We use ply wood (ie structural panels) all the time, but we may take them for granted. Ply wood has come a long way in about a hundred years, and here is why.
In 1905, we started to use plywood which is essentially thin strips of veneer that go through a process of cross-lamination before then being glued. Rather than small strands, this used whole layers of logs so it appears less rough and can be more consistent when compared to oriented strand board (OSB).
Towards the 1970s, we saw the introduction of particle board and this has similar properties to OSB except the misalignment of wooden strands. A decade later, OSB was developed and uses heat-cured adhesives.
To achieve the cross-oriented layers, these are then arranged with rectangular wood strands. Generally boasting a consistent quality, OSB can be produced in large continuous batches. Despite its youth, OSB took over plywood as a building material in the US at the turn of the millennium.
Mike McFadden, Certified Master Home Inspector in Orlando, FL