Alder is a deciduous tree and when cut, gets it´s characteristic red colour naturally. It is great for smoke-cooking due to the gentle aroma which develops in reasonably low temperatures.
Soak the chips in cold water while your grill warms up, for a half an hour or so. When your cooking is almost done, thrown a small handful of drained chips (avoid excess water) on the coals, cover your grill and your food gets a delicious smoky finish in just a few moments.
PS. Alder is an excellent choice for use in smoke-ovens as well