Trees are one of our most important landscape features. They beautify and enrich our lives throughout the year with their variety of forms, flowers, fruits, seasonal leaf colors, and interesting bark.  They provide oxygen and cooling shade, and they filter out some pollutants from the air.  Trees deflect noise and wind, block unwanted views, and protect the soil from erosion.  They can also reduce rain runoff by capturing and holding rainwater on the leaves and branches before it reaches the ground.  Trees have even been found to have positive psychological effects such as reducing stress, reducing crime rates, and reducing recovery time for hospital patients.  (From the International Society of Arboriculture)