主题：【讨论】奇文推荐：贫穷落后的美国，一个留学生的感叹 -- 探赜索隐

Because US imports oversea timbers, especially from Canada, very cheaply. Not only the poles, they use timber to build all houses. Timber is in shortage in China so we stopped building with timber tens of years ago. When I was in the university, we used to have a course "Wood Structure Engineering" but it was cancelled in late 1980's because there were no longer wood structure any more in China.