Spruce

Spruce is any of the large, coniferous tree species belonging to the genus Picea of the family Pinaceae, distributed across the temperate and boreal regions in the Northern Hemisphere. These trees can be identified by the four-sided needles and the cones that hang downwards after pollination.

Scientific Classification
Kingdom	Plantae
Clade	Tracheophytes
Division	Pinophyta
Class	Pinopsida
Order	Pinales
Family	Pinaceae
Subfamily	Piceoideae
Genus	Picea

List of Different Types of Spruce Trees

The Picea genus includes thirty-five extant species, out of which the Brewer’s spruce has a basal position, after that come the Sitka spruce, and then the other species. All these species are classified into three clades, as given below.

Clade I

• Brewer’s spruce (Picea breweriana)
• Sitka spruce (Picea sitchensis)
• Engelmann spruce (Picea engelmannii)
• White spruce (Picea glauca)

Clade II

• Sargent’s spruce (Picea brachytyla)
• Chihuahua spruce (Picea chihuahuana)
• Burmese spruce (Picea farreri)
• Likiang spruce (Picea likiangensis)
• Martinez spruce (Picea martinezii)
• Maximowicz spruce (Picea maximowiczii)
• Taiwan spruce (Picea morrisonicola)
• Veitch’s spruce (Picea neoveitchii)
• Caucasian or Oriental spruce (Picea orientalis)
• Purple cone spruce (Picea purpurea)
• Schrenk’s spruce (Picea schrenkiana)
• Morinda spruce (Picea smithiana)
• Sikkim spruce (Picea spinulosa)
• Tiger-tail spruce (Picea torano)
• Wilson’s spruce (Picea wilsonii)

Clade III

• Norway spruce (Picea abies)
• Alcock’s spruce (Picea alcoquiana)
• Dragon spruce (Picea asperata)
• Qinghai spruce (Picea crassifolia)
• Glehn’s spruce (Picea glehnii)
• Jezo spruce (Picea jezoensis)
• Korean spruce (Picea koraiensis)
• Koyama’s spruce (Picea koyamae)
• Black spruce (Picea mariana)
• Meyer’s spruce (Picea meyeri)
• Siberian spruce (Picea obovata)
• Serbian spruce (Picea omorika)
• Colorado spruce or blue spruce (Picea pungens)
• Green dragon spruce (Picea retroflexa)
• Red spruce (Picea rubens)

In addition to these spruce species, several cultivars exist including ‘Dwarf Alberta Spruce’, ‘Black Hills Spruce’, ‘Coerulea’, ‘Echiniformis’, ‘Jean’s Dilly’, ‘Pendula’, ‘Pixie’, and ‘Rainbow’s End’.

Quick Information
Tree Type	Evergreen coniferous
Identification	Height: 60-200 ft Leaves: Linear, spirally-arranged, needle-like, about 1 inch long Trunk Diameter: 0.5-2 ft Bark: Thin, scaly, gray to reddish-brown Female Cones: Drooping, ovoid or cylindrical, green to purple when young, pale to dark brown when matured Seeds: Winged, with 5-10 cotyledons Branches: Whorled Crown: Conical to spirelike Pollen cones: Single/grouped, oblong, auxiliary, yellow to purple
Distribution	Western and Northern North America, Mexico, Europe, Asia
Habitat	Mountainous regions, boreal forests
USDA Hardiness Zone	2-8
Growth Rate	Fast, 30-60 inches annually
Lifespan	Long-lived, varies depending on the species, some can live for 1000 years
Growing Conditions	Sunlight: Prefers full sun, but also tolerates shade Soil: Loam, sandy, clay, well-drained Water: 1-3 inches every week when rainfall is low
Drought Tolerance	Moderate
Diseases & Pests	Shoot blight, needle cast, and stem canker caused by the fungi Sirococcus, Rhizosphaera kalkhoffi, and Valsa kunzei respectively, eastern spruce budworm is a pest of white and black spruce
Reproductive System	Monoecious
Propagation	From stem cuttings
Wildlife Value	Deer mice, mountain voles, chipmunks, and red-backed vole eat spruce seeds, red squirrels feed on its flower buds
Uses	As pulpwood for making paper, building wood, tonewood for mandolins, guitars, violins, pianos, and cellos, ornamental Christmas trees; shoots are the source of vitamin C, for making spruce beer from branches and leaves
IUCN Conservation Status	Species like Norway spruce, blue spruce, and white spruce are listed as Least Concern, while Serbian spruce is considered Endangered

Interesting Facts

• The spruce tree is symbolically used in the coat-of-arms of the Finnish town of Kuhmo.
• Spruce needles fall off when the tree is 4-10 years old. However, the peg-like structures (called sterigmata or pulvini) on the branches are retained, making them rough.
• The Wright brothers constructed the first aircraft, called Wright Flyer, using spruce wood.
• Captain Cook prepared an alcoholic sugar-based beer from branches, needles, and buds of spruce trees during his voyages and gave it to his crew for preventing scurvy.
• A Norway spruce named Old Tjikko is the oldest clonal tree, having an age of 9,550 years.

References

1. https://oregonstate.edu/trees/ conifer_genera/spruce.html
2. https://www.conifers.org/ pi/Picea.php
3. http://biorefinery.utk.edu/ technical_reviews/Tree%20Size.pdf
4. http://hort.uconn.edu/ detail.php?pid=310
5. https://web.archive.org/web/ 20040405082131/http:// www.nasm.si.edu/ exhibitions/gal100/wright1903.html