Clam wood and iron birch are both very hard woods in China.

1. Clam wood

In order to absorb nutrients, the roots of Clam wood penetrate deeply into the rock crevices, absorb a lot of calcium minerals, and accumulate them in the wood, thus becoming Extra hard.

Clamus alba is distributed in the tropical limestone mountain monsoon forests at an altitude of 700 to 900 meters in parts of Guangxi and Yunnan, China. The distribution center of this species is in southern Guangxi, extending westward to the limestone area of ??southeastern Yunnan, and crossing the Tropic of Cancer to the north gradually becomes an occasional species and disappears. Yuanjiang is already at the northern edge of the distribution of this species and is occasionally seen.

2. Iron birch

The wood of iron birch is three times harder than oak and twice harder than ordinary steel. It is the hardest wood in the world. People regard it as the hardest wood in the world. It is used as a substitute for metal. Iron birch is a rare and endangered wild plant. It is a critically endangered species and is on the verge of extinction. People call him King of Wood.

Iron birch loves light, is cold-resistant, and tolerates drought and barrenness. It generally grows in mountains with an altitude of about 700 meters. However, in the second nationwide survey of wild plant resources launched by the State Forestry Administration in 2012, it was discovered that many iron birches that were more than a century old were found in western Zhejiang.