Production of wood pellets from Alaska-grown white spruce and hemlock

An extensive literature review failed to locate any information relative to the pelleting characteristics of hemlock species--western hemlock (Tsuga heterophylla (Raf.) Sarg.) and mountain hemlock (Tsuga mertensiana (Bong.) Carr.)--that grow in Alaska. To determine more about the pelletizing properties of the species, arrangements were made with a pelleting company to conduct test runs using mixtures of pure Alaska-grown hemlock and combinations with white spruce (Picea glauca (Moench) Voss). The test runs were conducted by using the same methods and procedures that the firm had been using in the production of white spruce pellets. The initial tests with Alaska hemlock resulted in pellets that were visually similar to those that the firm had been producing from spruce. Laboratory testing indicated that pellets made entirely of Alaska hemlock, or of Alaska hemlock and spruce mixtures, met most 2008 Pellet Fuels Institute (PFI) premium pellet and/ or standard pellet specifications, with a few exceptions. Given recent (October 17, 2010) changes to the PFI pellet specifications, pellets made entirely of hemlock, or of hemlock and spruce mixtures, could meet all premium pellet specifications with minor adjustments to the manufacturing process.