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Timbers - Oak

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English name, Common Oak. Sessile Oak. (Common Oak also known as English Oak, German Oak, Sweden Oak, French Oak, Slovenian Oak or Polish Oak.).

Remarks, An important timber in constructional carpentry and joinery.

Family, Fagaceae.
Genus, Quercus.
Species, Quercus Robur. Quercus petraea.

Age, 500-800, some over 1000 years.

Height, 35m-45m.

Tree shape, Broadly spreading.

Leaf type, Deciduous.

Leaves shape, Elliptic to obovate, to 12cm long and 7.5cm wide, with three to six lobes on each side, dark green above , blue green beneath.

Flowering, April/May.

Flower colour, Male yellow green/Female inconspicuous.

Fruit, 3-4cm long, one third enclosed in cup.

Bark, Pale grey and fissured. Grey with longer straighter fissures.

Native region, Europe.

Natural habitat, Woods and hillsides.

Weight, Green 1050kg/m3. Air dried 750kg/m3.

Maturity, 15-20 years. Sometimes up to 50 years depending on whether growing in woodland or in the open.

Soil type, Rich, moderately moist, or dry soil.

Wood type, Hardwood.

Timber colour, Starts yellow brown to dark brown and greys with age.

Durability, Durable, (1 very durable, 2 durable, 3 moderately durable, 4 slightly durable, 5 not durable).

Treatable, Extremely difficult. (Easy, moderate easy, difficult, extremely difficult).

Moisture movement, Medium.

Texture, Medium to coarse.

Environmental, Not listed as an endangered species.

Availability, Readily available at good timber merchants.

Cost, High.

Chemical properties, Iron staining may occur in damp conditions, or when working on fresh timber with tools. Metal fixings can corrode. Also the tannin can stain hands blue/grey when working on fresh timber, can be very hard to remove.

Drying, Oak dries very slowly with a tendency to split and check, particularly in the early stages of drying. It is best not to force dry the timber with heating. A square section of 150mm can take 5-7 years to fully dry.

Working qualities, Working with hand or machine on the timber can be medium to hard. It will depend on weather the timber is green or dry. Green timber is easier to work on, but tools will stain the timber more, the dust will be less of a problem, which can be an irritant when dry. Working on dry timber can be very hard, tools will have to be sharpened more regular. Knots can cause problems when planing, they can come loose and block blades.
Timber should be pre-drilled when using nails or screws. Oak can be stained, waxed, polished or glued very well.

Uses, A highly valued timber used in many areas including heavy constructional carpentry and joinery, ship building, railway sleepers, mine props, flooring, furniture, tool handles, veneers and barrels for wine, whisky, bourbon, port, sherry and balsamico vinegar.

Information, Due to it's very high tannin content Oak does not need to be treated against decay or insect attack.
Up to 600 species of Oaks exist.
The sap wood of oak is very soft and very susceptible to decay and insect attack and also has no load bearing capabilities, so should never be used in construction work.
280 invertebrates species can live and feed on a mature Oak tree.
Both Common and Sessile Oak are native to Britain.
The easiest way to recognise Sessile Oak from Common Oak is the acorns are unstalked in the Sessile while the in the Common they are stalked.
Oak's are very drought resistant due to having mainly deep taps roots, which also anchor them to ground very well, and are less likely to suffer from uprooting in Winter storms, although dead limbs can be blown off.
Oak galls were used for centuries as the main ingredient in manuscript ink.
The bark has been used for tanning of leather.
The wood can be used to smoke cheese, fish or meat.