He received his Master of Arts in Biology from the University of Oxford in 1940 and began to work at the Imperial Forestry Institute (now the Oxford Forestry Institute) in Oxford.
Бренан получил степень магистра искусств в Оксфордском университете в 1940 году и начал работать в "Imperial Forestry Institute" (ныне — "Oxford Forestry Institute") в Оксфорде.