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53 Chapter 5: Our Forests—Past, Present, and Future

regions that have few roads. Harvesting the timber has a significant impact on the environment and is very costly. Efforts to manage and conserve the resources in the Mexican forests have made a significant impact on the forests in these regions. Today’s forests are impacted by the need to suppress forest fires in many areas. Forest fires, as discussed in chapter four, play an important role in the overall health of a forest. Allowing some to burn naturally can be beneficial. But fires that can harm people or property need to be fought. Fighting fires to protect rural homes and the people who live there can impact the overall health of a forest. Air pollution is also a factor in the health of our forests today. Studies have shown that acid rain and ozone in the lower atmosphere have the greatest immediate impact on the trees and plants in a forested area. Climate change is also impacting our forests today. But the greatest concern is the impact that climate change will have on forests in the future. Forests of the Future If climate change continues in the path that is anticipated, the impact on forests will be significant and varied. Climate change will certainly alter the growth of forests. Climate change is largely the result of increased carbon dioxide in the atmosphere. Carbon dioxide is needed for photosynthesis. This could mean that there forests will be more productive—more carbon dioxide means more photosynthesis, which means more growth. Predictions are that this will be true in areas with fertile soil and plenty of water. However, the increase in carbon dioxide will not have an impact on growth in areas with little water, such as the Southwest desert. Another predicted result of climate change is an increase in the overall global temperature. At first, it might seem that an increase in temperature would extend the growing season for a forest. It could do this, but it could also impact the areas in which some trees will grow. This puts some trees and forests at risk. For example, if the trees that typically grow in the colder regions on top of mountains can’t adapt to increasing temperatures at those altitudes, they will die off. Climate changes will result in more droughts in some areas, and more flooding in others.