Complex sentence: When he visited Buddhist monks in Nagasaki in February 1691, he was the first western scientist to describe the tree "Ginkgo biloba"-scientists at the time thought that all Ginkgo species were extinct.
Split into simpler sentences: When he visited Buddhist monks in Nagasaki in February 1691, he was the first western scientist to describe the tree "Ginkgo biloba". Scientists at the time thought that all Ginkgo species were extinct.