What are the special features of spruce as a material?
Short symbol DIN EN 13556: PCAB
Botanical name: Picea abies (syn.: P. excelsa), family Pinaceae
Distribution: Central and Northern Europe, European Russia
Trade names: European spruce, Nordic spruce, red spruce, “red fir”, Baltic whitewood, spruce, Norway spruce (GB); épicea (FR); abete rosso (IT); vuren (NL)
The European spruce (Picea abies) has long been one of the most important German commercial tree species. It accounts for approx. 32% of the total forest area and is the most important supplier of wood for forestry. Other species of regional importance are the Serbian spruce (P. omorica), the Siberian spruce (P. ovata), the Himalayan spruce (P. smithiana) as well as the North American angelman spruce (P. engelmannii), white spruce (P. glauca) and black spruce (P. mariana).
Sapwood and heartwood are not distinguishable by colour. The wood is yellowish white and has a matt shine, darkening to yellowish brown under the influence of light. The regular alternation between light early wood and darker late wood results in clear grain on tangential surfaces and narrow stripes on radial surfaces. The small resin channels are only visible with a magnifying glass on smooth cross-sections. Fresh wood has a slightly resinous smell.
Straight grained, light-coloured softwood without heartwood colouring, clearly structured by dark late wood bands.
Strong rotary growth; compression wood (redwood); pine wood caused by resinification of the tissue; resin pockets; red colouring caused by fungal attack (red rot); hazel growth through fine-waved annual rings.
Spruce wood, after appropriate removal of any resin spots, can be treated well with any means and by any method, covering or glazing.
The wood of spruce is light, soft and relatively elastic and load-bearing. Both fresh and dry wood can be worked quickly and gently by machine and hand with all tools. It is also good for peeling and knives, provided the number and size of knots is small. The screw and nail strength is still satisfactory, gluing is problem-free.
The average shrinkage and swelling values result in good stability. Both natural and technical drying proceeds rapidly with a generally low tendency to cracking and deformation.
Areas of application
Spruce wood is offered as round timber, sawn timber, veneer as well as in the form of glued construction elements (solid structural timber, glued laminated timber). It is by far the most widely used building and construction timber in building construction and civil engineering, e.g. for roof-bearing and other structures in industrial, sports facility, hydraulic and bridge construction. In interior construction, spruce is versatile and can be used for skeletal structures, load-bearing walls and ceilings, floors, staircase, wall and ceiling panelling, built-in furniture, sauna construction, etc., and outdoors for façade panelling, balconies, windows and doors, fences and gates. Furthermore, spruce is the most important bulk wood for pallets, many wood-based materials and for the pulp and paper industry. Uniformly grown, fine-grained and knot-free spruce wood from high altitudes in the low mountain ranges and the Alps (approx. from 600 to 700 m) is the world’s preferred and almost exclusively used resonance wood for tops and backs of string and keyboard instruments with a demanding sound.
After prolonged water storage, bacterial attack can cause uneven absorption of the surface treatment agents and thus staining; the technical usability of the wood is not affected by this. The resistance of spruce wood to weak alkalis and acids is relatively high.
Spruce – Technical Properties
Weight fresh700-850 kg/m³
Weight air-dry430-470 kg/m³
Compressive strength u12-1540-50 N/mm²
Flexural strength u12-1565-77 N/mm²
Modulus of elasticity (bending) u12-1510000-12000 N/mm²
Hardness (JANKA) ⊥, converted1.5-2.8 kN
Hardness (BRINELL) ⊥ to fiber u12-1512-16 N/mm²
Differential shrinkage (radial)0.15-0.19 %
Differential shrinkage (tangential)0,27-0,36 %
Natural durability (DIN-EN 350-2)4