Al Breed replies: It depends on what you are turning. If you need strength without detailed ornament use a strong wood like oak or hickory. If you want a turning that will take a lot of detail without breaking at the fillets, use maple, birch, mahogany or another fine grained wood. Basically ring porous woods will not hold detailed elements without breaking.
A wood like pine is good for turning but will be easily damaged and is not strong enough for small scale work, but is good for large architectural elements that get painted.
Jon Siegel replies: Wood with distinct hard and soft layers can cause problems for the woodturner. Most noteworthy in this category are douglas fir, yellow pine and redwood. These woods tend to become lumpy when you sand them because the soft layers wear away so much faster than the hard parts. The solution is to sand less, but it can be difficult to obtain a good finish from the turning chisel because of chipping adjacent to the soft layers.
An extremely light cut with a perfectly sharp chisel is required for good results. Even ring porous hardwoods, such as oak and ash, can cause similar problems. Conversely, the best woods for turning are the diffuse porous smooth textured woods such as maple, birch, beech and cherry.
Brad Vietje replies: I would avoid any wood that presents a danger to you, or to your audience, if demonstrating. This would include unsound wood with discernible cracks that might fly apart during the turning process. I recommend a careful inspection for cracks and voids, and turning a questionable piece slowly until the soundness of the wood can be judged. When turning wood with bark inclusions, rotten areas, or voids, do not stand in line with the spinning wood. Lathes that allow the turner to turn outboard or otherwise stand off the end of the lathe, out of the firing line, are best for any questionable turning blanks, as the wood will usually fly away from you if it blows apart.
When demonstrating, avoid woods that are likely to cause problems to others. This includes the more toxic species, such as walnut or exotics, like the rosewoods, to which many people develop allergic reactions, as well as spalted wood. These woods should only be handled when all lungs present are protected by dust collection and respirators.