Wooden boxes are often used for heavy duty packaging when
- high strength is needed for heavy and difficult loads
- long term warehousing may be needed.
- large size is required
- rigidity and stacking strength is critical
Boxes and crates are not the same. If the sheathing of the container (plywood, lumber, etc.) can be removed, and a framed structure will remain standing, the container would likely be termed a crate. If removal of the sheathing resulted in there being no way of fastening the lumber around the edges of the container, the container would likely be termed a wooden box.
The strength of a wooden box is rated based on the weight it can carry before the cap (top, ends, and sides) is installed. "Skids" or thick bottom runners, are sometimes specified to allow forklift trucks access for lifting.
Performance is strongly influenced by the specific design, type of wood, type of fasteners (nails, etc.), workmanship, etc.