Wood is a ubiquitous material in our interiors, whether in construction or furnishings. It is used for all kinds of furniture, from tables to chairs, from beds to walk-in closets... It is praised for its many qualities, but also for the fact that it can be worked in various ways.
The diversity of trees found on Earth makes it possible to offer wood with a variety of appearances. When crafted by hand and left as untreated as possible, it becomes a high-quality piece with a rustic aesthetic.
Wood is a premium raw material that everyone is at least superficially familiar with, yet its production holds many surprises. In this article, we’ll introduce you to the different types of wood, their quality, and how they’re processed.
I – A wide variety of woods with unique characteristics
There are many forested areas in mainland France. And for good reason: they cover nearly 17 million hectares, which is slightly more than 30% of the country’s total land area. Since 1980, France’s forest area has grown by 0.7%.
In terms of area, France's forests rank fourth in Europe. There are 138 different tree species there. A treasure trove of diversity that, as you will see, is not always put to good use.
Trees in France can be divided into two broad categories: deciduous trees (or angiosperms) and conifers (or gymnosperms). Deciduous trees, as the name suggests, are trees with well-developed leaves that are deciduous, meaning they are shed in the winter. Conifers, also known as coniferous trees, have needles instead of leaves, which they retain throughout the year.
A. Deciduous Trees
Deciduous trees are the majority in the country, as they account for two-thirds of France's forests. This abundant resource is used in the construction of roof trusses and furniture, as these are wood species recognized for their quality in the construction industry.
Among the most commonly used woods in this category is oak, which is the most widespread and highly regarded tree in France and even internationally (see the article in "Holzmarkt"). It is a light-colored, hard, and heavy wood that is extremely durable. It is used for interior and exterior construction as well as for joinery.
Did you know?
To rebuild the roof truss of Notre-Dame Cathedral in Paris following the 2019 fire, 1,000 oak trees from all over France were carefully selected. The original roof truss dated back to the 13th century—a testament to the strength and durability of this wood.
Beech is the second most common type of wood in France. It has a uniform grain and is mainly used in cabinetmaking for furniture. Unlike oak, it is a wood intended for indoor use and is highly prized for its fine grain.
Another commonly used hardwood is poplar. It is a light-colored, soft, lightweight, yet very durable wood. To enhance its value, it is primarily used in the manufacture of plywood (see next point).
Hardwoods also include chestnut, ash, cherry, and walnut, to name just a few.
B. Conifers
Coniferous trees make up one-third of France's forests. Coniferous trees are often used in construction, for plywood, and for fiberboard, since they are less expensive and easier to work with. They also grow quickly but are less dense than deciduous trees, which is their main difference.
As mentioned earlier, softwoods are coniferous trees, of which the spruce—which grows in mountainous regions—is the best known. It is also frequently used as a Christmas tree. It is a soft, uniform, and very light-colored wood. It is quite affordable.
There is also the Scots pine, a commonly used type of wood that is abundant and easy to work with. It is hard and dense, and its color ranges from cherry yellow to reddish brown.
Finally, among the remaining conifers is the fir, which has similar qualities to the two mentioned above, namely: an inexpensive, abundant softwood that is widely used in construction, such as for roof trusses. Other well-known conifers include the Douglas fir, the larch, and the maritime pine.
There is a wide variety of tree species, some of which can be confused with one another because they look so similar. Nevertheless, certain tree species are preferred over others in specific areas. To provide a clearer and more general overview, there is a classification system divided into four categories. Within each category, there are different types of wood, ranging from light to hard, depending on density:
Class 1 or A: This refers to light woods such as poplar, pine, and fir.
Grade 2 or B: applies to fine woods used for furniture, such as walnut, birch, or teak.
Class 3 or C: These are very hard woods such as oak, beech, ash, or acacia.
Class 4 or D: This category includes the most durable woods, such as dark acacia, cedar, and wenge.
The Quality of the Wood
People talk about density when classifying types of wood, but did you know that growth rate is important? The slower a tree grows, the stronger it is. This is essentially true for deciduous trees. In contrast, conifers are generally considered less durable because they grow faster.
However, there are other factors to consider when assessing wood quality, such as growing conditions and the time of year when the tree is felled. Even the lunar cycle plays a role, as it affects water circulation within the wood.(1)
It is also possible to sort them by color, but there is no "official" classification for that.
Once the wood has been harvested, it is processed for a wide variety of purposes depending on its properties and the specific requirements of each application. Even though wood is considered a healthy material, it may contain toxic elements by the time it has been fully processed. This depends on how it is used.
II – Wood Processing: Inconsistent Quality
Wood can be processed in many different ways, resulting in varying qualities and outcomes. Depending on the type of wood panel used, the price and durability will vary. We focus on panels intended for furniture manufacturing.
A. Sperrholz
Plywood consists of layers of wood that are glued together. The thickness of the sheet varies depending on the number of layers and the thickness of the individual layers. The most commonly used wood species in this process is poplar. The way plywood is manufactured ensures its uniformity, water and fire resistance, as well as its lightness and versatility.
Unlike untreated wood, plywood is not affected by moisture or temperature fluctuations. It is relatively environmentally friendly, as the types of wood used to make it come mainly from sustainably managed forests (poplar, pine, beech, etc.). In addition, the production of plywood requires very little energy.
However, it is important to remember that glue is used to bond the layers of wood together. This is not insignificant in terms of VOC emissions. It should be noted that, fortunately, there are also natural, water-based adhesives available.
Just for the record...
The method of manufacturing plywood panels was already in use in ancient Egypt and ancient Rome, where it was used to make shields. During World War II, plywood was used in the aviation industry as a lightweight and sturdy material.(2)
B. Glued-Laminated Timber
Glued-laminated timber (BSH) consists of solid wood lamellas that are glued together along the grain—that is, across the width or length—and have a thickness of 33 to 45 mm. It allows for very long pieces of several meters when needed. Glued laminated timber is a good alternative to solid wood, which we will discuss later (in carpentry, it is actually referred to as “solid wood”). It is very popular in the furniture industry due to its high resistance to warping, which even exceeds that of solid wood. The woods most commonly used to produce this material include spruce, oak, beech, and Scots pine.
From an aesthetic standpoint, the interlocking strips are visible. Therefore, this unique appearance should be appreciated. On the other hand, care should be taken to ensure that laminated wood is processed by professionals who use appropriate, non-toxic products. Poorly glued strips can lead to problems with fungal or insect infestation.
1) Agglomerate
This material is a mixture of wood chips, sawdust, and other recycled plant waste that is compressed at very high temperatures and then bonded together. Synthetic or natural resin is used for this purpose. Its thickness ranges from 3 to 50 mm. Nearly 80% of all cabinetry is made from particleboard. It can be found absolutely everywhere.
It is a very inexpensive material that is soft and therefore easy to drill. However, it should be handled with care to prevent cracking. It is not very durable and does not hold up well under heavy loads. You should also find out about the binder used, as it may contain substances harmful to health, such as formaldehyde.
It is not very aesthetically pleasing and is generally reserved for the least visible parts of the furniture.
2) MDF (Medium Density Fiberboard) or Medium
MDF is a particleboard made from wood fibers derived from hardwoods or softwoods.
It is very smooth and uniform, as it lacks the unevenness typical of raw wood. It is a very durable material, as it rarely splits when cut and is largely unaffected by moisture and temperature fluctuations. It is valued for its low price and is easy to work with—that is, it can be painted, varnished, sawed, and sanded. However, just like particleboard, MDF must be drilled carefully to prevent splintering.
One of its drawbacks is that it scratches relatively easily. However, MDF is primarily used for shelves in cabinets and dressers. Finally, MDF also contains formaldehyde, which poses a problem for indoor air quality, especially for DIYers who are exposed to toxic dust. Therefore, it is advisable to wear a mask when cutting this material.
3) Melamine
Melamine is a surface treatment applied to particleboard or MDF panels. It consists of a decorative film impregnated with a thermosetting resin (melamine-formaldehyde). The panel is melamine-coated and is used for furniture. Thanks to its coating, it is easier to clean than other types of panels. It offers numerous options for customizing furniture.
But here, too, the fact remains that, due to their formaldehyde content, they are a source of indoor air pollution. They may be practical and economical, but unfortunately, furnishing your home with melamine-coated panels is not healthy.
C. Solid Wood
Solid wood furniture is the result of processing raw wood in a way that preserves its natural properties. It is the least processed type of wood panel. It is authentic and timeless. Its ability to withstand the test of time makes it a refined piece of great value. This is also reflected in its price, which is quite high.
Its uniqueness and durability make it a luxurious item that can be resold secondhand or passed down from generation to generation.
It is a living material that continues to evolve over the course of the seasons and may therefore change in appearance after a few years. Whether this happens depends on the type of wood used, the ambient humidity, the amount of light it is exposed to, and temperature fluctuations.
Just as there is a classification of wood species based on their density, there is also a classification that relates to the wood's resistance to moisture:
Class 1: Dry wood used indoors. Moisture content below 20%.
Class 2: Dry wood that is occasionally exposed to a moisture content of more than 20%.
Class 3: Wood that is frequently exposed to relative humidity levels above 20%.
Class 4: Wood that can withstand constant exposure to relative humidity above 20%.
Class 5: Highly durable wood that can come into contact with seawater.
III – The Preferred Selection Criteria for a Piece of Furniture
You already have a lot of information about wood species and how they can be processed (even though we do not claim to be exhaustive). Our goal is to raise awareness that every purchase has an impact—whether on health, the environment, ethics, or all three at once. We recommend that you choose sustainable and healthy products. To do so, there are several criteria to consider:
A. Strength
Every type of wood has interesting properties, but it isn't always appreciated for what it is. A simple rule: The less the material has been processed, treated, or painted, the more valuable it is. It is often the lower-quality materials that require further processing and the addition of products that are often harmful.
For this reason—and if you can afford it—solid wood is the better choice. Its durability is well established, since we all have an example of an old family heirloom that remains in excellent condition.
If you can't afford a new one, it's possible to buy one secondhand, provided you're confident in your purchase. Of the other types of wood panels available, however, laminated wood is recommended because it is high-quality and more affordable. Plywood is also a good alternative to laminated wood, provided these panels are manufactured by professionals who use products that are as natural as possible.
B. Products for Finishing
Nearly all products are enhanced, processed, or protected using finished products based on paints, varnishes, adhesives, or waxes. This is normal, as these products are essential for ensuring the durability of the items.
Unfortunately, it is very often these ingredients that cause VOCs and, consequently, environmental pollution. Just as with a list of ingredients, we recommend that you learn about the types of products used. Some are more toxic than others, and some are harmless (e.g., natural, water-based products). Ask manufacturers how their furniture is made. The more transparency there is regarding the manufacturing process and the materials used, the more reassuring it is.
C. Origin
Another rule to keep in mind is the product’s origin. This means finding out the country where it was manufactured and giving preference to products with shorter supply chains. As you’ve seen, France has no shortage of forests, so its wood is highly sought after in China and the U.S., which purchase it in large quantities (see article: The Furniture Market). Knowledge of and craftsmanship with wood is a recognized skill. Choose companies that work with local artisans, or buy directly from the artisans themselves if you have the opportunity.
Then you can be sure that you'll receive furniture that has been crafted with passion and is of remarkable quality.
D. Aesthetics
The last—and by no means least—criterion is aesthetics. It goes without saying that you should like the piece of furniture you choose and that it should blend harmoniously with your interior decor. If you like wood, then you’ll also appreciate its rustic and warm appearance. Pieces with a simple design are a safe bet—they won’t get boring too quickly—and can be spiced up with decorative elements without compromising their quality.
Light-colored floors are very popular because they fit the Nordic trend. They’re generally easier to coordinate with other elements, since the floors are often light-colored as well. But this isn’t a hard-and-fast rule, because mixing different shades can also lead to a very beautiful result.
We hope this overview has helped you learn more about woodworking and the incredible diversity of wood. At KIPLI, wood is a very popular material because it meets all the criteria we look for: it’s healthy, sustainable, renewable, and timeless. That’s why some of our furniture is crafted exclusively from this natural material. In this age of throwaway culture, we champion the enduring nature of our products by crafting them using traditional, local methods.