When deciding where you are going to place a mask or sculpture consider how much direct light will hit the object. Of course you don't want to hide your favorite art work in some dark corner of an unused room. Try to find a place that is bright but does not have prolonged exposure to direct light. A moderate amount of indirect light over time will give most wood objects a beautiful pitina. This gives the object a very desirable aged effect.
Humidity can be a problem.
Cedar is a very water resistant wood that also retains it's own inner moisture. It can take years for a large piece like a totem pole to completely dry out. The wood dries faster on the surface of the piece while the inside of the wood remains wet. The inner moisture is released through these checks allowing the wood to close back up when it reaches an even dryness. Great care needs to be taken when carving to ensure that these checks remain clear of sawdust so that when they close no obstruction impedes them.