Additive addition (a). Poplar presented difficulties during pelletization
because it is a tough material, and in fact, vibrations were
observed in the pellet press during the tests. Different percentages
of additives (1 and 2 wt.% d.b.) were added to improve the process
to obtain pellet with ENPlus quality. No additives were used with the
blends because the pine content helps the pelletization of poplar
blends.