Sacramento has long been known as the "City of Trees" owing to its abundant urban forest; the first recorded use of the term was in 1855, and it was popular by the early 20th century. It was not always so; it was at first called the “City of Plains” because of the lack of trees, but soon afterwards there were cottonwood trees planted, and eucalyptus varieties were imported in order to dry out swampland. Later, locust trees, and willows were planted along streets, then elms, then palm trees, then fruit trees in the late 1910s. It was the first US city to be designated a City of Trees by the Arbor Day Foundation in 1978.