During the years between 1867-1882, Morton dropped out of politics in order to spend more time promoting agriculture. He served on the Nebraska State Board of Agriculture and was a member of the state’s Horticultural Society, advocating improved farming methods, conservation programs, and tree planting.
In 1872 the Nebraska State Board of Agriculture adopted Morton’s resolution to create Arbor Day, a day set aside to plant trees. Prizes were offered to counties and individuals for planting properly the largest number of trees on that day. It was estimated that more than one million trees were planted in Nebraska on the first Arbor Day.
Nebraska celebrates Arbor Day on the last Friday of April. All 50 states celebrate this holiday, although the dates may vary to match each local climate’s best time to plant trees.