Several hours before building an open fire on the beach, cut green alder branches to form the cooking rack. You will need a four-foot piece of green alder approximately  3 inches in diameter for the backbone of the rack. For the ribs that will keep the salmon in place, gather 14 to 16 alder branches each the diameter of a pencil and about a foot long.

Sharpen the largest end of the big alder branch into a point. About a foot along the alder branch from this sharpened end, wrap soft iron wire around the branch, securing it tightly with pliers. Starting at the opposite end, saw the alder branch in half lengthwise. Stop 3 or 4 inches from the wrapped wire.

Slip the boned salmon between the halves of the large split branch, leaving a fillet on each side. Place a couple of the smaller alder branches on the salmon fillets parallel to the large stick, then place more sticks perpendicular, passing them through the split. Repeat on other side of salmon so the sticks create a supporting grill on each side. A twist of wire at the top of the split central stick will hold the framework and fish securely even in its upright cooking position.

Lay the framed salmon skin-side down on a large piece of aluminium foil or clean tabletop. Sprinkle the flesh evenly with salt and black pepper. Rub brown sugar through a metal sieve over the fish, coating it well. Let the fish rest in a cool spot until ready to cook.

Build a good-sized wood fire away from the wind. Once it's starting to produce hot coals, put the sharpened end of the large alder branch into the ground,  standing perpendicular to the fire. As the fish cooks, rotate the branch several times. A fish of 5 to 10 pounds will take 45 minutes to an hour to cook. Add wood to the fire as needed. To remove the frame, lay the cooked fish in its frame on a flat surface and remove the end-twist of wire. Serve.