Smudge Pot

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I remember years ago visiting citus groves near Alta Loma CA in the winter and they were using smudge pots and I went out and saw them in action -- quite fascinating how the heat and the smoke caused the frost to retreat.
In my research I believe that this particular smudge pot is a single louvered stack above a fuel oil-filled base. In my other vid you will see a taller version known as
A smudge pot (also known as a choofa or orchard heater) is an oil-burning device used to prevent frost on fruit trees. Usually a smudge pot has a large round base with a chimney coming out of the middle of the base. The smudge pot is placed between trees in an orchard. The burning oil creates some heat, but more importantly, a large amount of smoke, particulates, carbon dioxide, and water vapor. This deliberate smog forms a "blanket" that blocks infrared light, thereby preventing radiative cooling that would otherwise cause or worsen frost. (Low clouds can have a similar "infrared blanket" effect, which is why cloudy nights tend to be warmer than clear-sky nights.)
In 1907, a young inventor, W. C. Scheu, at that time in Grand Junction, Colorado, developed an oil-burning stack heater that was more effective than open fires in heating orchards and vineyards. In 1911, he opened Scheu Manufacturing Company in Upland, California, and began producing a line of orchard heaters. (The firm still exists in 2018.) The use of smudge pots became widespread after a disastrous freeze in Southern California, January 4–8, 1913, wiped out a whole crop.
Smudge pots were commonly used for seven decades in areas such as California's numerous citrus groves and vineyards. The Redlands district had 462,000 orchard heaters for the winter of 1932–33, reported P. E. Simpson, of the supply department of the California Fruit Growers Exchange, requiring 3,693,000 gallons of oil for a single refilling, or about 330 tank car loads. To fill all of the smudge pots in Southern California one time required 2,000 car loads.[7]
Smudge pot use in Redlands, California groves continued into the 1970s, but fell out of favor as oil prices rose and environmental concerns increased. Pots came in two major styles: a single louvered stack above a fuel oil-filled base, and a slightly taller version that featured a cambered, louvered, neck and a galvanized re-breather feed pipe out of the side of the chimney that siphoned stack gas back into the burn chamber and produced more complete combustion. The Return-Stack heater was developed by the University of California and became commercially available about 1940. Filler caps have a three or four hole flue control. The stem into the pot usually has a piece of oil-soaked wood ("down-draft tube and wick") secured inside the neck to aid in lighting the pot. Pots are ignited when the air temperature reaches 29 degrees Fahrenheit (−2 Celsius), and for each additional degree of drop, another hole is opened on the control cap ("draft regulator"). Below 25 degrees, nothing more can be done to enhance the heating effects.