Well being from Alaska and a Alaskan Indian i can tell you that the Alder wood that Atz Lee used is the same my Grandparents and my great Grandparents used for as long as my Tribe can remember.
What was not shown is how long or the great detail that goes into smoking the fish , I remember my grandma and grandpa smoking salmon for 4 to six days but that also depends on how full the smoke house is. and if the fish is used to feed the sled dogs or if it was for human consumption.
Alder wood is used to smoke fish and also to make "dried" fish , it gives the fish a great and wonderfull taste.
you can get Alder wood chips from BassPro , i use it for Salmon but can never get the fish like my grandparents did .
As is with all Arts, smoked fish is a lost art in Alaska and the "fish" you can buy is not even close to the real smoked fish that you can get from one of the elders in Sitka or from one of the surrounding communities but you have to get it from one of the few elders that are willing to sell it.