Create a brine by combining brown sugar, salt, 1 tsp pepper, and 4 cups of water in a large bowl. Stir until dissolved and submerge salmon completely. Cover and refrigerate for 2 hours.
Soak the cedar plank in water for at least 1 hour. This will prevent the wood from burning on the grill.
Preheat the smoker to 250°F.
Take the salmon out of the refrigerator about 30 minutes before smoking, rinse, and pat dry with a paper towel, then season with salt and pepper
Place the soaked cedar plank on the pellet smoker and close the lid. Let the plank heat up for 5-10 minutes.
Place salmon skin-side down on the cedar plank and smoke for about 40 minutes, or until it is easily flaked with a fork.
Once the salmon is cooked, remove the cedar plank from the smoker and let it cool for a few minutes.
Serve with lemon wedges and fresh herbs