Wood structure timbers are: Douglas fir, Southern pine, yellow cedar, hemlock, spruce, etc. Why do they choose them? First of all, their commonality is high strength, high surface hardness, good corrosion resistance, beautiful texture and strong nail holding power. The light weight of wood is the material of choice for wood-framed houses; these woods are commonly used in China for Pinus sylvestris var. mongolica, red cedar, and Douglas fir; these woods grow faster in the growing season, scientifically planted in Canada, and cut annually. There is no growth cycle in the quantity. It can be said that long-term planting is inexhaustible and belongs to the green renewable natural resources;