After a long period of efforts, experts from the classical school represented by the Palace Museum and the academic school represented by the China Academy of Forestry finally reached a * * * knowledge, and scientifically defined the tree species belonging to the category of redwood and their technical parameters such as structure and density. Three conditions that mahogany must meet at the same time are clearly defined.

(1) Tree species: five genera, seven categories, five genera: red sandalwood, Dalbergia odorifera, persimmon, cliff bean, ironwood; Seven categories: rosewood, rosewood, rosewood, rosewood, ebony, striped ebony and wingwood.

(2) Structure: The wooden structure is very thin, and the average chord diameter of the conduit is below the specified value. The specific standards are: mahogany: the average chord diameter of the catheter is not more than160μ m; Rosewood, black rosewood, red rosewood and chicken wing wood: the average tangential diameter of the catheter is not more than 200 microns; Ebony and striped ebony: the average tangential diameter of the catheter is not more than150μ m.

(3) Density: When the moisture content of wood is 12%, the air-dried density of all types is above a certain value, specifically: rosewood: the air-dried density is greater than1.00g/cm3; Redwood: air-dried density is equal to or greater than 0.76 g/cm3; Black rosewood, red rosewood, ebony and striped ebony: air-dried density is equal to or greater than 0.85g/cm3；; Chicken wing wood: air-dried density is equal to or greater than 0.85g//cm3.

Because the characterization of mahogany raw materials is a science, it is impossible without standards, and the standard restrictions are too dead, which is not conducive to its development. Therefore, some supplementary explanations are needed:

(1) Ebony: This term is the most popular in Japan and is considered as the best ebony wood product by contemporary Japanese. It is understood that in fact, it is mainly striped ebony, and a small amount is ebony or blackcurrant.

(2) Gall wood: It was called Gall wood in ancient China, because it was a tree tumor caused by disease. It is not surprising that there are local tumors on wood, but a few rare trees will grow bigger tumors, and some will even grow into hollow trees, and all nutrition will be concentrated on tumors. The fibrous tissue inside this tumor has changed, forming various beautiful patterns, which we call "beech". There are many kinds of beeches. Such as birch gall, maple gall, cypress gall, pear gall, etc. Among them, pear gall is the most precious. Some panels of classical mahogany furniture handed down from generation to generation are made of this kind of beech. Galla chinensis has gorgeous wood, is not suitable for deformation, is very rare, and is a very valuable decorative material.

(3) White sour branch: The new national standard has classified it as red sour branch, and it will not be subdivided.