This is a wood encyclopedia where you can find different kind of woods. You can check what kind of wood information do you want to read.

Types of wood

Angiosperm species of temperate zones. They have a more complex woody structure, are often harder and have medium penetrability.

Angiosperm species of tropical areas. They differ in that they are usually rich in extracts, not very unpredictable and of darker tones.

Gymnosperm species characterized by being normally clear, soft, impregnable and rich in resins.


Conifers


Leafy


Tropicals

Description of parameters for classification of wood types

This encyclopedia consists of a list of wooden letters with information that we consider useful as a starting point for understanding different species. They refer to the description of wood, its physical and mechanical characteristics, durability, work performance and its main uses.

Names and definitions: there are thousands of tree species and it is common for them to have different common names depending on the area and country. For this reason, and to avoid confusion, each card includes the scientific or botanical name of each type of wood.

Description of wood species

The descriptive characteristics of each type of wood can generally be applied to each species, however, we must be aware that each tree is a unique living being and, therefore, there may be differences, mainly in terms of colors.

Color: The description of the color of the wood considers the possible variations that may exist without taking into account extreme cases such as wood exposed to bad weather.

  • Sapwood and heartwood: together with the bark, they are the parts that make up the trunk of a tree. The sapwood is just behind the bark and is “biologically alive”. It is where you drive or circulate from the foliage to the roots. This part of the wood is usually softer, lighter and lighter in color. The heart is the inner part. It is the wood that no longer has a conductive function, is harder and dense, more resistant to attack by insects and generally darker in color. When describing a wood, it is common to point out whether there are significant differences between the heartwood and the sapwood, or if, on the contrary, it is difficult to distinguish between them.

Virtually all wood species change their color when exposed. In some it is an imperceptible change, while in others it can be seen with the naked eye.

Fiber: It is the set of cells arranged in the direction of the tree’s axis, discarding vascular elements and parenchyma cells. The different variations it can have in dimensions and layout give rise to the following types of fiber: straight, wavy, twisted, interlaced.

Grain: In conifers the grain refers to the diameter of the tracheids, while in hardwood it refers to the diameter of the vessels. The grain is classified into the following categories: thick or thick, medium and fine.

Note: These last two concepts, grain and fiber, have important implications for the workability of the wood and the final result of the work: difficulty in brushing and cutting, resulting in the quality of the finish …

Physical properties

The values ​​of physical and mechanical properties (average values) are calculated from tests carried out in laboratories or obtained in the international literature. They should be used with caution due to the highly variable nature of wood properties. This variability is well known to people working in the timber industry. It depends on several external or internal factors: age of the trees, position of the wood within the trunk, maturity of the wood and growing conditions (including soil type, precipitation and climate).

Density. The density or relative density of a solid is the ratio of its mass per unit volume, in our case expressed in kilograms per cubic meter. To standardize, it was established in laboratories of international level the use of wood with moisture content of 12%.

woodConifers (kg / m3)With leaves (kg / m3)
Too much light<400<500
Light400 – 490500-640
Semi-heavy500 -590650-790
Heavy600-700800-950
Very heavy> 700> 950

Toughness: This is an important feature because it will allow us to know the resistance to the impact of wood and thus establish whether it is possible to use it in certain situations: parquet flooring, roofs….

By hardness, we understand the resistance that one material opposes the penetration of another.

There are different methods or tests to establish a classification of the hardness of the wood. The most popular are Monnin (Chalais-Meudon), Brinell and the Janka scale. They are all based on exerting force on an object with certain measures to introduce it at a specific point. The strength required for this will give us the value of hardness.

In this encyclopedia, we mainly use the first of the methods mentioned, Monnin, the most common in Europe. On some occasions, when the values ​​of the Monnin test were not found, the values ​​obtained by one of the other methods can be quoted.

Hardness (1 / mm)Class
0.2 – 1.5Very soft
1.5 – 3Soft
3 – 6Half hard
6 – 9Difficult
9-20Very hard

Stability – volumetric contraction coefficient: The volumetric contraction of a piece of wood is defined as the volume variation that it suffers when its moisture content varies by 1%, that is, how much the volume of the wood changes when its moisture degree changes.

The lower the volumetric contraction coefficient, the more stable (less nervous) the wood will be against changes in the degree of humidity.

This concept is related to the hygroscopic property of wood. Accordingly, wood tends to absorb or lose water depending on environmental conditions.

Coeff. Volumetric contraction of the unitInterpretation
0.15 – 0.40A little nervous
0.35 – 0.49A little nervous
0.40 – 0.55Moderately nervous
0.55 – 0.75Nervous
0.75 – 1Very nervous

Mechanical properties

Due to anisotropy of its structure (general property of matter according to which qualities such as elasticity or resistance vary according to the direction in which they are examined), when defining their mechanical properties, the directions perpendicular and parallel to the fiber are considered. In this fact lies the main difference in behavior in relation to other materials used structurally, such as steel and concrete.

In other words, some properties of a wood, such as strength or elasticity, are different depending on the direction in which they are measured. Therefore, different values ​​are usually offered:

  • Compressive strength parallel to fiber.
  • Compressive strength perpendicular to the fiber.
  • Resistance to static bending.
  • Tension parallel to the fibers.
  • Elasticity modules. It measures the wood’s ability to resist warping (the higher the value, the stiffer the wood is). This is an especially useful indicator in the world of wood construction.

Durability

The natural durability of wood is considered, not once treated. The sapwood’s durability is also not taken into account, by default it is considered non-durable.

The durability of wood is determined by its resistance to biological agents (fungi and insects) and to atmospheric agents (sun, rain, humidity or changes in temperature).

It should not be interpreted absolutely. The fact that a species of wood is classified as durable does not mean that it is immune to the attack of termites or other insects.

Workability or technological properties of wood types

Here, information is collected on the behavior of wood types in view of the technological aspects of their transformation processes. The most common processes to which a wood is subjected are:

  • Sawn.
  • Drying.
  • Brushed.
  • Glued.
  • Nailed and screwed.
  • Finishing application.

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