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A spruce is a
tree In botany, a tree is a perennial plant with an elongated Plant stem, stem, or trunk (botany), trunk, supporting branches and leaves in most species. In some usages, the definition of a tree may be narrower, including only wood plants with se ...

tree
of the genus ''Picea'' , a genus of about 35 species of
conifer Conifers are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single e ...
ous
evergreen In botany Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Anc ...

evergreen
trees in the family
Pinaceae The Pinaceae, pine family, are conifer Conifers are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Con ...

Pinaceae
, found in the northern
temperate In geography Geography (from Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Europe. Its populati ...
and
boreal Boreal, meaning "(far) northern" in Latin and Greek language, Greek, may refer to: Climatology and geography *Boreal (age), the first climatic phase of the Blytt-Sernander sequence of northern Europe, during the Holocene epoch *Boreal climate, a c ...
(
taiga Taiga (; rus, тайга́, p=tɐjˈɡa; relates to Mongolic and Turkic Turkic may refer to: * anything related to the country of Turkey * Turkic languages, a language family of at least thirty-five documented languages ** Turkic alphabets (d ...

taiga
) regions of the Earth. ''Picea'' is the sole genus in the
subfamily In biological classification In biology, taxonomy () is the scientific study of naming, defining (Circumscription (taxonomy), circumscribing) and classifying groups of biological organisms based on shared characteristics. Organisms are grou ...
Piceoideae. Spruces are large trees, from about 20 to 60 m (about 60–200 ft) tall when mature, and have whorled branches and
conical A cone is a three-dimensional space, three-dimensional geometric shape that tapers smoothly from a flat base (frequently, though not necessarily, circular) to a point called the Apex (geometry), apex or vertex (geometry), vertex. A cone is for ...

conical
form. They can be distinguished from other members of the pine family by their needles (leaves), which are four-sided and attached singly to small persistent peg-like structures (
pulvini 200px, Section through the pulvinus of '' Oxalis rosea'', from: Charles Darwin (1880): ''The Power of Movement in Plants">Charles_Darwin.html" ;"title="Oxalis rosea'', from: Charles Darwin">Oxalis rosea'', from: Charles Darwin (1880): ''The Power of ...
or
sterigmata In biology, a sterigma (pl. sterigmata) is a small supporting structure. It commonly refers to an extension of the basidium (the spore-bearing cells) consisting of a basal filamentous part and a slender projection which carries a spore at the t ...
) on the branches, and by their
cones A cone is a three-dimensional space, three-dimensional geometric shape that tapers smoothly from a flat base (frequently, though not necessarily, circular) to a point called the Apex (geometry), apex or vertex (geometry), vertex. A cone is fo ...
(without any protruding
bract ''). All the "leaves" in this image are bracts. In botany Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in th ...

bract
s), which hang downwards after they are pollinated. The needles are shed when 4–10 years old, leaving the branches rough with the retained pegs. In other similar genera, the branches are fairly smooth. Spruce are used as food plants by the
larva A larva (plural larvae ) is a distinct juvenile form many animal Animals (also called Metazoa) are multicellular A multicellular organism is an organism In biology, an organism () is any organic, life, living system that f ...
e of some
Lepidoptera Lepidoptera ( ; ) is an order Order or ORDER or Orders may refer to: * Orderliness Orderliness is associated with other qualities such as cleanliness Cleanliness is both the abstract state of being clean and free from germs, dirt, trash, or ...

Lepidoptera
(moth and butterfly) species, such as the
eastern spruce budworm
eastern spruce budworm
. They are also used by the larvae of
gall adelgid The gall adelgid (''Adelges cooleyi'') is an adelgid species that produces gall Galls can also appear on skeletal animals and in the fossil record. Two galls with perforations on a crinoid stem (''Apiocrinites negevensis'') from the Middle Ju ...
s (''Adelges'' species). In the mountains of western
Sweden Sweden ( sv, Sverige ), officially the Kingdom of Sweden ( sv, links=no, Konungariket Sverige ), is a Nordic country The Nordic countries, or the Nordics, are a geographical and cultural region In geography, regions are areas that ...

Sweden
, scientists have found a
Norway spruce ''Picea abies'', the Norway spruce or European spruce, is a species of spruce native to Northern Europe, Northern, Central Europe, Central and Eastern Europe. It has branchlets that typically hang downwards, and the largest cones of any spruce, 9 ...
, nicknamed
Old Tjikko Old Tjikko is a 9,550 year-old Norway spruce ''Picea abies'', the Norway spruce or European spruce, is a species of native to , and . It has s that typically hang downwards, and the largest cones of any , 9–17 cm long. It is very closely ...

Old Tjikko
, which by reproducing through
layering Layering has evolved as a common means of vegetative propagation of numerous species in natural environments. Layering is also utilized by horticulturists to propagate desirable plants. Natural layering typically occurs when a branch touches th ...

layering
, has reached an age of 9,550 years and is claimed to be the world's oldest known living tree.


Etymology

The
Polish Polish may refer to: * Anything from or related to Poland Poland ( pl, Polska ), officially the Republic of Poland ( pl, Rzeczpospolita Polska, links=no ), is a country located in Central Europe. It is divided into 16 Voivodeships of Pol ...
phrase ''z Prus'' ("from
Prussia Prussia, , Old Prussian Distribution of the Baltic tribes, circa 1200 CE (boundaries are approximate). Old Prussian was a Western Baltic language belonging to the Balto-Slavic branch of the Indo-European languages The Indo-Europ ...

Prussia
", 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
Hanseatic The Hanseatic League (; gml, Hanse, , ; german: label=German language, Modern German, Deutsche Hanse; nl, label=Dutch language, Dutch, De Hanze; la, Hansa Teutonica) was a Middle Ages, medieval commercial and defensive confederation of mercha ...
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
Old French Old French (, , ; Modern French French ( or ) is a Romance language The Romance languages, less commonly Latin or Neo-Latin languages, are the modern languages that evolved from Vulgar Latin Vulgar Latin, also known as Popular o ...
term ''Pruce'', meaning literally Prussia.


Classification

DNA Deoxyribonucleic acid (; DNA) is a molecule File:Pentacene on Ni(111) STM.jpg, A scanning tunneling microscopy image of pentacene molecules, which consist of linear chains of five carbon rings. A molecule is an electrically neutral gro ...

DNA
analyses have shown that traditional classifications based on the
morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines * Morphology (archaeology), study of the shapes or forms of artifacts * Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies ...
of needle and
cone A cone is a three-dimensional Three-dimensional space (also: 3-space or, rarely, tri-dimensional space) is a geometric setting in which three values (called parameter A parameter (from the Ancient Greek language, Ancient Greek wikt:πα ...
are artificial. A recent study found that ''
P. breweriana
P. breweriana
'' had a
basal Basal or basilar is a term meaning ''base'', ''bottom'', or ''minimum''. Science * Basal (anatomy), an anatomical term of location for features associated with the base of an organism or structure * Basal (medicine), a minimal level that is neces ...
position, followed by '' P. sitchensis'', and the other species were further divided into three
clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyly, monophyletic – that is, composed of a common ancestor and all its lineage (evolution), lineal descendants - on a phylogenetic tree. R ...

clade
s, suggesting that ''Picea'' originated in North America. The oldest record of spruce has been found in the fossil record from the Early Cretaceous around 136 million years ago.


Species

Thirty-five named species of spruce exist in the world.
The Plant List The Plant List is a list of botanical name A botanical name is a formal scientific name In taxonomy Taxonomy (general) is the practice and science of classification of things or concepts, including the principles that underlie such clas ...
has 59 accepted spruce names. Basal species: * '''' – Brewer's spruce,
Klamath Mountains The Klamath Mountains are a rugged and lightly populated mountain range in northwestern California and southwestern Oregon in the western United States. As a mountain system within both the greater Pacific Coast Ranges and the California Coast Ran ...
, North America; local
endemic Endemism is the state of a species In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest gro ...
* ''
Picea sitchensis ''Picea sitchensis'', the Sitka spruce, is a large, conifer Conifers are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known a ...
'' – spruce, Pacific coast of North America; the largest species, to 95 m tall; important in
forestry Forestry is the science and craft of creating, managing, planting, using, conserving and repairing forest A forest is an area of land dominated by tree In botany, a tree is a perennial plant with an elongated Plant stem, ste ...
*Clade I (Northern and western
North America North America is a continent A continent is any of several large landmasses. Generally identified by convention (norm), convention rather than any strict criteria, up to seven geographical regions are commonly regarded as continen ...

North America
, in or high mountains) ** ''
Picea engelmannii ''Picea engelmannii'', with common names Engelmann spruce, white spruce, mountain spruce, or silver spruce, is a species of spruce A spruce is a tree of the genus ''Picea'' , a genus of about 35 species of coniferous evergreen trees in the fam ...

Picea engelmannii
'' – Engelmann spruce, western North American mountains; important in forestry ** ''
Picea glauca A spruce is a tree In botany, a tree is a perennial plant with an elongated Plant stem, stem, or trunk (botany), trunk, supporting branches and leaves in most species. In some usages, the definition of a tree may be narrower, including ...

Picea glauca
'' – white spruce, northern North America; important in forestry *Clade II (throughout Asia, mostly in mountainous areas, a few isolated populations in higher elevations of
Mexico Mexico, officially the United Mexican States, is a country A country is a distinct territorial body or political entity A polity is an identifiable political entity—any group of people who have a collective identity, who are organi ...

Mexico
,) ** '' Picea brachytyla'' – Sargent's spruce, southwest
China China (), officially the People's Republic of China (PRC; ), is a country in East Asia East Asia is the eastern region of Asia Asia () is Earth's largest and most populous continent, located primarily in the Eastern Hemisphere ...

China
** '' Picea chihuahuana'' – Chihuahua spruce, northwest Mexico (rare) ** '' Picea farreri'' – Burmese spruce, northeast
Burma Myanmar (; my, မြန်မာ ) or Burma ( my, ဗမာ ), officially the Republic of the Union of Myanmar, is a country in Southeast Asia. Myanmar is bordered by Bangladesh and India to its northwest, China to its northeast, Laos a ...

Burma
, southwest
China China (), officially the People's Republic of China (PRC; ), is a country in East Asia East Asia is the eastern region of Asia Asia () is Earth's largest and most populous continent, located primarily in the Eastern Hemisphere ...

China
(mountains) ** '''' – Likiang spruce, southwest China ** '' Picea martinezii'' – Martinez spruce, northeast Mexico (very rare, endangered) ** '' Picea maximowiczii'' – Maximowicz spruce,
Japan Japan ( ja, 日本, or , and formally ) is an island country An island country or an island nation is a country A country is a distinct territory, territorial body or political entity. It is often referred to as the land of an in ...

Japan
(rare, mountains) ** '' Picea morrisonicola'' – Taiwan spruce,
Taiwan Taiwan, officially the Republic of China (ROC), is a country in East Asia East Asia is the eastern region of Asia Asia () is Earth's largest and most populous continent, located primarily in the Eastern Hemisphere, Eastern and N ...

Taiwan
(high mountains) ** '' Picea neoveitchii'' – Veitch's spruce, northwest China (rare, endangered) ** '''' – Caucasian spruce or Oriental spruce,
Caucasus The Caucasus (), or Caucasia (), is a region spanning Europe and Asia. It is situated between the Black Sea and the Caspian Sea and mainly occupied by Armenia, Azerbaijan, Georgia (country), Georgia, and parts of Southern Russia. It is home to ...
, northeast
Turkey Turkey ( tr, Türkiye ), officially the Republic of Turkey, is a country located mainly on Anatolia Anatolia,, tr, Anadolu Yarımadası), and the Anatolian plateau. also known as Asia Minor, is a large peninsula in Western Asia an ...

Turkey
** '' Picea purpurea'' – purple cone spruce, western China ** '' Picea schrenkiana'' – Schrenk's spruce, mountains of central Asia ** ''
Picea smithiana ''Picea smithiana'' is a species of evergreen tree in the family Pinaceae family It is referred to by the common names morinda spruce and West Himalayan spruce, and is a spruce native to the western Himalaya and adjacent mountains, from northeast ...

Picea smithiana
'' – morinda spruce, western
Himalaya The Himalayas, or Himalaya (; Sanskrit: , "snow", "dwelling", "abode"), are a mountain range in Asia separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has some of the planet's highest peaks, including the ...

Himalaya
, eastern
Afghanistan Afghanistan (; Pashto Pashto (,; / , ), sometimes spelled Pukhto or Pakhto, is an Eastern Iranian language The Eastern Iranian languages are a subgroup of the Iranian languages The Iranian or Iranic languages are a branch of t ...

Afghanistan
, northern and northwest
India India, officially the Republic of India (Hindi Hindi (Devanagari: , हिंदी, ISO 15919, ISO: ), or more precisely Modern Standard Hindi (Devanagari: , ISO 15919, ISO: ), is an Indo-Aryan language spoken chiefly in Hindi Belt, ...

India
** '' Picea spinulosa'' – Sikkim spruce, northeast India (
Sikkim Sikkim (; ) is a state State may refer to: Arts, entertainment, and media Literature * ''State Magazine'', a monthly magazine published by the U.S. Department of State * The State (newspaper), ''The State'' (newspaper), a daily newspaper in ...

Sikkim
), eastern
Himalaya The Himalayas, or Himalaya (; Sanskrit: , "snow", "dwelling", "abode"), are a mountain range in Asia separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has some of the planet's highest peaks, including the ...

Himalaya
** '''' – 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) ** ''
Picea abies ''Picea abies'', the Norway spruce or European spruce, is a species of spruce A spruce is a tree of the genus ''Picea'' , a genus of about 35 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and bor ...

Picea abies
'' – Norway spruce, Europe; important in forestry, the original
Christmas tree A Christmas tree is a decorated tree, usually an evergreen In botany Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist ...

Christmas tree
** '''' – ("''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,
Sakhalin Sakhalin; ja, 樺太 ''Karafuto'') is the largest island of Russia Russia ( rus, link=no, Россия, Rossiya, ), or the Russian Federation, is a country spanning Eastern Europe Eastern Europe is the eastern region of Europe. The ...

Sakhalin
** ''
Picea jezoensis ''Picea jezoensis'' (sometimes misspelled ''Picea yezoensis''), the dark-bark spruce, Ezo spruce, Yezo spruce, or Jezo spruce, is a large evergreen tree growing to 30–50 m tall and with a trunk diameter of up to 2 m. It is native to northeast A ...

Picea jezoensis
'' – Jezo spruce, northeast Asia,
Kamchatka The Kamchatka Peninsula (, ''Poluostrov Kamchatka'', ) is a peninsula A peninsula ( la, paeninsula from ' "almost" and ' "island") is a landform surrounded by water on most of its border while being connected to a mainland from which it e ...

Kamchatka
south to Japan ** '' Picea koraiensis'' – Korean spruce,
Korea Korea is a region In geography, regions are areas that are broadly divided by physical characteristics (physical geography), human impact characteristics (human geography), and the interaction of humanity and the environment (environmental ...

Korea
, northeast China ** '' Picea koyamae'' – Koyama's spruce, Japan (mountains) ** ''
Picea mariana ''Picea mariana'', the black spruce, is a North America North America is a continent A continent is any of several large landmasses. Generally identified by convention (norm), convention rather than any strict criteria, up to s ...

Picea mariana
'' – black spruce, northern North America ** '' Picea meyeri'' – Meyer's spruce, northern China (from Inner Mongolia to Gansu) ** ''
Picea obovata ''Picea obovata'', the Siberian spruce, is a spruce A spruce is a tree of the genus ''Picea'' , a genus of about 35 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal ecosystem, boreal (ta ...
'' – Siberian spruce, north
Scandinavia Scandinavia; Sami Places * Sápmi, a cultural region in Northern Europe * Sami, Burkina Faso, a district of the Banwa Province * Sami District, Gambia * Sami, Cephalonia, a municipality in Greece * Sami (ancient city), in Elis, Greece * Sa ...

Scandinavia
,
Siberia Siberia (; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a part of R ...

Siberia
; often treated as a variant of ''P. abies'' (and hybridises with it), but has distinct cones ** '''' – Serbian spruce,
Serbia Serbia (, ; Serbian Serbian may refer to: * someone or something related to Serbia, a country in Southeastern Europe * someone or something related to the Serbs, a South Slavic people * in both meanings, depending on the context, it may ref ...

Serbia
and
Bosnia Bosnia ( bs, Bosna / , ) is the north North is one of the four compass points The points of the compass are the vectors by which planet A planet is an astronomical body orbiting a star or Stellar evolution#Stellar remnants, stellar r ...

Bosnia
; local
endemic Endemism is the state of a species In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest gro ...
; important in horticulture ** ''
Picea pungens The blue spruce (''Picea pungens''), also commonly known as green spruce, white spruce, Colorado spruce, or Colorado blue spruce, is a species of Picea, spruce tree. It is native plant, native to North America, and is found in USDA Hardiness zone, ...

Picea pungens
'' – blue spruce or Colorado spruce,
Rocky Mountains The Rocky Mountains, also known as the Rockies, are a major mountain range A mountain range is a series of mountains ranged in a line and connected by high ground. A mountain system or mountain belt is a group of mountain ranges with simila ...

Rocky Mountains
, North America; important in horticulture ** '' Picea retroflexa'' – green dragon spruce, China ** ''
Picea rubens A spruce is a tree of the genus ''Picea'' , a genus of about 35 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal ecosystem, boreal (taiga) regions of the Earth. ''Picea'' is the sole genus ...

Picea rubens
'' – 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.


Morphology

Determining that a tree is a spruce is not difficult;
evergreen In botany Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Anc ...

evergreen
needles that are more or less quadrangled, and especially the
pulvinus 200px, Section through the pulvinus of '' Oxalis rosea'', from: Charles Darwin (1880): ''The Power of Movement in Plants">Charles_Darwin.html" ;"title="Oxalis rosea'', from: Charles Darwin">Oxalis rosea'', from: Charles Darwin (1880): ''The Power of ...

pulvinus
, 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.


Growth

Spruce seedlings are most susceptible immediately following
germination Germination is the process by which an organism In biology Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Biochemistry, chemical processes, Molecular biolog ...

germination
, 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.


Uses


Timber

Spruce 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.


Pulpwood

Spruce 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 medicine

The 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 .


Tonewood

Spruce 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 uses

The 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
North America North America is a continent A continent is any of several large landmasses. Generally identified by convention (norm), convention rather than any strict criteria, up to seven geographical regions are commonly regarded as continen ...

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. 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
Christmas tree A Christmas tree is a decorated tree, usually an evergreen In botany Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist ...

Christmas tree
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.


Diseases


''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 canker

A 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.


Predators

Small 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.


Pests

The (''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)
Results of spraying against spruce budworm in New Brunswick
Can. Dep. Agric., For. Biol. Div., Ottawa ON, Bi-mo. Progr. Rep. 10(1).
Population levels oscillate, sometimes reaching extreme outbreak levels that can cause extreme defoliation of and damage to spruce trees. To reduce destruction, there are multiple methods of control in place, including pesticides. Horntails, or Wood Wasps, use this tree for egg laying and the larvae will live in the outer inch of the tree under the bark. Spruce Beetles (Dendroctonus rufipennis) have destroyed swathes of spruce forest in western North America from Alaska to Wyoming.


Genome

The 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.


References


External links

*theplantlist.org
''Picea'' (Spruce)
*conifers.org
Gymnosperm Database - ''Picea''
*efloras.org
''Picea''
*pinetum.org / Arboretum de Villardebelle: Cones of selected species of ''Picea''

{{Authority control Picea,