Lumber, which is also often called timber in the USA, is a selection of wood in any of its pre and post processing stages. It includes all wood from the moment of felling to the time it is ready for use in whatever industry it is needed (mainly the building, furniture and paper manufacturing industry). Lumber is not limited to a single type or species of wood, but most hardwoods are preferred over the softwood from coniferous species such as pine, fir and spruce. However, some softwood’s are used to manufacturer and build high-grade flooring.
Regional uses of the word lumber
In most Commonwealth Countries such as the UK, Australia, New Zealand and South Africa the term Lumber is used to refer to processed (sawn) wood products such as floor boards and counter tops.
In both the United States of America and Canada lumber has a North American connotation and is used to refer to felled trees that are milled into boards. The word timber is also used in America, but more often than not refers only to sawn wooden boards with the smallest dimension of no less than 127mm.
Hardwood Lumber Specs in the Americas
In North America the sizes used for hardwood lumber can vary from those used for softwoods. The hardwood boards used in both the USA and Canada can be of various widths and lengths, but do need to be of a specified uniform thickness.
Hardwoods that are used for furniture manufacturing are felled during the months of autumn and winter. This is because the sap stops running in the trees and allows for a better quality of lumber.
Did you know? Natural sap ruins the natural color of timber and decreases the value of the furniture or flooring made out of it. This is why hardwoods are generally felled in the colder months of the year.
Known Lumber Defects
There are 5 types of lumber defects with specific causes:
Conversion Related Defects
These defects are caused during the felling or milling process and include chip marks from handing and diagonal grain issues due to incorrect cutting.
Fungal Related Defects
These defects are caused by the fungal infections of the wood and include (but are not limited to brown rot, dry rot, sap stain, wet rot and heart rot.
Insect Related Defects
This type of defect is caused by insects such as marine borers, carpenter ants and termites to name but a few.
Seasoning Related Defects
These types of defects are due to seasoning issues with the wood. This is the number one cause for splinters and sliver damage in all types of lumber.