Why don't Chinese railways use wooden sleepers?

Sleeper railways were widely used before 1970s, because the railway mileage was short at that time. However, the biggest problem of sleeper pad oil is that it is easy to be corroded and damaged by long-term wind and rain, and the nails are easy to fall off, which has a great impact on safety, and the train speed can not be too fast, which has many shortcomings. Furthermore, China's forests and forest areas have decreased sharply, and the use of a large number of sleepers will seriously damage China's forest resources, resulting in a large number of water map losses, which is not conducive to ecological protection. Therefore, in the late 1970s, the sleeper was faded out of the historical stage.