White Spruce taiga, Denali Highway, Alaska Range, Alaska.
A spruce is a tree of the genus Picea (pronounced /paÉªËsiË.É/), a genus of about 35 species of coniferous evergreen trees in the Family Pinaceae, found in the northern temperate and boreal (taiga) regions of the earth. Spruces are large trees, from 20â60 metres (66â200 ft) tall when mature, and can be distinguished by their whorled branches and conical form. The needles, or leaves, of spruce trees are attached singly to the branches in a spiral fashion, each needle on a small peg-like structure called a pulvinus. The needles are shed when 4â10 years old, leaving the branches rough with the retained pulvinus (an easy means of distinguishing them from other similar genera, where the branches are fairly smooth).
Spruces are used as food plants by the larvae of some Lepidoptera species; see list of Lepidoptera that feed on spruces. They are also used by the larvae of Gall Adelgids (Adelges species).
Scientists have found a cluster of Norway Spruce in the mountains in western Sweden, nicknamed Old Tjikko, which at an age of 9,550 years are claimed to be the world's oldest known living trees.
DNA analyses have shown that traditional classifications based on the morphology of needle and cone are artificial. A recent study found that P. breweriana had a basal position, followed by P. sitchensis, and the other species were further divided into three clades, suggesting that Picea originated in North America.
There are thirty-five named species of spruce.
 Clade I
 Clade II
 Clade III
 Clade IV
 Clade V
Spruce is one of the most important woods for paper uses, as it has long wood fibres which bind together to make strong paper. Spruces are cultivated over vast areas for this purpose. Also, they are useful for building wood.
Spruces are also popular ornamental trees in horticulture, admired for their evergreen, symmetrical narrow-conic growth habit. For the same reason, some (particularly Picea abies and P. omorika) are also extensively used as Christmas trees.
Spruce wood, often called whitewood, is used for many purposes, ranging from general construction work and crates to highly specialised uses in wooden aircraft and many musical instruments, including guitars, mandolins, cellos, violins, and the soundboard at the heart of a piano. The Wright Brothers' first aircraft was built of spruce.
Because this species has no insect or decay resistance qualities after logging, it is generally recommended for construction purposes as indoor use only (ex. indoor drywall framing).
This wood, when left outside can not be expected to last more than 12â18 months depending on the type of climate it is exposed to. It is commonly referred to by several different names which include North American timber, SPF (spruce, pine, fir) and whitewood.
The resin was used in the manufacture of pitch in the past (before the use of petrochemicals); the scientific name Picea is generally thought to be derived from Latin pix, pitch (though other etymologies have been suggested).
The leaves and branches, or the essential oils, can be used to brew spruce beer. The tips from the needles can be used to make spruce tip syrup . Native Americans in North America use the thin, pliable roots of some species for weaving baskets and for sewing together pieces of birch bark for canoes. See also Kiidk'yaas for an unusual golden Sitka Spruce sacred to the Haida people. Native Americans in New England also used the sap to make a gum which was used for various reasons, and which was the basis of the first commercial production of chewing gum.
In survival situations spruce needles can be directly ingested or boiled into a tea. This replaces large amounts of vitamin C. Also, water is stored in a spruce's needles, providing an alternative means of hydration . Spruce can be used as a preventative measure for scurvy in an environment where meat is the only prominent food source .
Spruce branches are also used at Aintree racecourse, Liverpool, to build several of the fences on the Grand National course. It is also used to make sculptures and Christmas trees.
The word "spruce" entered the English language from Old French "Pruce", the name of Prussia. Spruce was a generic term for commodities brought to England by Hanseatic merchants and the tree was believed to have come from Prussia. According to a different theory, some suggest that it may however be a direct loanword from a Polish expression "[drzewo / drewno] z Prus" which literally means "[tree / timber] from Prussia". That would suggest that the late mediaeval Polish-speaking merchants would import the timber to England and the English would pick up the expression from them.
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