It helps treat ovarian, lung and breast cancer. This property of the yew tree was only discovered in recent years, and if the forests that are home to the yew trees are lost, other medical treatments may also be lost as well. |
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