Cannabis trimming has a long history that dates back centuries. The earliest recorded consumption of cannabis traces back to Asia, where it was used in religious ceremonies and as a medicine. Even back then, cannabis plants were being trimmed by hand to discard excess material that was not needed for those ceremonies or medicinal purposes. From those early days of cannabis through the rise of commercial cultivation in the 20th century, hand trimming became the industry standard practice for preparing flower for sale. Businesses would hire a team of hand trimmers to manually cut and trim the buds to their desired shape and appeal.
Source: Ganjapreneur.com