Why are trees so vital to our lives? They prevent erosion, provide oxygen-rich air, and they give shade from the hot sun. These are just a few of the many reasons. They’re also the reasons why we celebrate Arbor Day. Arbor Day was started in April 1872 by J. Sterling Morton. Morton, a pioneer of the Nebraska Territory and a tree enthusiast, praised the benefits of trees and encouraged his fellow pioneers to plant them across the then dusty and treeless Nebraska landscape. He even went so far as to propose a tree-planting day to the State Board of Agriculture.