Back Panel of Campaign Chest

[dzj]

I ran into this mid 19th century chest of drawers on the internet.
http://www.campaignfurniture.com/archiv ... &archive=0
I am curious about the back panel.
As far as I can tell from the photograph, it is set snugly in a rebate. I would think there'd be expansion issues with a solid wood panel (~20" wide), but there doesn't seem to be any.
In Temperate climates, one could expect 4-5mm expansion from such a board. On an oceangoing vessel, I imagine this would be greater.

Any thoughts?

 

[Fatboy]

It could be an earlier form of plywood?, the English were using plywood/laminated type construction from the 17th century, the Chinese a lot earlier than that.

 

[dzj]

True, plywood would be stable enough to not cause expansion problems.
If it is ply, judging by the cathedral patterns, it would have to be plainsawn.
20 inch wide veneer cut in such a manner is unusual. I imagine that in the 1800s they'd sooner use it
as an embellishment than for a back panel.