In this new Q&A series, I will be answering some questions that the American Hardwood Export Council has commonly been asked at events and trade shows in which they have participated. They all have a common theme relating to the export of American hardwoods to destinations all over the world.

Can you describe the process that takes a tree from the forest to the lumber that arrives at my factory?

There are several steps throughout this process beginning with the hardwood forest itself. The American temperate hardwood forest is a huge and growing resource, which is well-managed and can be utilized for the production of high quality lumber and veneers. The main bulk of the forest resource stretches down the Eastern seaboard of the United States from the Northern states up on the Canadian border down through the Appalachian Mountains to Florida and across to the Midwest states of Kansas and Nebraska.

In most states, a very significant proportion of the forest is privately owned in 10 to 20 hectare lots. Some states such as Pennsylvania and Wisconsin have a higher percentage of state-owned forest, but around three quarters of the entire resource is in the hands of millions of private landowners.

The forest is natural and made up of mixed species, unlike the monoculture seen in softwood plantations. Mature trees are selectively harvested, allowing saplings and smaller trees to grow and mature and the harvesting cycle to keep repeating itself. After the trees have been felled, they are then taken to a sawmill to be processed.

Sawmills are scattered throughout the whole hardwood growing region and vary enormously in size. Some small sawmills just cut green lumber to supply to concentration yards, who will then dry and grade the lumber for resale. Larger sawmills will perform the whole conversion process from logs to kiln-dried lumber.

once the logs are at the sawmill they are sorted into different species and cut to more manageable lengths. At this stage any potential higher grade veneer logs are separated out, while the rest are stacked ready for sawing. The logs are first debarked, then sawn into lumber of various thicknesses depending on what is needed for stock levels and for orders in the system.

The most common thicknesses are 4/4 (25mm), 6/4 (38mm) and 8/4 (50mm). Throughout the conversion process every effort is made to ensure that waste is kept to a minimum to optimize the yield out of each log. All the wood waste (sawdust and chips etc) are utilized as fuel, animal bedding or to make wood-based panels.

Next come the grading and drying processes. The sawn lumber is graded before being sorted into stacks of the same grade and thickness. The lumber is stacked with thin ‘stickers’ in between each layer to help the drying process before either being first air dried or put directly into the dry kiln. This very much depends on the species and thickness.

Kiln drying is a highly complex procedure which can take anywhere from several days for lower density species such as tulipwood to over a year for white oak. The technology and methods have been perfected by the American hardwood industry over more than a century. Attempting to rush or speed up the drying process can potentially ruin the whole kiln load, resulting in big losses.

Hardwood lumber supplied from the United States is usually dried to a moisture content range of between 6 to 9 percent, which is suitable for interior furniture, joinery and flooring purposes. Once dried, the lumber is regraded to remove any lumber that may have been downgraded during the drying process and to get an accurate measurement for determining the price of the lumber.

For export the lumber is then loaded in to a 20 foot or 40 foot container for shipment to the final port of destination before onward transport to the factory. The amount of lumber that a 40 foot container can hold depends on the density of the hardwood species that is being shipped. A typical container will hold approximately 28 cubic meters of oak or 35 cubic meters of tulipwood. Mixed species loads are also possible.

I learnt at a recent AHEC seminar event that there are distinct growing regions in the United States. Could you describe these again please?

There are five main hardwood growing regions in the United States, which contain a wide range of species which have been managed for commercial and non-commercial purposes since the turn of the 20th Century. Each region has a different mix of species and differences in the characteristics of the wood can also be found.

Northern Region:
This area is made up of the Lake States, such as Minnesota, Wisconsin and Michigan, as well as the New England States, such as Vermont, Maine, Massachusetts and New Hampshire. The climate in these areas is characterized by long winters, heavy snow, a cool spring and autumn and a short, hot summer growing season. The predominant species are hard maple and red oak, as well as beech, ash, white oak, birch and soft maple. The trees are generally slow growing, with smaller diameters than in the other regions, but the color of the wood is often very uniform.

Midwest Region:
This area is made up by the states that run South from Wisconsin to Missouri and West, from Ohio to Iowa. The climate of this area is more moderate, with cold winters, mild springs and autumns and hot summers. The predominant species are red and white oak, hard and soft maple and walnut, as well as ash, cherry, hickory and others. The trees, which have larger diameters, tend to be scattered throughout the region, since farming corn and soybean is the main industry here. This is probably the best growing region for American black walnut.

Southern Region:
This is a vast area of the country, which ranges from Texas to Florida. It enjoys mild winters, a short spring and autumn and long, hot summers and a longer growing season. The predominant species are red and white oak, pecan and ash, as well as cottonwood, gum, sycamore and tulipwood. The trees are faster growing than in the Norther region, taller and have larger diameters.

Appalachian:
This is another vast region, which extends from Georgia in the South, right up to New York in the North. The Appalachian Mountains dictate the climate, growth rate and species makeup here, due to a variety of elevations within the overall growing region. Just about every major species grows in this region, but it is home to the largest concentration of cherry. This region is truly the breadbasket of American hardwoods.

Pacific Northwest Region:
Characterized by a maritime climate and separated from the main geographical growing regions in the East. Red alder and Pacific Coast or big leaf maple grow exclusively here. This explanation offers only a brief description of the growing regions and species available in these areas. I cannot include every species available, nor must you draw any definitive lines demarcating any specific region.

Which is the best region of America to buy from, depends on a variety of factors, including the type of product that is being produced. Take maple for instance; for high end joinery and cabinets, where color is critical, you will probably be better off sourcing lumber from the Northern region where hard maple is more consistently white in color. However, if you are producing smaller items in maple where color is perhaps less important, then other regions could be considered at a more advantageous price.

*This article has been supplied by the American Hardwood Export Council (AHEC). For more information on American hardwoods and to learn more about different species and
grades, please visit www.americanhardwood.org.