The process of cooking on wood does intrigue a lot of folks.

First I woulde recommend that the cedar plank be soaked prior to using. This in itself will not be a measure to retard ignition but it does affect the flow of aromatic oils in the wood which impart the unique flavoring.

There are two things required for combustion heat and fuel. The planks generally do not ignite when used with a covered grill at a setting less than high. You will notice the tendency of the cedar to ignite whenever the lid of the grill is opened. When the grill lid is down it reduces the amount of oxygen and therefore retards the combustion process. Most people tend to want to observe the planking process and consequently keep opening the grill lid. That is when you can observe the plank to start to burn at the edges. When that happens it is necessary to use a spray bottle to extinguish the flare up. To prevent flare ups some users use the indirect method of planking which is nothing more than having the board away from being in direct contact with the heat source.

I hope this answers your question and of course if you are smoking meats in a gas, electric or bricket smoker the same applies as the gas grill mentioned above.