mid-timber diameter

例句：

1. 1. The tree's trunk is about 2 meters in diameter.
   这棵树的树干大约2米宽。
2. 2.The beam was cut to the mid-timber diameter.
   梁被切割到中材直径。
3. 3. The construction project required a mid-timber diameter beam.
   这个建筑项目需要一根中材直径的梁。