Nordic Iron Age Based on chemical analysis of organic residues, there are strong indications that cone-shaped pits discovered north of Uppsala, Sweden, have been used for pine tar production. Three of the pits have been
radiocarbon dated. The oldest dates back to 540–380 BCE, which would make it the world's oldest known, still existing tar production facility. The other dates from 230–390 CE.
Classical antiquity In his encyclopedic work
Natural History () the Roman naturalist and author
Pliny the Elder (23/24–79 CE) describes how, in Europe, tar is produced through the destructive distillation of pine wood. The wood was chopped into small pieces (billets) and heated in a furnace. The tar was used "for coating ships and for many other useful purposes."
17th century Finland Pine tar has long been used in Nordic nations as a preservative for wood which may be exposed to harsh conditions, including outdoor furniture and
ship decking and
rigging. Tar demand surged in the 17th century as European nations began constructing naval and merchant fleets that required tar and pitch for ship waterproofing and
caulking. In Finland, then a part of Sweden, large-scale tar production began in the early 17th century. By the late 17th century, tar was Sweden's third most valuable export commodity.
North American colonies Tar and
pitch for maritime use was in such demand that it became an important export for the American colonies, which had extensive pine forests. North Carolinians became known as "
Tar Heels."
18th–19th century Sweden In present-day Sweden, large-scale tar production started around 1700. Swedish pine tar was often called "Stockholm tar" since, for many years, a single company held a
royal monopoly on its export out of
Stockholm, Sweden. It was also known as "
Archangel Tar". Stockholm tar became synonymous with top-quality tar. Tar production peaked around the mid-1850s and gradually declined thereafter, largely due to new shipbuilding materials reducing the need for tar as a waterproofing agent, and to the decreasing use of hemp rope as sailing ships were phased out. ==Chemical composition==