FURNITURE GYAAN: Wood

Wood is an organic material, a natural composite of cellulose fibers (which are strong in tension) embedded in a matrix of lignin which resists compression. In the strict sense wood is produced as secondary xylem in the stems of trees (and other woody plants). In a living tree it transfers water and nutrients to the leaves and other growing tissues, and has a support function, enabling woody plants to reach large sizes or to stand up for themselves. Wood may also refer to other plant materials with comparable properties, and to material engineered from wood, or wood chips or fiber.
People have used wood for millennia for many purposes, primarily as a fuel or as a construction material for making houses, tools, weapons, furniture, packaging, artworks, and paper. Wood can be dated by carbon dating and in some species by dendrochronology to make inferences about when a wooden object was created. The year-to-year variation in tree-ring widths and isotopic abundances gives clues to the prevailing climate at that time.

Types Of Wood :
Hardwoods :
Hardwood is wood from angiosperm trees (more strictly speaking non-monocot angiosperm trees). It may also be used for those trees themselves: these are usually broad-leaved; in temperate and boreal latitudes they are mostly deciduous, but in tropics and subtropics mostly evergreen.
Hardwood contrasts with softwood which comes from conifer trees, which usually are not broad-leaved. Hardwoods are not necessarily harder than softwoods. In both groups there is an enormous variation in actual wood hardness, with the range in density in hardwoods completely including that of softwoods; some hardwoods (e.g. balsa) are softer than most softwoods, while yew is an example of a hard softwood. The hardest hardwoods are much harder than any softwood. There are about a hundred times as many hardwoods as softwoods.

Structure

SEM images showing the presence of pores in hardwoods (Oak, top) and absence in softwoods (Pine, bottom)

Hardwoods have a more complex structure than softwoods. The dominant feature separating "hardwoods" from softwoods is the presence of pores, or vessels^[1]. The vessels may show considerable variation in size, shape of perforation plates (simple, scalariform, reticulate, foraminate), and structure of cell wall (e.g. spiral thickenings).

Applications:
Hardwoods are employed in a large range of applications including: construction, furniture, flooring, cooking, utensils, etc. Solid hardwood joinery tends to be expensive compared to softwood. In the past, tropical hardwoods were easily available but the supply of some species such as Burma teak and mahogany is now becoming restricted due to over-exploitation. Cheaper "hardwood" doors, for instance, now consist of a thin veneer bonded to a core of softwood, plywood or medium-density fibreboard (MDF). Hardwoods can also be used in a variety of objects but mainly for furniture or musical instruments because of their density. Different species of hardwood lend themselves to different end uses or construction processes. This is due to the variety of characteristics apparent in different timbers including, density, grain, pore size, growth pattern, wood fibre pattern, flexibility and ability to be steam bent. For example, the interlocked grain of elm wood makes it suitable for the making of chair seats where the driving in of legs and other components can cause splitting in other woods.

Cooking:

There is a correlation between density and calories/volume. This makes the denser hardwoods such as oak, cherry, and apple more suited for camp fires, cooking fires, and smoking meat as they tend to burn hotter and longer than softwoods such as pine or cedar.

Softwood

The term softwood is used to describe wood from conifers. It may also be used to describe these trees, which tend to be evergreen, notable exceptions being bald cypress and the larches.
Softwood is the source of about 80% of the world's production of timber, with traditional centers of production being the Baltic region (including Scandinavia and Russia) and North America. The term softwood is used as opposed to hardwood, which is the wood from angiosperm trees. Softwoods are not necessarily softer than hardwoods. In both groups there is an enormous variation in actual wood hardness, with the range in density in hardwoods completely including that of softwoods; some hardwoods (e.g. balsa) are softer than most softwoods, while the hardest hardwoods are much harder than any softwood; this is not surprising as there are about a hundred times as many hardwoods as there are softwoods. The woods of longleaf pine, douglas fir, and yew are much harder in the mechanical sense than several hardwoods.

Applications:

In general softwood is easy to work: it forms the bulk of wood used by humans.