The number of plantings increased during the late 1970s and continued to do so into the 1980s. From 1977 to 1979 total U.S. production reached about 29 million Christmas trees annually. One species, Scots Pine was planted in numbers which far exceeded demand for the product. As the number of individual farmers increased, better marketing strategies and promotion programs were developed. Helicopters became a fixture on large farms during the early 1980s as growers used them to move trees from the field to the shipping yard. Between 1988 and 1994 U.S. the number of Christmas trees harvested in the U.S. was about 34–36 million per year.