Norway spruce

Norway spruce
Picea abies

Reader's Digest logo

Norway spruce belongs to the scientific genus Picea and is a member of the pine family (Pinaceae).

Norway spruce (Picea abies) is a conifer species growing to over 45m and flowering in May.

Lifespan: In its native region Norway spruce has reached up to 1000 years.

 

Characteristics

Bark is copper-brown, appears smooth but is rough with papery scales. Mature trees have dark purplish bark, cracked into small plates. Branches are in regular horizontal whirls ascending towards the crown to form a strong conical silhouette. Twigs are orange-brown, grooved and slightly hairy. Terminal buds are dark brown, oval (55mm).

Spruces all have a woody peg at the base of every needle which is a useful identification aid. Needles are 1.5cm, stiff, four-sided, pointed, dark green with fine white speckled lines. Needles grow on all sides of the shoot; the upper needles point forward, needles beneath part to reveal the twig.

Norway spruce is monoecious: both male and female flowers are found on the same tree. Male flowers are 1cm, crimson, oval clusters of stamens that turn yellow in spring when laden with pollen. Female flowers are dark red, upright and oval, often crowded toward the top of the tree. Norway spruce is wind pollinated.

The fertilised female flowers ripen during summer, turning green, enlarge rapidly, bending over to become pendulous, red-brown cones (12–15cm) with regular diamond-shaped, round-edged scales. In spring they release seeds: two per scale, each attached to a papery wing.

Norway spruce

Norway spruce cones

Norway spruce needles

Distribution

Native to mountain areas of Europe from the Pyrenees, Alps, Balkans and Carpathians, north into Scandinavia and as far east as western Russia.

Norway spruce is a high mountain species in central Europe but in the colder climate of northern Europe it is found in lowland areas.

Norway spruce was thought to be a native species of the UK in the last interglacial period. Written records show it was re-introduced and growing back in the UK as early as 1548. From the 1800s it was a principal timber-producing species; later displaced by Sitka spruce, it now only represents 5% of the total conifer area in the UK.

Human value

Timber is pale cream; often called ‘whitewood’ with no colour difference between heartwood and sapwood, and only a subtle difference between the pale spring wood and darker summer wood in each annual ring. It has a straight grain and a fine texture, is moderately strong (similar to Scots pine) and easily worked. It has no natural durability but the sapwood takes preservatives, so can be used for external joinery. It is commonly used in buildings for joists, rafters and flooring, for furniture and box making, for chipboard and paper pulp.

As well as being widely planted for timber the Norway spruce has traditionally been used as a Christmas tree in the UK since the mid-19th century. The tradition of a Christmas tree was first introduced by members of the Royal family in the early 1800s and the custom gradually spread among the general population.

In the past, Norway spruce resin was used as a source of turpentine and pitch and its fresh shoots were used for making spruce beer.

Norway spruce female flowers

Norway spruce male flowers

Norway spruce cones

Wildlife value

Research has shown that planted Norway spruce stands in the UK have similar species richness to native stands and support hundreds of species of invertebrates including beetles, weevils, ground beetles, hoverflies, deadwood specialist insects and moths such as the spruce carpet moth, the cloaked pug, the dwarf pug and the barred red.

Norway spruce cones are an important source of food for red squirrels. The more regular coning in spruce forests compared to pine has helped boost some red squirrel reserves in northern England and Scotland.

In Norway, Denmark and Sweden, Norway spruce is found growing in natural association with birch and Scots pine and, in other parts of Europe, alongside beech and silver fir. It therefore has a natural place in mixture with broadleaf species.

Management

Norway spruce is an early successional species that is moderately shade tolerant. Early growth is slow, making it a good conifer to plant in mixture with broadleaf trees.

It grows best on very deep, moist to well-drained soils of medium to high fertility. Serious drought conditions can lead to crown dieback where the whole tree may discolour, turning brown evenly all over. On heather-rich sites Norway spruce is unable to compete for nitrogen and on calcareous sites this species may suffer from chlorosis (lack of chlorophyll) caused by nutrient deficiency.

Norway spruce is cold hardy but vulnerable to late spring frosts and does not tolerate pollution or salt. It suffers from exposure and is therefore more suited to lower slopes and valley bottoms where there is less risk of frost damage or wind throw.

Viable seed is rarely produced in any quantity in the UK. Temperature plays a big role in seed development and maturation, so seed crops are rare and irregular in the far north and at high altitudes. Seeds usually ripen in October and are dispersed naturally through until April. Seeds can be sown mid to late March and do not require pre-treatment unless they are dormant. When sourcing, seeds of eastern European provenance are generally preferable.

Norway spruce suffers from a disorder known as top-dying or sub-top dying. Current thinking is that this is caused by physiological drought or desiccation due to warm airflow over the tree during mild UK winters. This increases transpiration at a time when the roots are less effective at replacing moisture. Visual symptoms are a loss of leader length and the whirl of branches below the leader showing browning (sometime referred to as spruce reddening). It can be a common problem and a significant cause of decline and death in the UK as the tree is adapted to colder, drier continental climates.

Norway spruce can be susceptible to Green spruce aphid (Elatobium) although less commonly than Sitka spruce.

Norway spruce is highly susceptible to fungi such as Stereum, which enter via wounds and degrade timber; care must be taken during extraction and thinning. It can also be affected by Heterobasidion (Fomes root and butt rot).

In wider Europe, the larger European spruce bark beetle (Ips typographus) is a significant pest.

Norway spruce flowers

Norway spruce

Illustrations © Reader’s Digest Association, Inc.

Norway spruce needles © Debbie Cotton.
Other photographs © Forestry Commission.