How to Identify and Choose Wood Species – Wood Grain and Texture

Introduction

The appearance is a crucial aspect that significantly influences people’s decision when buying engineered flooring. Along with color and size, there are also more nuanced and tactile characteristics of the top layer wood lamella to consider. This article presents the grain and texture variations of various wood species utilized in the decorative top layer of engineered flooring, highlighting their differences in appearance and usage.

Grain Direction 

Grain direction refers to the alignment of the primary cells in the wood, which can vary among tree species. It is typically not discernible through endgrain examination but can impact the wood’s workability and appearance. Grain direction is commonly categorized into the following:

• Straight: As the name suggests, this denotes species which grow straight and parallel with the tree’s trunk. Straight-grained woods are generally easiest to work and machine with minimal complications. Their mechanic strength is high and stable for their uniform grain.

• Spiral: Some tree species grow with the grain at a slight incline, with a spiral-like pattern circling the trunk, like eucalyptus and oriental arbor vitae .

• Interlocked: Taking spiral grain a step further, interlocked grain occurs when spiral-grained trees change directions, and spiral back and forth throughout the trunk, alternating between right-hand and left-hand spirals. Depending on the slant of the spiral, and the frequency of the direction changes, woods can be either shallowly or strongly interlocked.

The grain spiral direction change can be seen the clearest on quartersawn surfaces, which creates a ribbon stripe figure. The interlocked grain direction makes the veneers resistant to splitting. 

• Wavy: Just as the name implies, this grain pattern indicates when the grain of the wood grows in a wavy fashion. This pattern is most clearly seen in flatsawn sections of wood, like horse chestnut (Aesculus hippocastanum) and cherry.

The sketches of the upper three grain directions are illustrated below.

• Irregular: This is a more ambiguous catch-all term that describes wood grain that swirls or twists in an abnormal way. Irregular grain can be due to a number of factors, such as knots, burls and large branches.

Texture

Wood texture refers to how a particular wood feels when touched. Even after sanding and smoothing, different types of woods have varying levels of smoothness. Some woods feel soft and rough to the touch, which is known as a coarse texture, while others have a smooth and glassy feel, referred to as fine texture.

The uniformity of the texture also depends on the size and distribution of pores, especially within the earlywood zone. Wood can have an uneven texture, but diffuse porous woods with small pores are generally the most evenly textured.

If a wood species has large, open pores, like Red Oak or Wenge, the finished surface will likely be grooved with tiny slits and valleys where the finish settled into the pores, and a pore filler will be needed to get a glassy smooth surface. However, if the pores are small or very small, like in the case of Hard Maple, the wood can be finished to a smooth and level surface without the need for pore fillers.

Grain and texture of wood species in engineered flooring

Summary

In addition to wood grain and structure, there are many other factors that can influence the appearance of flooring, such as color and luster. However, grain and texture can also affect the processing performance of engineered flooring. Therefore, understanding wood grain and texture can help us analyze the possible defects in the flooring from the perspective of formation mechanism, such as warping and cracking, and thus improve the process and increase the product pass rate.