What happens to plywood when it is left in direct sunlight?

When plywood is left in direct sunlight, it can experience twisting or cupping due to the effects of heat and moisture. The exposure to intense sunlight can cause one side of the plywood to heat up more than the other, leading to uneven expansion and contraction. This differential movement can cause the plywood to warp, resulting in twisting or cupping.

Maintaining a stable environment with appropriate humidity levels and avoiding direct sunlight are crucial for preventing such warping in plywood. While changes in color can occur with UV exposure, the primary concern with plywood in direct sunlight is the structural integrity and the physical warping that can happen due to uneven expansion. Burls and knots might be characteristics of the wood itself but are not a direct result of sunlight exposure, and the suggestion that plywood becomes flammable isn't accurate in the context of direct sunlight, as plywood does not ignite merely from exposure to light or heat without a significant source of ignition.