"The primary purpose of the Legislature in establishing "Arbor Day," was to develop and stimulate in the children of the Commonwealth a love and reverence for Nature as revealed in trees and shrubs and flowers. In the language of the statute, "to encourage the planting, protection and preservation of trees and shrubs" was believed to be the most effectual way in which to lead our children to love Nature and reverence Nature's God, and to see the uses to which these natural objects may be put in making our school grounds more healthful and at-tractive."