Spruces are evergreen coniferous trees that belongs to the family Pinaceae.
There are about 35 species of spruce in the world.
These needled evergreens typically perform best in a site offering full sun, acidic soil and good drainage but don’t grow well in clay soil.
Spruces are large trees and most species grow to the height of 20 to 60 meters (60 to 200 feet). The Sitka spruce is the tallest species of spruce that can reach almost 100 meters (330 feet) in height.
For most of the common spruces, you can expect 150 – 200 year lifespan on average – though some have lived far longer – 800 or 900 years is not unheard of.
In the mountains of western Sweden scientists have found a Norway spruce tree, nicknamed Old Tjikko [photo below], which by reproducing through layering has reached an age of 9,550 years and is claimed to be the world’s oldest known living tree.
Spruces are pyramidal trees with whorled branches and thin, scaly bark.
The needles of spruce trees are attached singly to the branches in a spiral fashion, each needle on a small peg-like structure.
The needles are shed when 4–10 years old, leaving the branches rough with the retained pegs (an easy means of distinguishing them from other similar genera, where the branches are fairly smooth).
Each spruce tree carries male and female cones. The larger female cones contain ovules, which develop into egg cells, or female gametophytes. To reproduce, the smaller male cones let loose grains of pollen, which are the male gametophytes. The pollen travels on the breeze to fertilize the egg cells in the female cones. This produces an embryo protected by a seed coating, but the process of ripening takes about three years. After that, the cone opens up to release the seed.
Spruce produce resin that flows from the injured bark. Unfortunately, resin is highly flammable and it facilitates spreading of the forest fire.
Spruce is useful as a building 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 Flyer, was built of spruce.
Spruce is the standard material used in soundboards for many musical instruments, including guitars, mandolins, cellos, violins, and the soundboard at the heart of a piano and the harp.
Spruce is one of the most important woods for paper uses, as it has long wood fibres which bind together to make strong paper.
Spruces are popular ornamental trees in horticulture, admired for their evergreen, symmetrical narrow-conic growth habit. For the same reason, some (particularly Norway spruce and Serbian Spruce) are also extensively used as Christmas trees.
Spruces are excellent for individual planting or as windbreaks and shelterbelts.
In the landscape, spruce trees usually require minimal pruning and grow in a variety of colors, including yellow and silvery blue.
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 (a disease resulting from a lack of vitamin C) in his crew.
The leaves and branches, or the essential oils, can be used to brew spruce beer.
The tips from the needles can be used to make spruce tip syrup.
In survival situations spruce needles can be directly ingested or boiled into a tea.
The resin was used in the manufacture of pitch in the past (before the use of petrochemicals).
Native Americans in North America use the thin, pliable roots of some species for weaving baskets and for sewing together pieces of birch bark for canoes.
Spruce trees are mythologically important plants among Southwestern tribes of Native Americans, where they are symbols of the sky and directional guardians of the north. According to Hopi myth, the spruce tree was once a medicine man, Salavi, who transformed himself into a tree. For this reason, spruce trees are considered particularly sacred to the Hopis, who use spruce boughs to adorn kachina dancers.
Spruce tree is a symbol of nobility, generosity and peace.
The word ‘spruce’ is derived from the French word ‘Pruce’ meaning Prussia, from where these trees are believed to have originated.
Several species of spruce are enlisted as threatened species by the International Union for Conservation of Nature (IUCN).