That would mean that wood pellets are still much better than coal. The study cited in the article are saying essentially “wood pellets bad because solar and wind are better energy sources”. I agree with that statement, but the study also essentially says “coal is worse that wood pellets”.
Wood pellets aren’t generally made from trees turned right into pellets. The inputs are usually waste wood products from paper pulp making, agricultural waste, and wood scrap from other industries. There is certainly some extra energy input from hauling this material and pelletizing it, but stopping use of wood pellets isn’t going to save trees or reduce carbon emissions. Those dead wood inputs are going back into CO2 during degradation in the next few years or decades if they are pellets or not.