First find a suitable tree!
Maple, more specifically, Acer Pseudoplatanus; or Sycamore, Is the wood of choice for violin backs, ribs and scroll. It has a good strength / weight ratio, and as a bonus, comes in a variety of pleasing patterns. The “Flame” which runs across the direction of the grain, is caused by the tree fibres growing in a wavy pattern. Highly flamed wood looks more attractive, is more expensive, is more difficult to come by and is more difficult to work with because of the variable grain direction. It can also be stronger. The curly fibres act as a rip stop. Sycamore which grows in mountainous or colder regions usually has the growth lines closer together. This makes for denser, stronger wood which can be made into thinner, more responsive, backs and ribs.
Sycamore is not native to Britain, it is believed to have been introduced from Europe sometime in the Middle Ages, and to gardeners, it is almost as popular as Himalayan Balsam and Japanese knotweed. Other types of wood which are used for violin backs, necks and ribs are Beech, Poplar and Pear wood. Poplar is softer, Poplar and Pear are both less stable than Sycamore.
A ‘Cello Back, one piece violin back, and several other sections to be converted into Violin/Viola Backs. All from the same Sycamore tree I found in 1984, already cut down, in a park less than a mile away from my home in Scotland. A couple of meetings and 'phone calls later and I had two 40” tall lengths of tree trunk with a diameter of 26” delivered to the door. I have so far made a ‘Cello and a Lira da Braccio from this tree
The front of a violin is usually made of Pine. Sitka spruce, (Canadian), Picea Abies (Norway spruce) and Picea Glauca being some of the favourites
The best wood for the front will have regular grain lines and will be quarter sawn. Preference for the width of the grain lines tends to vary with the mood of the maker or the nature of a commission. For a warm sonorous sound I would choose wood with slightly wider grain lines (softer ) But for a brighter sound, to be heard over an orchestra I would choose a denser wood with the grain lines closer together.
For bridges with a good sound transfer from string to instrument, I would choose Sycamore with very tight grain and prominent medullary rays.