Natural veneer has an impact on different growth cycles

Natural veneer is taken from logs, and the wood formed during each growing season is called a growth ring, which forms a concentric circle around the pith center on the transverse plane. In cold or temperate regions, trees only have one growth season a year, that is, only one additional round of wood is added to the transverse plane, so the growth ring is also known as the annual ring

In tropical regions, the climate does not change much within a year, and the growth of trees is almost uninterrupted throughout the year. They can grow several times a year, and they are closely related to the rainy and dry seasons, so they cannot be called annual rings.

The growth ring presents different shapes on different sections, forming a concentric circle around the pith center on the transverse section, a clear parallel strip on the radial section, and a parabolic or "V" shape on the transverse section of the chord. The growth rings exhibit different widths at different tree age stages. Generally speaking,

Trees in their early stages grow rapidly and have a wider growth ring; During the strong age period, the growth rate slows down, the growth amount decreases, and the growth ring narrows; During the aging period, the growth rate decreases and the growth ring becomes narrower. Natural veneer will present different styles when cut into tree shapes.

Within each growth ring, the wood near the pith center, which is formed in the early growth season, has a faster cell division rate, larger volume, thinner cell walls, softer material, and lighter wood color. This part is called early wood; And the part near the bark, that is, in the late growing season, is nutritious.

The material flow ability weakens, and the activity ability of the primitive cells in the cambium gradually decreases, leading to weakened cell division. As a result, cells with small cavities and thick walls are formed, resulting in dense materials and darker colors. This part is called latewood. Due to the different structures from early wood to late wood, in two growth rings

There are significant differences in the organizational structure of the areas where the materials intersect, clearly highlighting a boundary called the wheel boundary.

The transition from early wood to late wood varies from slow to fast, and there are great differences among different tree species, such as Larix gmelinii and pinus tabulaeformis of coniferous wood and ring hole wood of Broad-leaved tree; However, coniferous wood, such as Korean pine, spruce and Broad-leaved tree, is loose, porous and semi loose

The transition boundary from early wood to late wood with ring pores is not obvious, which is a slowly changing wood. The width of the growth ring varies with different tree species, age, and growth conditions, and there is a certain relationship between the width of the growth ring and the mechanical strength of the wood.

It is generally believed that coniferous wood has a wider growth ring and relatively lower mechanical strength; If the growth ring is narrow, the mechanical strength of the wood is relatively high. The mechanical strength of wood is usually measured by its latewood percentage (latewood percentage refers to the percentage of latewood width to the width of the growth ring). this