In 2002 it was determined that several English Elms in Cesar Chavez Plaza were hazardous, victims of Dutch Elm Disease. The trees were removed on a Sunday in July 2002. The elms were crafted "into benches, signs and other innovative uses. Also, there will be flags placed on the stump rings, stating what happened at the year of the ring in Sacramento".
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In 2004 an effort to memorialize the trees was undertaken:
"The memorial will largely commemorate the English elm, which many appreciative people consider Sacramento's signature tree. Often exceeding 120 feet in height, its canopy of leaves encompassing entire city blocks, the English elm, and its strapping cousin, the American elm, is a kind of urban sequoia."
An eight inch thick slab from one of the elms of Cesar Chavez Plaza was saved and in turn bronzed by artists Kerry Crutcher & Garr Ugalde. The memorial to the heritage trees of Sacramento features a timeline of city events, from 1885 to 2002, which, in label form, were affixed to the core's surface prior to bronzing. Source
Be sure to check out the web site listed in the variables below. It shows the entire creation process of this memorial.