He completed further studies and served in the military during World War II.
[1] In 1932 Eucalyptus jacobsiana, specimens of which had been collected by Jacobs, was named in his honour by William Blakely.
[2] Following the war Jacobs was appointed as principal and lecturer in silviculture at the Australian Forestry School and remained there for the next fifteen years.
In 1955 The Growth Habits of the Eucalypts was published by the Commonwealth Government Printer, and consolidated much of Jacobs' work.
[1] Jacobs died on 9 October 1979 in Woden Valley Hospital in Canberra.