EtymologyThe phrase ''z Prus'' ("from ", a region now part of Poland) sounds to English ears like ''spruce''. ''Spruce'', ' (1412), and ' (1378) seem to have been generic terms for commodities brought to England by merchants (especially beer, boards, wooden chests and leather), and the tree thus was believed to be particular to Prussia, which for a time was figurative in England as a land of luxuries. It can be argued that the word is actually derived from the term ''Pruce'', meaning literally Prussia.
Classificationanalyses have shown that traditional classifications based on the of needle and are artificial. A recent study found that '' '' had a position, followed by '' P. sitchensis'', and the other species were further divided into three
SpeciesThirty-five named species of spruce exist in the world. has 59 accepted spruce names. Basal species: * '' '' – Brewer's spruce, , North America; local * '' '' – spruce, Pacific coast of North America; the largest species, to 95 m tall; important in *Clade I (Northern and western , in or high mountains) ** '' '' – Engelmann spruce, western North American mountains; important in forestry ** '' '' – white spruce, northern North America; important in forestry *Clade II (throughout Asia, mostly in mountainous areas, a few isolated populations in higher elevations of ,) ** '' Picea brachytyla'' – Sargent's spruce, southwest ** '' Picea chihuahuana'' – Chihuahua spruce, northwest Mexico (rare) ** '' Picea farreri'' – Burmese spruce, northeast , southwest (mountains) ** '' '' – Likiang spruce, southwest China ** '' Picea martinezii'' – Martinez spruce, northeast Mexico (very rare, endangered) ** '' Picea maximowiczii'' – Maximowicz spruce, (rare, mountains) ** '' Picea morrisonicola'' – Taiwan spruce, (high mountains) ** '' Picea neoveitchii'' – Veitch's spruce, northwest China (rare, endangered) ** '' '' – Caucasian spruce or Oriental spruce, , northeast ** '' Picea purpurea'' – purple cone spruce, western China ** '' Picea schrenkiana'' – Schrenk's spruce, mountains of central Asia ** '' '' – morinda spruce, western , eastern , northern and northwest ** '' Picea spinulosa'' – Sikkim spruce, northeast India ( ), eastern ** '' '' – tiger-tail spruce, Japan ** '' Picea wilsonii'' – Wilson's spruce, western China *Clade III (Europe, Asia, and North America, mostly in boreal forests or mountainous areas) ** '' '' – Norway spruce, Europe; important in forestry, the original ** '' '' – ("''P. bicolor''") Alcock's spruce, central Japan (mountains) ** '' Picea asperata'' – dragon spruce, western China; several varieties ** '' Picea crassifolia'' – Qinghai spruce, China ** '' Picea glehnii'' – Glehn's spruce, northern Japan, ** '' '' – Jezo spruce, northeast Asia, south to Japan ** '' Picea koraiensis'' – Korean spruce, , northeast China ** '' Picea koyamae'' – Koyama's spruce, Japan (mountains) ** '' '' – black spruce, northern North America ** '' Picea meyeri'' – Meyer's spruce, northern China (from Inner Mongolia to Gansu) ** '' '' – Siberian spruce, north , ; often treated as a variant of ''P. abies'' (and hybridises with it), but has distinct cones ** '' '' – Serbian spruce, and ; local ; important in horticulture ** '' '' – blue spruce or Colorado spruce, , North America; important in horticulture ** '' Picea retroflexa'' – green dragon spruce, China ** '' '' – red spruce, northeastern North America; important in forestry, known as in musical-instrument making There is also an extinct species identified from fossil evidence, '' Picea critchfieldii'' which was widespread in the Southeastern United States in the Late Quaternary.
MorphologyDetermining that a tree is a spruce is not difficult; needles that are more or less quadrangled, and especially the , give it away. Beyond that, determination can become more difficult. Intensive sampling in the Smithers/Hazelton/Houston area of British Columbia showed Douglas (1975),Douglas, G.W. (1975). Spruce (''Picea'') hybridization in west-central British Columbia. B.C. Min. For., Forest Science, Smithers BC, unpublished report, cited by Coates et al. 1994. (Cited by Coates et al. 1994, orig. not seen) according to Coates et al. (1994),Coates, K.D.; Haeussler, S.; Lindeburgh, S.; Pojar, R.; Stock, A.J. (1994). Ecology and silviculture of interior spruce in British Columbia. Canada/British Columbia Partnership Agreement For. Resour. Devel., Victoria BC, FRDA Rep. 220. 182 p. that cone scale morphology was the feature most useful in differentiating species of spruce; the length, width, length: width ratio, the length of free scale (the distance from the imprint of the seed wing to the tip of the scale), and the percentage free scale (length of free scale as a percentage of the total length of the scale) were most useful in this regard. Daubenmire (1974), after range-wide sampling, had already recognized the importance of the 2 latter characters. Taylor (1959) (Cited in Coates et al. 1994). had noted that the most obvious morphological difference between typical ''Picea glauca'' and typical ''P. engelmannii'' was the cone scale, and Horton (1956,1959)Horton, K.W. (1956). A taxonomic and ecological study of ''Picea glauca'' and ''Picea engelmannii'' in North America. Diploma thesis, Oxford Univ., U.K. 103 p.Horton, K.W. (1959). Characteristics of subalpine spruce in Alberta. Can. Dep. Northern Affairs National Resour., For. Branch, For. Res. Div., Ottawa ON, Tech. Note 76. 20 p. found that the most useful diagnostic features of the 2 spruces are in the cone; differences occur in the flower, shoot and needle, "but those in the cone are most easily assessed" (Horton 1959). Coupé et al. (1982)Coupé, R.; Ray, C.A.; Comeau, A.; Ketcheson, M.V.; Annas, R.M. (1982). A guide to some common plants of the Skeena area, British Columbia. B.C. Min. For., Res. Branch, Victoria BC. recommended that cone scale characters be based on samples taken from the midsection of each of 10 cones from each of 5 trees in the population of interest. Without cones, morphological differentiation among spruce species and their hybrids is more difficult. Species classification for seeds collected from spruce stands in which introgressive hybridization between white and Sitka spruces (''P. sitchensis'') may have occurred is important for determining appropriate cultural regimens in the nursery. If, for instance, white spruce grown at container nurseries in southwestern British Columbia are not given an extended photoperiod, leader growth ceases early in the first growing season, and seedlings do not reach the minimum height specifications.Arnott, J.T. (1974). "Germination and seedling establishment". pp. 55–66 in Cayford, J.H. (Ed.). ''Direct Seeding Symposium'', Timmins ON, Sept. 1973, Can. Dep. Environ., Can. For. Serv., Ottawa ON, Proc., Publ. 1339. But, if an extended photoperiod is provided for Sitka spruce, seedlings become unacceptably tall by the end of the first growing season . Species classification of seedlots collected in areas where hybridization of white and Sitka spruces has been reported has depended on (i) easily measured cone scale characters of seed trees, especially free scale length, (ii) visual judgements of morphological characters, e.g., growth rhythm, shoot and root weight, and needle serration, or (iii) some combination of (i) and (ii) (Yeh and Arnott 1986). Useful to a degree, these classification procedures have important limitations; genetic composition of the seeds produced by a stand is determined by both the seed trees and the pollen parents, and species classification of hybrid seedlots and estimates of their level of introgression on the basis of seed-tree characteristics can be unreliable when hybrid seedlots vary in their introgressiveness in consequence of spatial and temporal variations in contributions from the pollen parent (Yeh and Arnott 1986). Secondly, morphological characters are markedly influenced by ontogenetic and environmental influences, so that to discern spruce hybrid seedlot composition with accuracy, hybrid seedlots must differ substantially in morphology from both parent species. Yeh and Arnott (1986) pointed out the difficulties of estimating accurately the degree of introgression between white and Sitka spruces; introgression may have occurred at low levels, and/or hybrid seed lots may vary in their degree of introgression in consequence of repeated backcrossing with parental species.
GrowthSpruce seedlings are most susceptible immediately following , and remain highly susceptible through to the following spring. More than half of spruce seedling mortality probably occurs during the first growing season and is also very high during the first winter,Alexander, R.R. (1987). Ecology, silviculture, and management of the Engelmann spruce–subalpine fir type in the central and southern Rocky Mountains. USDA, For. Serv., Washington DC, Agric. Handb. 659. 144 p. when seedlings are subjected to freezing damage, frost heaving and erosion, as well as smothering by litter and snow-pressed vegetation. Seedlings that germinate late in the growing season are particularly vulnerable because they are tiny and have not had time to harden off fully. Mortality rates generally decrease sharply thereafter, but losses often remain high for some years. "Establishment" is a subjective concept based on the idea that once a seedling has successfully reached a certain size, not much is likely to prevent its further development. Criteria vary, of course, but Noble and Ronco (1978),Noble, D.L.; Ronco, F. (1978). Seedfall and establishment of Engelmann spruce and subalpine fir in clearcut openings in Colorado. USDA, For. Serv., Rocky Mountain For. Range Exp. Sta., Res. Pap. RM-200. 12 p. for instance, considered that seedlings 4 to 5 years old, or 8 cm to 10 cm tall, warranted the designation "established", since only unusual factors such as Phacidiaceae, snow mold, Wildfire, fire, Disturbance (ecology), trampling, or predation would then impair regeneration success. Eis (1967) suggested that in dry habitats on either mineral soil or litter seedbeds a 3-year-old seedling may be considered established; in moist habitats, seedlings may need 4 or 5 years to become established on mineral soil, possibly longer on litter seedbeds. Growth remains very slow for several to many years. Three years after Shelterwood cutting, shelterwood felling in subalpine Alberta, dominant Regeneration (biology), regeneration averaged 5.5 cm in height in Scarification, scarified blocks, and 7.3 cm in non-scarified blocks (Day 1970),Day, M.W.; Rudolph, V.J. (1970). Development of a white spruce plantation. Michigan State Univ., Agric. Exp. Sta., East Lansing MI, Res. Pap. 111. 4 p. possibly reflecting diminished fertility with the removal of the A horizon.
TimberSpruce is useful as a building wood, commonly referred to by several different names including North American timber, SPF (spruce, pine, fir) and whitewood (the collective name for spruce wood). Spruce wood is used for many purposes, ranging from general construction work and crates to highly specialised uses in wooden aircraft. The Wright brothers' first aircraft, the ''Wright Flyer, Flyer'', 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 (indoor drywall framing, for example). Spruce wood, when left outside cannot be expected to last more than 12–18 months depending on the type of climate it is exposed to.
PulpwoodSpruce is one of the most important Pulpwood, woods for paper uses, as it has long wood fibres which bind together to make strong paper. The fibres are thin walled and collapse to thin bands upon drying. Spruces are commonly used in mechanical pulping as they are easily Bleaching of wood pulp, bleached. Together with northern pines, northern spruces are commonly used to make NBSK. Spruces are Plantation, cultivated over vast areas as pulpwood.
Food and medicineThe fresh shoots of many spruces are a natural source of vitamin C. Captain Cook made alcoholic sugar-based spruce beer during his sea voyages in order to prevent scurvy in his crew. The leaves and branches, or the essential oils, can be used to brew spruce beer. In Finland, young spruce Bud, buds are sometimes used as a spice, or boiled with sugar to create spruce bud syrup. 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 preventive measure for scurvy in an environment where meat is the only prominent food source .
TonewoodSpruce is the standard material used in soundboards for many musical instruments, including guitars, mandolins, cellos, violins, and the sound board (music), soundboard at the heart of a piano and the harp. Wood used for this purpose is referred to as tonewood. Spruce, along with Thuja plicata, cedar, is often used for the sound board (music), soundboard/top of an acoustic guitar. The main types of spruce used for this purpose are Sitka, Engelmann, Adirondack and European spruces.
Other usesThe resin was used in the manufacture of pitch (resin), pitch in the past (before the use of petrochemicals); the scientific name ''Picea'' derives from Latin "pitch pine" (referring to Scots pine), from , an adjective from "pitch". Indigenous people of the Americas, Native Americans in 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. Spruces are 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 s, with artificial Christmas trees often being produced in their likenesses. 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.
''Sirococcus'' blight (Deuteromycotina, Coelomtcetes)The closely related species ''Sirococcus conigenus'' and ''Sirococcus piceicola, S. piceicola'' cause shoot blight and seedling mortality of Pinophyta, conifers in North America, Europe, and North Africa. Twig blight damage to seedlings of white and Picea rubens, red spruces in a nursery near Asheville, North Carolina, was reported by Graves (1914). Hosts include White spruce, white, Picea mariana, black, Picea engelmannii, Engelmann, Picea abies, Norway, and Picea rubens, red spruces, although they are not the plants most commonly damaged. ''Sirococcus'' blight of spruces in nurseries show up randomly in seedlings to which the fungus was transmitted in infested seed. First-year seedlings are often killed, and larger plants may become too deformed for planting. Outbreaks involving < 30% of spruce seedlings in seedbeds have been traced to seed lots in which only 0.1% to 3% of seeds were infested. Seed infestation has in turn been traced to the colonization of spruce cones by ''S. conigenus'' in forests of the western interior. Infection develops readily if conidia are deposited on succulent plant parts that remain wet for at least 24 hours at 10 °C to 25 °C. Longer periods of wetness favour increasingly severe disease. Twig tips killed during growth the previous year shows a characteristic crook.
''Rhizosphaera kalkhoffi'' needle cast''Rhizosphaera'' infects white spruce, blue spruce (''Picea pungens''), and Norway spruces throughout Ontario, causing severe defoliation and sometimes killing small, stressed trees. White spruce is intermediately susceptible. Dead needles show rows of black fruiting bodies. Infection usually begins on lower branches. On white spruce, infected needles are usually retained on the tree into the following summer. The fungicide Chlorthalonil is registered for controlling this needle cast (Davis 1997).Davis, C. (24 September 1997) "Tree talk". ''The Sault Star''. Marie, Ontario. p. B2.
''Valsa kunzei'' branch and stem cankerA branch and stem canker associated with the fungus ''Valsa kunzei'' Fr. var. ''picea'' was reported on white and Norway spruces in Ontario (Jorgensen and Cafley 1961) and Quebec (Ouellette and Bard 1962). In Ontario, only trees of low vigour were affected, but in Quebec vigorous trees were also infected.
PredatorsSmall mammals consume Pinophyta, conifer seeds, and also eat seedlings. Cage feeding of deer mice (''Peromyscus maniculatus'') and red-backed vole (''Myodes gapperi'') showed a daily maximum seed consumption of 2000 white spruce seeds and of 1000 seeds of Pinus contorta, lodgepole pine, with the 2 species of mice consuming equal amounts of seed, but showing a preference for the pine over the spruce (Wagg 1963). The short-tailed meadow vole (''Microtus pennsylvanicus'' Ord) voraciously ate all available white spruce and lodgepole pine seedlings, pulling them out of the ground and holding them between their front feet until the whole seedling had been consumed. Wagg (1963) attributed damage observed to the bark and cambium at ground level of small white spruce seedlings over several seasons to meadow voles. Once shed, seeds contribute to the diet of small mammals, e.g., Peromyscus, deer mice, red-backed voles, Montane vole, mountain voles (''Microtus montanus''), and chipmunks (''Eutamias minimus''). The magnitude of the loss is difficult to determine, and studies with and without seed protection have yielded conflicting results. In western Montana, for example, spruce seedling success was little better on protected than on unprotected seed spots (Schopmeyer and Helmers 1947),Schopmeyer, C.S.; Helmers, A.E. 1947. Seeding as a means of reforestation in the northern Rocky Mountain Region. USDA For. Serv., Washington DC, Circular 772. 30 p. but in British Columbia spruce regeneration depended on protection from rodents (Smith 1955).Smith, J.H.G. 1955 [1956 acc to E3999 bib]. Some factors affecting reproduction of Engelmann spruce and alpine fir. British Columbia Dep. Lands For., For. Serv., Victoria BC, Tech. Publ. 43 p. [Coates et al. 1994, Nienstaedt and Teich 1972] An important albeit indirect biotic constraint on spruce establishment is the depredation of seed by squirrels. As much as 90% of a cone crop has been harvested by red squirrels (Zasada et al. 1978).Zasada, J.C.; Foote, M.J.; Deneke, F.J.; Parkerson, R.H. 1978. Case history of an excellent white spruce cone and seed crop in interior Alaska: cone and seed production, germination and seedling survival. USDA, For. Serv., Pacific NW For. Range Exp. Sta., Portland OR, Gen. Tech. Rep. PNW-65. 53 p. Deer mice, voles, chipmunks, and shrews can consume large quantities of seed; 1 mouse can eat 2000 seeds per night. Repeated applications of half a million seeds/ha failed to produce the 750 trees/ha sought by Northwest Pulp and Power, Ltd., near Hinton, Alberta (Radvanyi 1972),Radvanyi, A. 1972. Small mammals and regeneration of white spruce in western Alberta. p. 21–23 ''in'' McMinn, R.G. (Ed.). White Spruce: Ecology of a Northern Resource. Can. Dep. Environ., Can. For. Serv., Edmonton AB, Inf. Rep. NOR-X-40. but no doubt left a lot of well-fed small mammals. Foraging by squirrels for winter buds (Rowe 1952)Rowe, J.S. 1952. Squirrel damage to white spruce. Can. Dep. Resour. Devel., For. Branch, For. Res. Div., Ottawa ON, Silv. Leafl. 61. 2 p. has not been reported in relation to young plantations, but Wagg (1963) noted that at Hinton AB, red squirrels were observed cutting the lateral and terminal twigs and feeding on the vegetative and flower buds of white spruce. American red squirrel, Red squirrels in Alaska have harvested as much as 90% of a cone crop (Zasada et al. 1978); their ''modus operandi'' is to cut off great numbers of cones with great expedition early in the fall, and then "spend the rest of the fall shelling out the seeds". In Manitoba, Rowe (1952) ascribed widespread severing of branch tips 5 cm to 10 cm long on white spruce ranging "from sapling to veteran size" to squirrels foraging for winter buds, cone failure having excluded the more usual food source. The damage has not been reported in relation to small trees, outplants or otherwise. Porcupines (''Erethizon dorsatum'' L.) may damage spruce (Nienstaedt 1957),Nienstaedt, H. 1957. Silvical characteristics of white spruce (''Picea glauca''). USDA, For. Serv., Lake States For. Exp. Sta., St. Paul MN, Pap. 55. 24 p. but prefer red pine. Bark-stripping of white spruce by black bear (''Euarctos americanus perniger'') is locally important in Alaska (Lutz 1951), but the bark of white spruce is not attacked by field mice (''Microtus pennsylvanicus'' Ord), even in years of heavy infestation.
PestsThe (''Choristoneura fumiferana'') is a major pest of spruce trees in forests throughout Canada and the eastern United States. Two of the main host plants are Picea mariana, black spruce and white spruce.Balch, R.E.; Webb, F.E.; Morris, R.F. (1954)
GenomeThe nuclear, mitochondrial and chloroplast genomes of British Columbia interior spruce have been sequenced. The large (20 Gbp) nuclear genome and associated gene annotations of interior spruce (genotype PG29) were published in 2013 and 2015.