A material that is renewable with a rapid growth rate, for example bamboo that grows two feet per day and 60-80 feet a year and can harden in five years to be equal in strength to a tree 50 years old.
The reason you call it a building is because it was built as you would call something that was carved a carving or something that was painted a painting.
The reason you call it a building is because it was built as you would call something that was carved a carving or something that was painted a painting.