Oak is found both in this country and also in America, Holland, and the Baltic.

British Oak is found in three principal varieties1 which need not be described in detail.

It is in section of a light brown colour, with a hard surface, narrow and regular annual rings, and clearly-marked medullary rays.

The timber is very strong, hard, tough, and durable ; is used for all purposes where strength and durability are required in engineering structures, and in buildings for sills, treads, superior joinery, keys, wedges, etc.

American Oak2 has a straighter and coarser grain than English oak, but is not so strong or durable.

Dantzic, Riga, and Italian Oaks are chiefly used for ship-building. French Oak is very like British oak.

Wainscot is a form of oak that comes chiefly from Holland and Riga, is easily worked, and is so converted as to show the silver grain.

Beech is of a whitish-brown colour, with very distinct medullary rays and perceptible annual rings. The wood is hard, compact, and smooth, not difficult to work, very durable if always dry or always submerged, but decays quickly under alternate wet and dry or in damp places. It is used chiefly for piles, wedges, and carpenters' tools.

Ash is of a brownish-white, with yellow streaks, each annual layer separated from the next by a ring of pores. The sapwood is not generally distinguishable. The timber is tough, flexible, and durable when dry. It is too flexible for building purposes, and is used chiefly for tool handles and felloes and spokes of wheels.

Elm is found in several varieties. The heartwood is reddish-brown and the sapwood yellowish. No medullary rays visible. The wood is very fibrous, dense and tough, durable - the sapwood as well as the heartwood, except when alternately wet and dry. It is very useful for work under water, such as piles, and for various carpenters' purposes.

Mahogany is imported chiefly of two descriptions, Honduras or Bay Mahogany and Spanish Mahogany, the latter from Cuba.

The wood is of a golden-brown colour, often very veined and mottled, capable of receiving a good polish, and durable when dry and not exposed to weather. The Spanish is distinguished from the Honduras by a chalk-like substance in its pores. Both descriptions are used for handrails and furniture.

1 Stalk-fruited or Old English Oak, Quercus robur or Quercus pedunculata. Cluster-fruited or Bay oak, Quercus sessiliflora. Durmast oak, Quercus pubescens.

2 White oak (Quercus alba) or pasture oak. Other kinds are also imported.

Teak or Indian Oak comes chiefly from Burmah. It somewhat resembles English oak, but has no visible medullary rays. It is stronger and stiffer, but splinters easily. It contains an aromatic resinous oil, which makes it very durable.

This timber is too expensive for general use in buildings, but is sometimes employed for treads of steps, floors, etc.

Greenheart comes from South America. Its section is full of pores like that of a cane, of a dark green colour, the sapwood not distinguishable from the heart, and the annual rings not perceptible.

It is the strongest timber in use, and contains an essential oil which preserves it for a time from the attacks of worms. These qualities make it very valuable for marine work, in which it is much used.

Seasoning

Timber is best seasoned, and the sap dried up, by being stacked under cover with the air circulating freely round it. There are methods of seasoning by hot air, also by boiling and steaming, and other special processes, which cannot here be described.

Decay

When timber is in positions where it is alternately wet and dry, or not well ventilated, it soon decays, the sapwood being generally the first affected.

Dry Rot takes place in confined positions. A fungus eats into the timber, makes it change colour, smell disagreeably, become brittle, and eventually reduces the fibres to powder.

Wet Rot occurs in the growing tree, and in positions where the gases generated can escape.

Preservation

The best method of preserving timber from decay is to have it thoroughly seasoned and placed in well-ventilated positions.

Painting or Charring preserve timber if it is thoroughly seasoned ; if not, they do harm by confining the moisture and causing rot.

Greosoting consists in forcing creosote (oil of tar)l into the pores of the timber, by which the albumen of the wood is coagulated, worms repelled, and rot prevented.

There are many other methods of preserving timber, which are described in Part III.

Felling Timber

The best season for felling timber is at midsummer or midwinter in temperate, or during the dry season in tropical climates, when the sap is at rest.

The age at which a tree should be felled varies with circumstances. The heartwood must be fully formed, but the tree must not have passed its maturity, which will be shown by the presence of young shoots and vigorous top-branches.