wood is the hard fibrous lignified substance under the back of trees. Wood is one of materials used in production of various articles such as chairs, table, shelves etc others materials been metals, ceramics, plastics and Rubber.
There are two types of wood which are hard and soft wood.Hard wood comes from decidous trees and the trees from which hard wood is obtained tend to be slower growing and it is usually denser than soft wood. Others characteristics of hard wood is that,it grows in tropical region,it shed leaves every year and it always has a fat trunks. Examples of hard wood are iroko, mahogany,oak,afara etc.
Soft wood are woods derived from conifer and mostly grow in temperate region,it leaves are evergreen that is,it does not shed leave annually.softwood are flexible, lighter in weight and less dense.Examples of soft wood trees are spine, Christmas tree, spruce,fir etc.
There are four stages involved in wood processing which are tree felling, wood conversion,wood seasoning and wood preservation.Tree felling is just a way of cutting down the trees. Trees can be felled in Forest reserve or free zone. Forest reserve are government control area where there is form of restrictions by government on people because trees in this areas serves as a revenue generation to government covers,as such people can not go to this place to fell the trees except with permission from government. People were employed to monitor and arrested people who goes against government directive.
The second area where trees can be felled are free zones. Trees found in this place can be felled by individual without seeking government permission though government at any level always frowned at incessant felling of trees without replanting as this may lead to deforestation which has effect on ozone layer.
(1)The second stage in wood processing is wood conversion.This process follow tree felling.The felled trees is splitting into commercial marketable sizes. The felled tress that has been cut into logs will be transported from where it been cut to sawmill. Sawmill is a place where different saws are used to convert logs of wood into small sizes that people bought to produced various wood articles.There are different methods used in wood conversion such as quarter sawing method whereby the whole log is sawn into quarter shape before further cut into small sizes. Another method used in wood conversion is peeling or eccentric method.With this method the back of log will be steaming so as to soften the wood before it will be sliced into rectangular shape.
(2)The third stage in wood processing is wood seasoning. Seasoning of wood is the process of removing or reducing be the moisture or water content of wood in order to increase it useful life and prevent wood from damage. Seasoning of wood is very important as it improves load bearing properties, the wood becomes less dense as it looses moisture and chances of decay become minimal.
The are two methods of seasoning wood.Natural seasoning method,in this method the wood is stacked in order to allow air to dry the wood. This method is time consuming and it takes a lot of time before wood can be dried up but it is more economical and less expensive method as only air is what it takes to seasoning the timber. The second method of wood seasoning is artificial or kiln method.With this method the wet wood will be subjected to heating in order to remove the moisture. Advantage of this method over natural method is that,the drying rate can be controlled over natural method.
The last stage in wood production is wood preservation. Wood preservation entails application of chemicals to the wood to prevent insects attack and also to increased it useful live.Wood can be affected by wood boring bettle,termite and wood destroying fungi because of its organic chemical structure that is why it needs to be preserved in order to prevent damage from fungi and other insects like termite. Some of chemicals used in wood preservation are coal tar, creosote,paint and vanished,water repellant and stabilizers etc. Though most of these chemicals were designed for specific used.their applications is largely depends on particular need.
Wood defect is any features which can reduced economic value of wood in market. These defects can be natural or artificial. Natural defects are natural features that affect economic value of wood such as knot,while any defect occurs as a result of bad felling and insect attack are artificial defect.