This is the lead in The Guardian’s article entitled “Arkansas: tree honoring 1919 Elaine Massacre victims cut down”:
The willow was planted in April in remembrance of the victims of the massacre, one of the largest racial mass killings in US history.
It occurred during the summer of 1919, when hundreds of African Americans died across the country, at the hands of white mob violence during what came to be known as the “Red Summer”.
If you don’t know about this massacre, The Washington Post provides more historical details in its article entitled “A massacre of blacks haunted this Arkansas city. Then a memorial tree was cut down” (https://www.washingtonpost.com/history/2019/08/30/massacre-blacks-haunted-this-arkansas-city-then-someone-cut-down-memorial-tree/). Here’s a quote that summarizes the extent of the massacre.
For days, mobs of white men killed at least 200 black people, with assistance from about 500 troops called on by Arkansas Gov. Charles Brough. Some scholars estimate the number to be closer to 800 killed.