National Arbor Day is currently celebrated on the last Friday of April in most U.S. states. Alabama considers the last full week of February to be Arbor Day. This is due to matching the date with the best times to plant a tree, a customary Arbor Day activity.
The first Arbor Day was held in 1805 in Villaneuva de la Sierra in Spain to celebrate the importance of trees and nature. The first Arbor Day in the United States was held on April 10, 1872 in Nebraska. On April 15, 1907, President Theodore Roosevelt issued an "Arbor Day Proclamation to the School Children of the United States". Arbor Day has therefore been considered an April holiday. Like the United States, many countries have days similar to Arbor Day but they are known by different names and fall on different dates (list per Wikipedia).
Image: Burton Public Library
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Text ed: NF