It was estimated that more than a million trees were planted in Nebraska on the first Arbor Day. During the 1870s, other states passed legislation to observe Arbor Day, and the concept has since spread to many countries around the world. Trees provide wildlife habitat for birds, mammals and reptiles. The hairy leaf surfaces of trees trap and filter out ash, dust and pollen particles carried in the air. Trees lessen the impact of raindrops on the soil surface and help keep sediment from washing into rivers and streams.
Trees beautify urban and community areas, such as parks, streets and school yards.
The hair-like root fibers of trees help filter groundwater, trapping nutrients and pollutants that could contaminate it.