It will burn fine, but you must split even the smaller wood, the bark on hemlocks as with all pines has a fire retardant in the bark, to protect it in a forest fire.
Several years ago I had some scotch pines I cut to burn. I did not split them if they were over 4" diameter. When I put some into a roaring fire every other thing burnt up and at the end of the day, I still had a 4" chunk (Scotch Pine), blackened but still full size.
Dave Klish, I recently ordered a 2x6 wood fired evaporator from A&A Sheet Metal which I will be converting to oil fired
Now have solar, 2x6 finish pan, 5 bank 7x7 filter press, large water jacketed bottler, and tankless water heater.
Recently bought another Gingerich RO, this one was a 125, but a second membrane was added thus is a 250, like I had.
After running a 2x3, a 2x6, 3x8 tapping from 79 taps up to 1320 all woodfired, now I'm going to a 2x6 oil fired and a 200-425 taps.