This product represents a typical load of 2x4 and 2x8s. Random lengths of lumber were commonly shipped in this way up through the 1960s with some shipments into the 1970s.
If you are modeling the 50s or earlier then you would want to rough frame the load with wood dividers down the middle.
If you are modeling latter periods then you would want to band the stacks. Wood divders would still be used. If fork lifts were likely then bottom pieces would be used to make room for the fork lift forks under the loads.
The largest stack in this set is a scale16' long. Stacks are scale 56" +/- 3" high.