Burret had a greater interest in natural science than in law, and he eventually abandoned his law studies to conduct botanical research in Berlin, where he earned a Ph.D. in 1909 for his taxonomic thesis, and quickly became one of Germany's most prominent botanists.
Burret made numerous travels in Europe and Africa, as well as South America.
He was invited by the Brazilian government to make a trip to that country, specifically for the study of the various species of palm trees indigenous to the region.
Shortly after his return to Germany, he voyaged to the Old World tropics, visiting Sri Lanka, the Malay Peninsula, Java, and Sumatra in 1938 and 1939.
Burret was among the first botanists to conduct ground-breaking research on palms, beginning in Africa and later in South America and Indomalaysia.