Picea mariana

{{Short description|North American species of spruce tree}} {{Speciesbox | name = Black spruce | image = Black spruce stand at Arctic Chalet, Inuvik, NT.jpg | image_caption = Stand of black spruce near [[Inuvik]], [[Northwest Territories]], Canada | status = LC | status_system = IUCN3.1 | status_ref = <ref name="iucn status 13 November 2021">{{cite iucn |author=Farjon, A. |date=2013 |title=''Picea mariana'' |volume=2013 |article-number=e.T42328A2972877 |doi=10.2305/IUCN.UK.2013-1.RLTS.T42328A2972877.en |access-date=13 November 2021}}</ref> | genus = Picea | species = mariana | authority = ([[Philip Miller|Mill.]]) Britton, Sterns & Poggenburg | range_map = Picea mariana levila.png | synonyms_ref = <ref>{{ThePlantList}}</ref> | synonyms = {{collapsible list|bullets = true |title=Synonymy |''Abies denticulata'' Michx. |''Abies mariana'' Mill. |''Abies nigra'' (Castigl.) Du Roi |''Peuce rubra'' Rich. |''Picea brevifolia'' Peck |''Picea ericoides'' Bean |''Picea nigra'' (Du Roi) Link |''Pinus denticulata'' (Michx) Muhl. |''Pinus mariana'' (Mill.) Du Roi |''Pinus marylandica'' Antoine |''Pinus nigra'' Aiton 1789 not J.F. Arnold 1785 }} }}

'''''Picea mariana''''', the '''black spruce''', is a North American [[species]] of [[spruce]] tree in the [[Pinaceae|pine family]]. It is widespread across Canada, found in all 10 provinces and all 3 [[Canadian Arctic Lands|territories]]. It is the official tree of [[Newfoundland and Labrador]] and is that province's most abundant tree. Its range extends into northern parts of the United States: in [[Alaska]], the [[Great Lakes region]], and the upper [[Northeastern United States|Northeast]]. It is a frequent part of the [[biome]] known as [[taiga]] or boreal forest.<ref name=farjon>{{cite book |last=Farjon |first=A. |date=1990 |title=Pinaceae. Drawings and Descriptions of the Genera |publisher=Koeltz Scientific Books |isbn=3-87429-298-3}}.</ref><ref name=rushforthc>{{cite book |last=Rushforth |first=K. |date=1987 |title=Conifers |publisher=Helm |isbn=0-7470-2801-X}}</ref><ref name=gd>{{Gymnosperm Database |family=Pinaceae |genus=Picea |species=mariana}}</ref><ref name=fna>{{eFloras|1|233500911|Picea mariana |family=Pinaceae |first=Ronald J. |last=Taylor}}</ref><ref>{{BONAP|ref|genus=Picea|species=mariana}}</ref>

The Latin [[binomial nomenclature|specific epithet]] ''mariana'' means "of the Virgin Mary".<ref name=RHSLG>{{cite book | last=Harrison |first=Lorraine | title=RHS Latin for Gardeners | year=2012 |publisher=Mitchell Beazley | location=United Kingdom | isbn=978-1-84533-731-5 }}</ref>

== Description == [[File:Picea mariana cones.jpg|left|thumb|Needles and young cones]] ''P. mariana'' is a slow-growing, small upright [[evergreen]] [[coniferous]] [[tree]] (rarely a [[shrub]]), having a straight trunk with little taper, a scruffy habit, and a narrow, pointed crown of short, compact, drooping branches with upturned tips. Through much of its range it averages {{convert|5|–|15|m|round=5|abbr=on}} tall with a trunk {{convert|15|–|50|cm|0|abbr=on}} diameter at maturity, though occasional specimens can reach {{convert|30|m|abbr=on}} tall and {{convert|60|cm|abbr=on}} diameter. The [[Bark (botany)|bark]] is thin, scaly, and greyish brown. The [[leaf|leaves]] are needle-like, {{convert|6|–|15|mm|frac=16|abbr=on}} long, stiff, four-sided, dark bluish green on the upper sides, paler [[glaucous]] green below. The [[Conifer cone|cones]] are the smallest of all of the spruces, {{convert|1.5|–|4|cm|frac=4|abbr=on}} long and {{convert|1|–|2|cm|frac=4|abbr=on}} broad, spindle-shaped to nearly round, dark purple ripening red-brown, produced in dense clusters in the upper crown, opening at maturity but persisting for several years.<ref name=farjon /><ref name=rushforthc />

Natural [[Hybrid (biology)|hybridization]] occurs regularly with the closely related ''[[Picea rubens|P. rubens]]'' (red spruce) and very rarely with ''[[Picea glauca|P. glauca]]'' (white spruce).<ref name=farjon /> It differs from ''P. glauca'' in having a dense cover of small hairs on the bark of young branch tips, an often darker reddish-brown bark, shorter needles, smaller and rounder cones, and a preference for wetter lowland areas. Numerous differences in details of its needle and [[pollen]] morphology also exist but require careful microscopic examination to detect. From true [[Fir|firs]], such as ''[[Abies balsamea]]'' (balsam fir), it differs in having pendulous cones, persistent woody leaf-bases, and four-angled needles, arranged all round the shoots.

Due to the large difference between [[heartwood]] and [[sapwood (wood)|sapwood]] moisture content, it is easy to distinguish these two wood characteristics in [[ultrasound]] images,<ref name="BlackSpruce">{{Cite journal | last1 = Wei | first1 = Q. | last2 = Chui | first2 = Y. H. | last3 = Leblon | first3 = B. | last4 = Zhang | first4 = S. Y. | title = Identification of selected internal wood characteristics in computed tomography images of black spruce: A comparison study | doi = 10.1007/s10086-008-1013-1 | journal = Journal of Wood Science | volume = 55 | issue = 3 | page = 175 | year = 2009 | s2cid = 135727845 | doi-access = free | bibcode = 2009JWSci..55..175W }}</ref> which are widely used as a [[Nondestructive testing|nondestructive technique]] to assess the internal condition of the tree and avoid useless log breakdown. Older [[Taxonomy (biology)|taxonomic]] synonyms include ''A. mariana'', ''P. brevifolia'', or ''P. nigra''.

== Ecology == Growth varies with site quality. In swamp and [[muskeg]] it shows progressively slower growth rates from the edges toward the centre. The roots are shallow and wide spreading, resulting in susceptibility to [[windthrow]]. In the northern part of its range, [[ice pruning|ice pruned]] asymmetric black spruce are often seen with diminished foliage on the windward side.<ref>{{cite web |first=C. Michael |last=Hogan |url=http://globaltwitcher.auderis.se/artspec_information.asp?thingid=44751 |title=Black Spruce: Picea mariana |website=GlobalTwitcher.com |editor-first=Nicklas |editor-last=Stromberg |date=2008 |archive-url=https://web.archive.org/web/20111005174426/http://globaltwitcher.auderis.se/artspec_information.asp?thingid=44751 |archive-date=2011-10-05 }}</ref> Tilted trees colloquially called "[[drunken trees]]" are associated with thawing of [[permafrost]].<ref name=farjon /><ref name=Kokelj>{{cite book |last=Kokelj |first=S.V. |title=Proceedings of the 8th Int'l Conf. on Permafrost |year=2003 |publisher=A.A. Balkema |location=Rotterdam |isbn=90-5809-582-7 |url=http://research.iarc.uaf.edu/NICOP/DVD/ICOP%202003%20Permafrost/Pdf/Chapter_100.pdf |author2=Burn, C.R. |editor=Marcia Phillips |editor2=Sarah Springman |editor3=Lukas Arenson |access-date=2 April 2013 |chapter='Drunken forest' and near-surface ground ice in Mackenzie Delta, Northwest Territories, Canada |archive-date=8 June 2015 |archive-url=https://web.archive.org/web/20150608164232/http://research.iarc.uaf.edu/NICOP/DVD/ICOP%202003%20Permafrost/Pdf/Chapter_100.pdf |url-status=dead }}</ref>

In the southern portion of its range it is found primarily on wet organic soils, but farther north its abundance on uplands increases. In the [[Great Lakes region]] it is most abundant in peat [[bogs]] and swamps, also on transitional sites between peatlands and uplands. In these areas it is rare on uplands, except in isolated areas of northern [[Minnesota]] and the [[Upper Peninsula of Michigan]].

[[File:Picea mariana taiga.jpg|thumb|left|Black spruce taiga, Copper River, Alaska]] Most stands are even-aged due to frequent fire intervals in black spruce forests. It commonly grows in pure stands on organic soils and in mixed stands on mineral soils. It is tolerant of nutrient-poor soils and is commonly found on poorly drained acidic peatlands. It is considered a [[climax species]] over most of its range; however, some ecologists question whether black spruce forests truly attain climax because fires usually occur at 50 to 150 year intervals, while "stable" conditions may not be attained for several hundred years.<ref name=farjon /> The frequent fire return interval, a natural [[fire ecology]], perpetuates numerous successional communities. Throughout [[Boreal ecosystem|boreal]] North America, ''[[Betula papyrifera]]'' (paper birch) and ''[[Populus tremuloides]]'' (quaking aspen) are successional hardwoods that frequently invade burns in black spruce. Black spruce typically seeds in promptly after fire and with the continued absence of fire eventually dominates the hardwoods.

Black spruce is a [[Pioneer species|pioneer]] that invades the [[sphagnum]] mat in filled-lake bogs, though often preceded slightly by ''[[Larix laricina]]'' (tamarack). Black spruce frequently out-competes shade-intolerant tamarack in the course of bog succession.<ref>{{cite journal |last=Conway|first=V.M| title=The bogs of central Minnesota|year=1949 |journal=Ecological Monographs|volume=19|issue=2|pages=173–206|doi=10.2307/1948637|jstor=1948637|bibcode=1949EcoM...19..173C }}</ref> However, as the peat soil is gradually elevated by the accumulation of organic matter and the fertility of the site improves, balsam fir and northern white cedar (''[[Thuja occidentalis]]'') eventually replace black spruce and tamarack. On drier sites following fires, black spruce can take over stands of faster growing [[jack pine]] (''Pinus banksiana'') by virtue of its ability to grow in partially shaded conditions which inhibit pine seedlings.<ref>{{cite book|last1=Kozlowski|first1=T.T.|last2=Ahlgren|first2=C.E.|title=Fire and Ecosystems|publisher=Academic Press|location=Cambridge Massachusetts|date=1974| isbn=978-0-12-424255-5|page=542}}</ref> But black spruce seedlings are intolerant to the low light and low moisture conditions under mature spruce stands. Balsam fir and northern white cedar, both more understory-tolerant species with deeper [[Taproot|taproots]], survive and eventually succeed the spruce in the absence of fire.<ref>{{cite journal|last=Bloomberg|first=W.J.|title=Fire and spruce|year=1950|journal=Forestry Chronicle|volume=26|issue=2|page=157|doi=10.5558/tfc26157-2|doi-access=free}}</ref>

The [[spruce budworm]], a [[moth]] larva, causes defoliation which kills trees if it occurs several years in a row, though black spruce is less susceptible than white spruce or balsam fir. Trees most at risk are those growing along with balsam fir and white spruce.<ref name="Saskatchewan2">{{Cite web |url=http://web.forestry.ubc.ca/fetch21/Z-PDF-pest-info-folder/Eastern%20spruce%20budworm.pdf |title=Forest Pest Fact Sheet |website=Saskatchewan Ministry of Environment |archive-url=https://web.archive.org/web/20180428134459/http://web.forestry.ubc.ca/fetch21/Z-PDF-pest-info-folder/Eastern%20spruce%20budworm.pdf |access-date=11 November 2017|archive-date=2018-04-28 }}</ref>

== Cultivation == Numerous [[cultivars]] have been selected for use in parks and gardens. The cultivar ''P. mariana'' 'Nana' is a dwarf form which has gained the [[Royal Horticultural Society]]'s [[Award of Garden Merit]].<ref name=RHS>{{cite web|title=Picea mariana 'Nana' AGM|url=https://www.rhs.org.uk/Plants/90319/Picea-mariana-Nana/Details|publisher=Royal Horticultural Society|access-date=2020-04-17}}</ref><ref>{{cite web | url = https://www.rhs.org.uk/plants/pdfs/agm-lists/agm-ornamentals.pdf | title = AGM Plants - Ornamental | date = July 2017 | page = 78 | publisher = Royal Horticultural Society | access-date = 25 April 2018}}</ref> Picea mariana is known to hybridize with Serbian spruce, ''[[Picea omorika]]''. The hybrid is ''[[Picea machala]]'', and hybrids with [[Sitka spruce]] are known as well.{{citation needed|date=March 2023}}

== Uses and symbolism == Black spruce is the [[Provincial tree emblems of Canada|provincial tree]] of [[Newfoundland and Labrador]]. The timber is of low value due to the small size of the trees, but it is an important source of [[pulpwood]] and the primary source of it in Canada.<ref name="Powers_Coniferous">{{cite book|last=Powers|first=R.F.|title=Coniferous Forests|year=2005|publisher=Elsevier|location=Amsterdam [u.a].|isbn=978-0-444-81627-6|page=271|edition=1st|author2=Adams, M.B. |author3=Joslin, J.D. |author4= Fisk, J.N. |editor=Andersson, F.|chapter=Non-Boreal Coniferous Forests of North America}}</ref> Fast-food [[chopsticks]] are often made from black spruce.<ref name="gd" /> It is increasingly being used for making [[cross laminated timber]] by companies such as Nordic Structures, which allows the high strength due to the tight growth rings to be assembled into larger timbers.<ref name="Chibougamou">{{cite web|title=BLACK SPRUCE'S UNIQUE FIBER|url=http://chibou.com/en/the-resource/black-spruce|website=Chantiers Chibougamou|access-date=31 October 2015}}</ref> Along with red spruce, it has also been used to make [[spruce gum]] and [[spruce beer]].<ref>{{cite book|last=Little|first=Elbert L.|title=The Audubon Society Field Guide to North American Trees: Eastern Region|publisher=Knopf|location=New York|year=1980|isbn=0-394-50760-6|page=284}}</ref>

== Gallery== <gallery> File:Small lake in the depths of the taïga.jpg|Boggy [[taiga]] habitat File:Spruce trees lit by midnight sun, Ivvavik National Park, YT.jpg|Lit by the midnight sun in [[Ivvavik National Park]] File:Picea mariana cones Ontario.jpg|Immature cones File:Picea mariana cone.JPG|Mature, open cones File:Picea mariana seeds.jpg|Seeds File:Black Spruce on a rainy autumn day in Abbot, ME, United States.jpg|alt=Black Spruce in fall|Black spruce in Abbot, Maine </gallery>

==References== {{Reflist}} {{Commons category-inline|Picea mariana|''Picea mariana''}}

[[Category:Least concern flora of the United States]] [[Category:Least concern plants]] [[Category:Picea|mariana]] [[Category:Trees of Northern America]] [[Category:Plants described in 1768]] [[Category:Provincial symbols of Newfoundland and Labrador]] [[Category:Trees of continental subarctic climate]]