This is possibly a longevity board, intricately caeved that is Chinese. It measures 36 inches X 36 inches. There are a few surface scratches on the border or edge.
This came from an antiques faire sale of various vendors.
I am not familiar with the term 'longevity board’, what's that?
This is a Chinese carved window panel. The character in the middle is 茶，meaning “tea”.
Here are some similar pieces with hammer prices, to give you an idea of the market. The fair market value of your item is between $100 and $300 based on sales of similar items.