Picea mariana is a small, slow-growing conifer which produces tiny red cones during spring. The needles stay on the tree for years, although some insects (such as Spruce Sawflies) can defoliate the plant. This type of tree naturally lives in bogs, swamps, or mountains (hence some of its common names), and dominates portion of Alaska’s ecosystems.
Picea mariana (Black Spruce, Bog Spruce, Swamp Spruce
Family: Pinaceae
Subspecies: ‘Nana’ (dwarf to 60cm tall by 1m wide), may hybridize with P. rubens
Native: northern North America, primarily Canada
Hardiness Zones: 2-5
Height: to 15m (rarely 25m)
Diameter: to 3m (trunk to 25cm wide)
Root System: wide, shallow, rarely active past 60cm, adventitious growth up to 1m with rapid organic layer establishment
Growth Rate: slow
Age: typically to 100-200 years, record at 370
Deciduous: no
Monoecious/dioecious: monoecious
Tolerates: different soil types (deep humus, clays, loams, coarse till, and shallow soil mantles)
Problems (major): Performs poorly in hot, arid, and dry summers. Eastern-dwarf mistletoe, spruce worm, ground fires, and crown fires are potentially fatal. European, Yellowheaded, and Greenheaded Spruce Sawflies defoliate trees. These are extremely flammable, resulting in death if set alight.
Problems (minor): Monochamus Wood Borers can kill trees near recently logged areas with significant residual slash (uncommon)
Poisonous: no
Soil requirements: requires slightly acidic soils between 4.7-6.5 pH
Air Requirements: intolerant of air pollution
Watering requirement: moderate to high, typical to wetter regions such as boreal bogs
Sun requirement: full sun, mildly tolerant of partial shade
Leaves: light to moderate green needles, to 1.2cm long
Cones(male): red (turning yellow/brown and drooping), to 2 centimeters long
Cones (female): ovoid, to 3.1 centimeters, initially purple and erect, clustered at the tops of trees
Seeds require stratification: yes
Trunk: smooth, flaky
Form: very lean, conical, spire-like
Monoecious or Dioecious: monoecious
Notable characteristics:
Twigs are pubescent; the cones have toothed scale edges.
Uses:
Black Spruce are used for pulp, timber, beverages, medical salves, aromatic distillations, and as Christmas trees. It can be used as an ornamental or as a wind breaker in gardens because of its relatively minute size.
Sources used:
- Kershner, Bruce, Daniel Mathews, Gil Nelson, Richard Spellenberg, Terry Purinton, Andrew Block, Gerry Moore, and John W. Thieret. Field Guide to Trees of North America. Comp. Craig Tufts. New York: Sterling, 2008. Print.
- Andersson, F. A. Coniferous Forests, First Edition. N.p.: Elsevier Science, 2005. Print
- http://www.borealforest.org/trees/tree7.htm
- http://www.pfaf.org/user/Plant.aspx?LatinName=Picea+mariana
- http://plants.usda.gov/core/profile?symbol=pima
- http://plants.alaska.gov/pdf/Spellman%20et%20al%202014%20Invasive%20plants%20after%20fire%20in%20borealblack%20spruce.pdf
- http://web126.cc.utexas.edu/plants/result.php?id_plant=pima
- http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=260955&isprofile=0&
- http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=233500911
- http://www.na.fs.fed.us/pubs/silvics_manual/Volume_1/picea/mariana.htm
- http://www.fs.fed.us/database/feis/plants/tree/picmar/all.html
Immature female cones with their exotic color
Multiple mature P. mariana growing in a tiaga with their slender forms (uploaded from a Flickr bot on July 25, 2008)
Cones and foliage (uploaded by wikipdia user MPF on August 8, 2011)
I do not own the rights of these images; all credit goes to its original creator(s).
A Fascinating Green World 
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