Conserving energy . In very localized ecosystems, strategically placed deciduous trees help cool buildings in summer by providing shade. They also can ease the chill of winter by allowing sunlight to shine directly on them. As few as three large shade trees strategically located around a home can cut the energy bill for air conditioning in half. Moderating Harsh Weather Extremes Trees work as natural barriers to wind, snow, rain, and intense sun in local areas.
Forests also help prevent droughts by maintaining steady stream flows into drier seasons.
Global Biodiversity Many species survive primarily in forests, which in the aggregate provide habitat for perhaps half the forms of life on the planet. A tree stump will serve for many decades as the home of a vast array of wildlife from bears and bobcats to woodpeckers and insects which eventually chew it into an ideal mulch for young saplings. A single fallen dead tree in an ancient forest may shelter as many as 1,500 invertebrates, many of them containing still undiscovered medicinal properties. As habitat for biodiversity, forest ecosystems serve as a critical medium for evolution. Without them, much of life on the plant would be unable to adapt and evolve to new forms.