Oskar August Henrik Vilhelm Hesselman was born in
Stockholm, Sweden. His parents were factory owner Bror August Hesselman and Marie Louise Hesselman, née Åberg. He was the brother of civil engineer
Jonas Hesselman (1877–1957) and linguist
Bengt Hesselman(1875–1952). Hesselman earned his Ph.D. at
Uppsala University and was an associate professor of botany at Stockholm University. From 1912, he was a professor for forest biology at the Swedish Forest Research Institute (
Statens skogsförsöksanstalt), today the Department of Forest Research at the
Swedish University of Agricultural Sciences at
Uppsala, which he presided from 1925 to 1939. Hesselman was secretary at the Second International Agrogeological Conference in Stockholm in 1910, He was elected a member of the
Royal Swedish Academy of Agriculture in 1913, and of the
Royal Swedish Academy of Sciences in 1928.{{cite web|url= https://sok.riksarkivet.se/sbl/mobil/Artikel/12955 |title = O A Henrik V Hesselman |website= Svenskt biografiskt lexikon ==References==