Most of the surviving medieval furniture in central Europe has been made from oak. This does not mean that all medieval furniture consists of oak; oak is just a wood type that can withstand the test of time easily. Most of the medieval furniture from the Alpine and Scandinavian regions on the other hand is made from softwood like pine and fir - these are the common wood types from these areas. In northern Italy, walnut is a common wood found in medieval furniture. There have been surviving examples of medieval furniture made from softwood, like some chests in the convent of Isenhagen in Germany.
A 15th centrury archive cupboard from Hagenau, France made from fir wood.
This year we found another example in the Historic Museum in Hagenau, France. It is a small fifteenth century archive cupboard made of fir wood that used to belong to the Saint George church in this city. The cupboard is painted with black motives on the front and sides. Most interestingly, the centraL motive appears to be a medieval turned chair! 
The side of the Hagenau cupboard. Boards continue on to the floor.
The central motive is a medieval turned chair.
Most boards are nailed, but the top of the cupboard is fastened with dovetails. It is unclear how many shelves the cupboard had, as no nails indicating them are recognisable from the outside. The cupboard has 2 doors.
The top board is fastened with dovetails.
The bottom front board is nailed. The black motives continue from the doors to the bottom board.
A thin rail reinforces the boards of the doors. The hinges are placed over these rails. The cupboard has two similar looking primitive sliding locks. The bottom lock was placed too low, and some parts of the thin rail had to be cut out to accomodate the decoration (and fastening nails) of the lock. Some of the wood near the upper lock has been gone; this enables us to see the the bolt hole for the sliding bar of the lock.
The top sliding lock.
The corresponding bolt in the other door for the sliding bar can easily be seen.
The lower lock, with the cut out pieces of the supporting rail.
