Hard maple is one of the most well known domestic hardwoods. People know of hard maple for a range of different reasons; finding maple leaves during walks in the forest, playing with their “helicopter” like seeds, maple syrup, and finally hard maple lumber. There are very few people that haven’t been impacted by hard maple products. While the list of topics we could cover related to this species is long, in this blog, we want to focus on how hard maple affects the wood products industry.
Hard Maple in the Forest
Hard maple is a deciduous hardwood with broad leaves that drop in the fall and have seeds that are contained in ovaries. All deciduous trees are hardwoods. For more information on what makes a hardwood, check out this blog!
Hard maple primarily grows in the northeastern part of the USA and the eastern part of Canada. Its trees typically grow to 80-115 feet tall.
Hard maple has a false heartwood, a characteristic unique to maple and birch species. The heartwood is actually a bacterial growth that will form in the center or near wounds of a tree. This is why there are “heartwood” streaks near maple syrup tap holes. This can produce some really unique lumber if enough small wounds are present in a small area.
Manufacturing of Hard Maple Lumber
Hard maple is harvested and processed just like any other whitewood species. White colored woods have a high probability of spoiling and staining while it’s green. To avoid this, it’s best to harvest, saw into lumber, sticker, and dry as soon as possible. When hard maple logs are brought to our plant, the logs are graded and within the next few days, cut into lumber in our sawmill. We saw hard maple in 4/4, 5/4, 6/4, 8/4 thick and in lengths ranging from 4’-16’. We also saw the low grade cants into railroad ties or saw the cants into low grade lumber for flooring or pallet material.
After the logs have been sawn into lumber, that freshly sawn lumber is stickered to allow for airflow to flow between the courses of lumber. The airflow helps remove moisture from the lumber and minimizes the chances of staining. Hard maple should be stickered in a fashionable time after it’s been sawn.
With the lumber stickered, the lumber can be loaded into a kiln. Once again, hard maple should get placed into a kiln as soon as possible to reduce the risk of staining. Lumber in our region is dried to 6-8% moisture content. Drying lumber increases its strength properties, reduces weight, increases machining and gluing properties, and brings the lumber to equilibrium of the environment that it will be used in to reduce the shrinkage of the finished product. Hard maple, along with other whitewoods, is unique in the way it’s dried. The industry standard is to dry hard maple to the whitest, brightest white possible. To do this, hard maple needs to be dried using low temperatures (nothing over 140°F) and with high air velocity (the faster the better.) It typically takes 14 days to dry hard maple from green to 6-8% in a conventional dry kiln.
After the lumber is dried, the stickers are removed. The lumber can be sold as rough, or the lumber is machined to the customer’s desired thickness, width, and/or length.
Hard Maple as a Product
Since hard maple is desired for its color, it is sorted for color to best fit the customer’s needs. Hard maple is sold with a white color sort and an unselected color sort. The white color sort limits the amount of heartwood on the board, providing the consumer with primarily white boards.
At this point, the primary manufacturing process is complete and the lumber is sold to secondary wood manufacturers. Secondary manufacturers take the dried lumber and turn it into a finished product like flooring, cabinets, windows, doors, furniture, moulding, and millwork. Most of these manufacturers have equipment like rip saws, chop saws, moulders, CNC routers, and possibly finishing equipment.
The lumber would first be surfaced to a standard thickness, and then ripped to width, and chopped to length. Usually, knots and other defects are removed when the lumber is ripped and chopped. The ripped and chopped lumber now takes on a new name like rips, blanks, or plugs. The blanks are fed through a moulder and the blank gets profiled into flooring, crown moulding, baseboard, or other similar products. Some windows and doors have curved parts. Typically, these parts are profiled with a CNC router. Any products that need to be assembled are assembled at this point. The last step of the manufacturing process is to stain and finish the product to the customer’s specifications, although some products like hardwood flooring are finished after it is installed.
Hard maple is desired for its color, workability, and durability. It is a closed porous hardwood and has a specific gravity of 0.63. Although it’s dense, it’s not too dense to cause problems while machining and gluing. Its density provides enough resistance to wear and tear to be used as durable flooring or a countertop. It takes stains and finishes very well which makes it a versatile wood. Hard maple has the durability to withstand normal wear and tear for lifetimes.
Hard Maple at Kretz Lumber
We are the pioneers of white hard maple for a reason. In 1990, we designed the first kiln drying process that increased airflow and venting capacities during the drying cycle. This method enabled us to keep hard maple consistently white throughout each kiln charge. Twenty-five years later, customers continue to rave about our unique ability to provide such bright hard maple. Our superior hard maple grows in the most desirable northern hardwood regions of Michigan and Wisconsin and is dried consistently white year round.