Wood products are an integral part of our everyday life. Wood products are used in large scale items like home, apartment and tall building construction, infrastructure, furniture, decks, piers, and flooring, but also small-scale things like decks, treehouses, toys, instruments and even kitchenware. AF&PA members have adopted a sustainable approach to harvesting wood and a 2012 report from the U.S. Forest Service indicates that over 3.2 million trees are planted per day in the United States. As a result, there are more trees in the U.S. today than there were 50 years ago.
What are Wood Products?
The paper and wood products industry makes essential and innovative products for everyday life. When trees are harvested, they go on to make all types of paper and wood products. The logs from the harvest are debarked and cut into boards and planks. Parts of the tree may go on to be pulped and turned into paper products. Additionally, leftovers from the manufacturing process are used to generate power for mills ensuring there is nothing left behind.
In general, high-quality wood at the base of the tree is generally used for higher value products like veneers and big pieces of lumber. Wood towards the middle of the tree tends to go towards things like wood pallets and smaller pieces of lumber. The thinner wood towards the top of tree and other logs not suitable for saw timber are turned into chips that are made into wood pulp for paper products like packaging, tissue, copy paper and more.
Small branches and tops can sometimes be used for biomass fuel, but the industry also wants to leave some material in the woods to improve soil quality, retain moisture and provide habitat for wildlife.
What Kinds of Products are Made from Wood?
Wood is used in a broad range of products and applications, some we don’t remember or think about. Commonly, wood from harvested trees goes on to become:
- Lumber: Lumber is harvested trees that has been turned into planks or boards. It can be either softwood or hardwood and the application of the lumber depends on the type of wood. Lumber commonly used in structural materials, but can also be used in cabinetry, furniture, flooring. Lumber is generally categorized by thickness and length.
- Engineered Wood Products: Engineered wood products are a combination of wood or wood byproducts and various adhesives to make different products. This is an overarching category of many types of products used in all different types of applications. Engineered wood products and applications include plywood, particleboard, laminate flooring, structural composite lumber, medium-density fiberboard, cross-laminated timber, pre-fabricated wood I-joists and glued-laminated timber (glulam), among many more.
- Structural Composite Lumber: Structural composite lumber (SCL) products are engineered through layering wood veneers, strands or flakes and adhesives, which are then cut into specific sizes. Common types of structural composite lumber types are laminated veneer lumber, parallel strand lumber, laminated strand lumber and oriented strand lumber. They are used to make things like rafters, beams, joists and studs.
- Panels: There are both structural and non-structural panels. For example, plywood and oriented strand board can be used in construction applications whereas particle board and medium-density fibreboard (MDF) are primarily used in furniture or cabinetry.
- Mass Timber: Mass timber is a new and innovative style of wood construction where large wood beams and thick panels are used for walls, and roofs and allow for construction of buildings far taller than traditional light frame methods most commonly associated with wood construction. Types of mass timber include cross-laminated timber (CLT), glued-laminated timber (glulam), nail-laminated timber (NLT) and dowel-laminated timber (DLT). SCL of a certain size can also meet code requirements for mass timber.
But did you know that since the industry uses nearly all parts of the tree in the manufacturing process, wood byproducts and wood building blocks like cellulose go into more than just building materials and paper products? During the manufacturing process, sawdust and woodchips are created, which can go on to become fuel to power mills or go into engineered wood products. Additionally, the pulp wood goes on to make fiber based products as fluff pulp, paper sheets, tissue, paperboard and containerboard. Further, chemical-processed wood results in cellulose that goes into things like your LCD screen or rayon textiles. Efficient use of the tree minimizes waste in the manufacturing process and provides valuable products you use in everyday life.
Why Use Wood Products?
Wood Products are Sustainable
Wood products are made from a renewable resource – trees – that are replanted to ensure a sustainable supply. Moreover, they are less energy- and carbon-intensive to produce than competing materials like concrete and steel. And, wood products store carbon. Meaning, as a tree grows, it sequesters carbon and when the tree is turned into building materials that carbon stays locked away in the finished materials for decades. Additionally, studies have shown that building with wood produces fewer greenhouse gas emissions than building with other materials.
Wood Products Keep Forests as Forests
The demand for wood products helps keep forests as forests. Through sustainable forest management, tree farmers harvest and replant trees responsibly, taking into consideration wildlife, diversity of plant species and forests ability to create watersheds and sequester carbon.
Using less wood and paper products decreases the incentive to replant after harvest and keep land in forests and increases the likelihood they will be turned into other land uses like parking lots, subdivisions or pastures.
Wood Products are Innovative
There is an increasing demand for more sustainable, renewable solutions for the built environment and the industry is meeting that demand with wood. Innovative building designers, engineers and researchers are seeing successful implementation of tall wood buildings across Canada, Europe and other parts of the world are aiding in the drive to implement them in the United States.
Wood’s strength-to-weight ratio is comparatively higher than steel while containing a fraction of the embodied energy. Wood delivers durability and seismic resiliency necessary for tall buildings while offering code-compliant fire resistance. Mass timber products offer inherent fire-resistance characteristics that are critical in structural applications.
How are Wood Products Made?
First, trees from sustainably managed forests or plantations are harvested – meaning a specific area of the forest landscape is cut. The branches and leaves of the harvested trees are removed and left to provide cover and provide nutrients for the new trees. Then the trees are cut to convenient lengths for loading and transported to the lumber mill.
Logs are loaded onto a conveyor that brings them into the mill where they are debarked either with grinding wheels or high-pressure water while the log is rotated. The bark that is removed can go on to be used as something like garden mulch or it is burned as fuel to power the mill.
Next, logs go through a saw that’s usually guided by a computer with a laser that cuts the log into various rough-cut boards to maximize yield. Then the rough-cut boards are sorted again by length and species. Boards of a specific length and species are loaded into a kiln for the drying process to ensure product quality for the customer. The cut and seasoned boards next go through a planer that smooths the wood into finished lumber where it is then graded. Finally, the lumber is stacked, banded and wrapped so it can be loaded for shipment.
To make a product like plywood, debarked logs are loaded onto a conveyor where a saw cuts them into lengths that are known as peeler blocks. The peeler blocks are soaked in hot water to soften the wood. Next the softened peeler blocks go into the peeler lathe and as the lathe rotates, a knife peels a continuous thin sheet of veneer from the block.
Next, the sections of veneer are sorted and stacked according to grade and then fed into a dryer. Once the sections of veneer are dried, they are stacked into layers so they can be glued. The glued sheets are loaded into a hot press at 90 degrees from each other to strengthen the end product and are squeezed together under pressure while being heated to cure the adhesive. Finally, the plywood sheets are trimmed to their final length and sanded.