The work was done as a winter chore by many
farmers and as a winter occupation by
icemen. Kept insulated, the ice was preserved for
cold food storage during warm weather, either on the farm or for delivery to residential and commercial customers with
ice boxes. A large
ice trade existed in the 19th and early 20th centuries, until mechanical refrigeration displaced it. Due to its harvesting and trade, ice was considered a "
crop". Ice harvesting generally involved waiting until approximately a foot of ice had built up on the water surface in the winter. The ice would then be cut with either a
handsaw or a powered
saw blade into long continuous strips and then cut into large individual blocks for transport by
wagon back to the
ice house. Because
snow on top of the ice slows freezing, it could be scraped off and piled in
windrows. Alternatively, if the temperature is cold enough, a
snowy surface could be flooded to produce a thicker layer of ice. Ice cutting was a considerable export industry for northern countries in
Scandinavia and
North America during the 19th century. It started in the United States around 1800, and spread to Scandinavia around 1820; by the mid century
Norway had become a major exporter to
England,
Europe, the Mediterranean, and as far away as
Kingdom of Kongo,
Egypt and
New York. Coastal
Telemark had 1,300 workers exporting 125,000 tons in 1895–96, while the Oslo Fjord was the main European export region with
Nesodden municipality alone employing 1,000 men and exporting 95,000 tons in 1900, at a time when Norway's combined ice export at 500,000 tons stood as the world's largest. Domestic production and sales were the largest single market source for ice in America and Europe. From the 1850s onwards ice cutting took on large-scale industrial proportions in
Germany with
Berlin as a key market. In the 1880s,
New York City had over 1500 ice delivery wagons and Americans consumed over 5 million tons of ice annually. ==Modern usage==