The heavy equipment used in clear-cutting damages soil structure. As total forest acreage continues to decline, so does the capacity of these areas to protect against erosion, clean water and air, and moderate climatic extremes. Tree roots hold soil in place, preventing erosion. Studies show that one acre of trees can clean 16 tons of dust and smoke particles from the air each year. One large tree produces cooling effects equal to ten room-size air conditioners running 20 hours a day, and cuts noise 40 percent.
Trees also absorb carbon dioxide and produce oxygen.
Because tree roots take up water from the soil and tree leaves release water vapor into the atmosphere, trees also play an essential role in the hydrologic cycle -the cycle through which all water on the planet flows.