Yes in the islands they place the meat on the wood and then cover with metal. The wood acts like a cedar plank, helping to give the chicken or pork flavor. But they also use the wood for the coals and even add leafs of the Pimento tree to create more smoke.
I think using the wood as chunks will give the Jerk a bit more of the traditional flavor, but the test will tell
Besides you can never have enough wood!
Here is a video using a charcoal grill, where the cook talks about the smoke.
https://www.youtube.com/watch?v=7WRv6wIqMY8Greg
