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Spruce

Species of spruce

Economic and ecological importance of spruces

Spruces are species of trees in the genus Picea, family Pinaceae. The natural range of spruces is the Northern Hemisphere, where these trees occur in boreal and cool-temperate climates. These climates are common at high altitudes on the slopes of mountains and at high latitudes towards the north, south of the arctic tundra.

Spruces sometimes dominate the forests in which they occur, or sometimes they are present in combination with other conifer species. Spruces are also common major or minor components of mixed-species forests with various angiosperm species of trees.

Short, needle-like, sharply pointed, evergreen foliage that grows from a peg like base of the spruce may persist on the branches for as long as a decade. The crown of spruce trees is typically spire like in shape. The bark is rough and scaly, and it oozes a resin known as sprucegum from wounds. Mature spruce trees develop male and female flowers, known as strobili, in the springtime. The downward-hanging, egg-shaped, woody cones of spruces mature by the end of the growing season.

Species of spruce

Many species of spruce will interbreed with each other, sometimes forming populations of hybrids that are fertile and have characteristics intermediate to those of the parents. When hybridization occurs in a genus, it is difficult for taxonomists to decide the exact number of species that are present. As a result, it is estimated that there are 35-40 species of spruces, depending on which taxonomic treatment is adopted. There are also a number of well-defined hybrids between some of the true species.

Seven species of spruces occur in North America, and some additional species have been widely planted in forestry or horticulture. The richness of native spruce species is greatest in China, where 18 species occur.

The most widespread species of spruce in North America is white spruce (Picea glauca), which ranges through almost all of boreal and temperate Canada and the northeastern United States. Black spruce (P. mariana) has a somewhat less extensive, more northern distribution, and it tends to occur in wetter sites than white spruce, including bogs. Red spruce (P. rubens) occurs in eastern Canada and New England and at high altitudes in the Appalachians.

The other spruces of North America are western in distribution. Engelmann spruce (P. engelmannii) isa widespread, montane species in the Rocky Mountains. Blue spruce (P. pungens) occurs in the southern Rocky Mountains. Sitka spruce (P. sitchensis) is widespread in humid forests of the west coast, ranging from southern Alaska to central California. Brewer spruce (P. breweriana) has a very restricted distribution in southern Oregon.

The Norway spruce (P. abies) is the most widespread species in western and central Europe. This species occurs naturally in that region, and it has also been cultivated as an economic species for at least three centuries. Norway spruce has also been introduced to North America for use in forestry and for planting in parks and around homes.

Economic and ecological importance of spruces

Spruces are commonly harvested for use in the manufacturing of pulp, paper, and cardboard. Spruces are excellent raw material for these uses because their light-colored wood has relatively long and straight fibers. In addition, the celluloseconcentration of the wood is high, while the concentrations of tannins, gums, resins, and other waste components are relatively small.

Spruce logs are also sawn into lumber and other wood products and used to build structures, furniture, and other value-added products. Larger spruce logs may also be used to manufacture plywood and other composite materials.

These uses of spruces in the forest industries are very important economically throughout the range of these trees in the Northern Hemisphere and elsewhere. Depending on the local ecological conditions and the type of forestry being practiced, the post-harvest regeneration may rely on small spruce plants that were present before the harvest, on seedlings that establish naturally afterwards, or on seedlings that are deliberately planted. Subsequent management of spruce plantations may include the use of herbicides to reduce the competition from weeds, and thereby increase the growth rate of the economically valued spruce trees. The plantation may also be thinned to achieve optimal spacing, and insecticides may be sprayed if there is an epidemic of a significantly damaging insect.

A relatively minor use of spruce bark is for the commercial extraction of tannins, chemicals useful in the tanning of raw animal skins into leather. Sometimes, spruce gum, especially of red spruce, is collected and used as a chewing gum with a pleasant, resinous taste. The spruce gum must be properly aged for this particular usage.

Spruces are also commonly used for horticultural purposes. In North America, use is most frequently made of native white spruce, red spruce, and blue spruce, a species that is particularly attractive because of its glaucous, bluish foliage. The Norway spruce of Europe and tigertail spruce (P. polita) of China are also widely planted as ornamentals in North America.

In the winter, spruce trees are commonly harvested for use as Christmas trees. They do well for this purpose, although they tend to shed their leaves if they are kept in a warm, dry, indoor environment for too long.

Many species of resident and migratory wildlife require spruce-dominated forests as their critical habitat for breeding or other purposes. Spruces are important because they provide habitat for these species of plant and animal wildlife over great regions of the Northern Hemisphere.

Because they are the dominant trees of many types of forests, spruces also confer a major element of the aesthetics of many remote landscapes. This is a major service of spruces because of the increasingly important economic impact of outdoor recreation and ecotourism.

See also Pesticides.

Bill Freedman

views updated

Spruce

Spruces are species of trees in the genus Picea, family Pinaceae. The natural range of spruces is the Northern Hemisphere, where these trees occur in boreal and cool-temperate climates. These climates are common at high altitudes on the slopes of mountains and at high latitudes towards the north, south of the arctic tundra .

Spruces sometimes dominate the forests in which they occur, or sometimes they are present in combination with other conifer species. Spruces are also common major or minor components of mixed-species forests with various angiosperm species of trees.

Short, needle-like, sharply pointed, evergreen foliage that grows from a peg-like base of the spruce may persist on the branches for as long as a decade. The crown of spruce trees is typically spire-like in shape. The bark is rough and scaly, and it oozes a resin known as spruce "gum" from wounds. Mature spruce trees develop male and female flowers, known as strobili, in the springtime. The downward-hanging, egg-shaped, woody cones of spruces mature by the end of the growing season.

Species of spruce

Many species of spruce will interbreed with each other, sometimes forming populations of hybrids that are fertile and have characteristics intermediate to those of the parents. When hybridization occurs in a genus, it is difficult for taxonomists to decide the exact number of species that are present. As a result, it is estimated that there are 35-40 species of spruces, depending on which taxonomic treatment is adopted. There are also a number of well-defined hybrids between some of the true species.

Seven species of spruces occur in North America , and some additional species have been widely planted in forestry or horticulture . The richness of native spruce species is greatest in China, where 18 species occur.

The most widespread species of spruce in North America is white spruce (Picea glauca), which ranges through almost all of boreal and temperate Canada and the northeastern United States. Black spruce (P. mariana) has a somewhat less extensive, more northern distribution, and it tends to occur in wetter sites than white spruce, including bogs. Red spruce (P. rubens) occurs in eastern Canada and New England and at high altitudes in the Appalachians.

The other spruces of North America are western in distribution. Engelmann spruce (P. engelmannii) is a widespread, montane species in the Rocky Mountains. Blue spruce (P. pungens) occurs in the southern Rocky Mountains. Sitka spruce (P. sitchensis) is widespread in humid forests of the west coast, ranging from southern Alaska to central California. Brewer spruce (P. breweriana) has a very restricted distribution in southern Oregon.

The Norway spruce (P. abies) is the most widespread species in western and central Europe . This species occurs naturally in that region, and it has also been cultivated as an economic species for at least three centuries. Norway spruce has also been introduced to North America for use in forestry and for planting in parks and around homes.


Economic and ecological importance of spruces

Spruces are commonly harvested for use in the manufacturing of pulp, paper , and cardboard. Spruces are excellent raw material for these uses because their light-coloredwood has relatively long and straight fibers. In addition, the cellulose concentration of the wood is high, while the concentrations of tannins, gums, resins , and other waste components are relatively small.

Spruce logs are also sawn into lumber and other wood products and used to build structures, furniture, and other value-added products. Larger spruce logs may also be used to manufacture plywood and other composite materials .

These uses of spruces in the forest industries are very important economically throughout the range of these trees in the Northern Hemisphere and elsewhere. Depending on the local ecological conditions and the type of forestry being practiced, the post-harvest regeneration may rely on small spruce plants that were present before the harvest, on seedlings that establish naturally afterwards, or on seedlings that are deliberately planted. Subsequent management of spruce plantations may include the use of herbicides to reduce the competition from weeds, and thereby increase the growth rate of the economically valued spruce trees. The plantation may also be thinned to achieve optimal spacing, and insecticides may be sprayed if there is an epidemic of a significantly damaging insect.

A relatively minor use of spruce bark is for the commercial extraction of tannins, chemicals useful in the tanning of raw animal skins into leather. Sometimes, spruce gum, especially of red spruce, is collected and used as a chewing gum with a pleasant, resinous taste. The spruce gum must be properly aged for this particular usage.

Spruces are also commonly used for horticultural purposes. In North America, use is most frequently made of native white spruce, red spruce, and blue spruce, a species that is particularly attractive because of its glaucous, bluish foliage. The Norway spruce of Europe and tigertail spruce (P. polita) of China are also widely planted as ornamentals in North America.

In the winter, spruce trees are commonly harvested for use as Christmas trees. They do well for this purpose, although they tend to shed their leaves if they are kept in a warm, dry, indoor environment for too long.

Many species of resident and migratory wildlife require spruce-dominated forests as their critical habitat for breeding or other purposes. Spruces are important because they provide habitat for these species of plant and animal wildlife over great regions of the Northern Hemisphere

Because they are the dominant trees of many types of forests, spruces also confer a major element of the aesthetics of many remote landscapes. This is a major service of spruces because of the increasingly important economic impact of outdoor recreation and ecotourism .

See also Pesticides.


Bill Freedman

views updated

spruce1 / sproōs/ • n. a widespread coniferous tree (genus Picea) of the pine family that has a distinctive conical shape and hanging cones, widely grown for timber, pulp, and Christmas trees. spruce2 • adj. neat in dress and appearance: he looked as spruce as if he were getting married. • v. [tr.] (spruce someone/something up) make a person or place smarter or tidier: the fund will be used to spruce up historic buildings. DERIVATIVES: spruce·ly adv. spruce·ness n.

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spruceabstruse, abuse, adduce, Ballets Russes, Belarus, Bruce, burnous, caboose, charlotte russe, conduce, deduce, deuce, diffuse, douce, educe, excuse, goose, induce, introduce, juice, Larousse, loose, luce, misuse, moose, mousse, noose, obtuse, Palouse, papoose, produce, profuse, puce, recluse, reduce, Rousse, seduce, sluice, Sousse, spruce, traduce, truce, use, vamoose, Zeus •cayuse • calaboose • mongoose •Aarhus • verjuice • couscous •footloose • ventouse • refuse •Odysseus • Idomeneus • hypotenuse •Syracuse

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spruce Various evergreen trees, related to firs, native to mountainous or cooler temperate regions of the Northern Hemisphere. Pyramid-shaped and dense, they have angular rather than flattened needles and pendulous cones. The timber is used in cabinet-making, and some species yield turpentine. Height: to 52m (170ft). Family Pinaceae; genus Picea.

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spruce †brisk, lively; trim, neat. XVI. poss. from a particular collocation of Spruce = Pruce Prussia, e.g. Spruce leather (jerkin).
Hence vb. XVI.

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spruce See PICEA.

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