The origins of the word "treenware" are not clear, but it probably comes from the Old English and refers to the plural of tree; "treen". Thus treenware was (perhaps) originally a reference to anything made from trees. In more modern usage treenware is small wooden objects used for practical purposes around the house. Some folk limit the term to kitchen use, others, like me, widen it to anywhere in the house.
In any case these are useful items made from wood.