Common Name: Sitka Spruce

General Information

Picea sitchensis is an evergreen tree that can grow up to 50 metres tall.
This species is a highly valuable timber tree, harvested from the wild and cultivated plantations in large quantities for commercial use. The plant also has a wide range of traditional uses as a food, medicine and source of materials and is sometimes grown as an ornamental.
Picea sitchensis still covers vast tracts of coastal mainland and islands along the Pacific Coast of North America; it is also a pioneer after disturbance, either natural or from logging, and will return unless deliberately prevented. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2013)[].

Known Hazards

None known

Botanical References

,

Range

Western N. America - Alaska, British Colombia, Washington, Oregon, N. California.

Habitat

Moist, sandy, often swampy soils, occasionally on wet rocky slopes in the far north of its range[]. Alluvial soils from sea level to 300 metres, usually close to the coast[].

Properties

Conservation Status	Least Concern
Edibility Rating
Medicinal Rating
Habit	Evergreen Tree
Height	50.00 m
Growth Rate	Fast
Pollinators	Wind
Cultivation Status	Wild

Cultivation Details

Picea sitchensis occurs from tidewater up to steep mountain sides in Alaska and British Columbia, generally to ca. 900 m a.s.l. (highest record 1,189 m), always in proximity to oceanic weather. The soils are variable, usually with a thick humus layer. The climate is very humid, annual precipitation ranges from 1300 mm to 3750 mm, the winters are moderate (in coastal Alaska snow in winter usually stays only above 200 m)[].
Likes abundant moisture at the roots, if grown in drier areas it must be given a deep moist soil[]. Tolerates poor peaty soils[]. Succeeds in wet, cold, poor and shallow soils[]. Trees have succeeded on pure chalk when on a north facing hollow deep in beech woods[]. Prefers a pH between 4 to 6[]. Dislikes shade[]. Intolerant of atmospheric pollution[]. Very tolerant of exposure[], resisting salt laden gales[], though trees are not very wind firm in shallow soils[].
A long-lived tree, with specimens 700 - 800 years old being recorded[]. It is slow growing for its first two or three years, though it soon becomes an extremely fast growing tree and is very widely planted for timber in Britain and other temperate areas[, ]. Even trees 30 metres tall are increasing in height by 1 metre a year[]. New growth takes place from May to July or August and some very vigorous trees will produce a second flush of growth until September[]. Although the dormant tree is very cold-hardy, growth can be severely checked if the trees are growing in a frost hollow, because the young shoots are very susceptible to damage by late frosts[, ]. In Britain the best stands are produced in the sheltered valleys of W. Scotland. Trees are unsurpassed for rapid volume wood production in cool wet mountain sites on blanket peat in W. Britain[]. In areas with cool wet summers (1200mm of rain per year) it makes a huge specimen tree[].
Trees should be planted into their permanent positions when they are quite small, between 30 and 90cm[, ]. Larger trees will check badly and hardly put on any growth for several years. This also badly affects root development and wind resistance[].
In some upland areas, especially over granitic or other base-poor soils, growth rate and health have been seriously affected by aluminium poisoning induced by acid rain[].
Plants are strongly outbreeding, self-fertilized seed usually grows poorly[]. They hybridize freely with other members of this genus[]. Many trees do not bear female flowers in most years.
Subject to damage by the green spruce aphid[], trees are also often attacked by a bark beetle and so should be kept away from more valuable plantings[]. A biological control for the bark beetle is being introduced (1990)[].

Edible Uses

Young shoots - raw[, ].

Young male catkins - raw or cooked. Used as a flavouring[].
Immature female cones - cooked. The central portion, when roasted, is sweet and syrupy[]. The cones are 6 - 10cm long[].

Inner bark - raw or cooked[]. It can be dried, ground into a powder and then used as a thickener in soups etc or added to cereals when making bread[]. The inner bark was usually harvested in the spring, though it was also sometimes taken in the summer[]. An emergency food, it is only used when all else fails.

Seed - raw[]. The seed is about 2 - 4mm long[]. It is rich in fats and has a pleasant slightly resinous flavour but is too small and fiddly to be worthwhile unless you are desperate[, ].

A refreshing tea, rich in vitamin C, can be made from the young shoot tips[].

A gum obtained from the bark is hardened in cold water and then used for chewing[, , ]. It should be aged for 3 days or more before using it. The best gum is obtained from the southern side of the tree.

Medicinal

Sitka spruce was widely employed medicinally by several native North American Indian tribes who used it especially for its antiseptic and pectoral qualities in the treatment of lung complaints, wounds, sores etc[]. It is little, if at all, used in modern herbalism.

The inner bark is laxative[, ]. It has been chewed in the treatment of throat problems, coughs and colds[].
A decoction of the branch tips and the bark has been used in the treatment of rheumatism, stomach pains, constipation and gonorrhoea[].

A decoction of the cones has been taken in the treatment of pain[]. The cones have also been used in steam baths to treat rheumatism[].

A decoction of the bark has been used as a steam bath in the treatment of back aches[].

The resin is antiseptic and diuretic[]. A decoction has been used in the treatment of gonorrhoea[]. A poultice of the resin has been used as a rub on rheumatic joints[]. Combined with Indian Hellebore roots (Veratrum viride), it has been used as a poultice on rheumatic joints[]. The resin has also been used as a dressing or poultice on cuts, broken skin, boils, wounds, infections and suppurating sores[]. The resin has been chewed as a breath freshener and as a treatment for TB[].

The gum from new shoots and small branches has been placed in the eyes as a treatment for snow blindness[].

A decoction of the roots has been used in the treatment of diarrhoea[].

Other Uses

The tough and flexible root is used in basket making and as a string[, ]. The roots were burnt over an open fire to remove the bark, then they were dried and split to make hats, ropes etc[]. The main body material of baskets was made from the roots. These were cut into lengths 75 - 90cm long and 12 - 25mm in diameter. Whilst still full of sap and soft, these were split into broad flat bands and these in turn were sub-divided by knife and teeth until the desired size was obtained - a little larger than coarse thread, about like small twine. The vertical rods were made of hazel (Corylus spp) and the overlay was bear grass (Xerophyllum tenax)[].

The roots were used by several native North American Indian tribes to make tightly woven baskets that would hold water[].

The limbs and roots can be pounded, shredded and used to make ropes[].

A pitch is obtained from the tree and is used for caulking boats, waterproofing boxes etc[, ].
The rendered pitch has been used as a glue[]. The pitch can be melted then used as a protective varnish-like coat on wood[].

Wood - strong according to some reports[, ], not strong according to others[, , ]. The quality of the wood for aircraft construction is unsurpassed, it is remarkably strong yet light and its resistance - weight ratio is among the highest[]. The wood is elastic, soft, light, straight grained. Equal in quality to P. abies but more quickly produced, the wood is used for shipbuilding, construction, packing cases, doors, posts etc[, , , ]. The wood is also valued for making musical instruments[] and is widely used in the pulp industry to make paper[].
Smaller sizes go to the paper industry, but big trees are prized for construction and special uses such as small aircraft, masts and spars for sailing ships, oars for rowing boats, ladders, and sounding boards of musical instruments[].
The wood is a good fuel, knotted bits of wood would keep the fire burning all night[].

Propagation

Seed - stratification will probably improve germination so sow fresh seed in the autumn in a cold frame if possible[]. Sow stored seed as early in the year as possible in a cold frame[]. A position in light shade is probably best[]. Seed should not be allowed to dry out and should be stored in a cool place[]. Prick out the seedlings into individual pots when they are large enough to handle and grow them on in the greenhouse or cold frame for their first winter. They can be planted out into their permanent positions in early summer of the following year, or be placed in an outdoor nursery bed for a year or so to increase in size. They might need protection from spring frosts.
Cuttings of semi-ripe terminal shoots, 5 - 8cm long, August in a frame. Protect from frost. Forms roots in the spring[].
Cuttings of mature terminal shoots, 5 - 10cm long, September/early autumn in a cold frame. Takes 12 months[].
Cuttings of soft to semi-ripe wood, early summer in a frame. Slow but sure.