Cedar is not recommended for smoking meats. Please read below for explanation.
Bad wood. Whatever you do, never use wood from conifers such as pine, fir, cyprus, spruce, redwood, or cedar. They contain too much sap and they can make the meat taste funny. Some have been known to make people sick. Yes, I know that cedar planks are popular for cooking salmon on, but I don't know anyone who burns cedar as a smoke wood. I have also heard that elm, eucalyptus, sassafras, sycamore, and liquid amber trees impart a bad flavor. Never use lumber scraps. Some lumber is treated with chemicals that are poisonous. Never use wood that has been painted. Never use wood that is moldy.