smudge pot

noun
1.
a container for burning oil or other fuels to produce smudge, as for protecting fruit trees from frost.
Origin
1880-85
Encyclopedia Article for smudge pot

device, usually an oil container with some crude oil burning in the bottom, used in fruit orchards, especially citrus groves, to provide protection against frost. The smoke serves as a blanket to reduce heat losses due to outgoing radiation. Because of the air pollution they generate smudge pots have been generally supplanted by other means of frost protection, such as smokeless burners using natural gas.

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