Hans-Voldemar Trass was born on May 2, 1928, and died on February 14, 2017.
He was an Estonian ecologist and botanist.
Trass has been a member of the Estonian Academy of Sciences since 1975. He was the president of the Estonian Naturalists’ Society in 1964–1973 and 1985–1991.
He was awarded the Acharius Medal in 1992 by the International Association for Lichenology.
He was married to Estonian actress Raine Loo.
They had a son, composer and organist Toomas Trass.
Hans Trass passed away at 88 years old.