Corn ethanol utilizes the starch from corn, and leaves behind proteins, fats, minerals, and yeast cells which are used as animal feed, where its superior to plain corn.
Likewise woody biomass isn't coming from clear cutting forests, its from necessary thinning to keep forests healthy (thats otherwise burned in slash piles) and mill waste thats a byproduct of lumber production.
From what I've seen, claims to this effect often turn out to be false. For instance, from https://billmckibben.substack.com/p/a-little-xmas-cheer-for-...:
> ...the world’s largest supplier of wood pellets for power generation ... has long insisted that it doesn’t use big, whole trees, but only uses wood waste, “tops, limbs, thinnings, and/or low-value smaller trees.” It insists it only sources wood from areas where trees will be regrown, and that it doesn’t contribute to deforestation.
> As it turns out, Mongabay reporter Justin Catanoso found a management whistleblower who pointed him in the direction of clearcuts that the company was making: Catanoso watched as a feller-buncher machine grappled down a fifty-acre forest and fed the old oaks straight into a chipper, producing tons of wood to be turned into pellets. The whistleblower said that was par for the course: “We take giant, whole trees. We don’t care where they come from. The notion of sustainably managed forests is nonsense. We can’t get wood into the mills fast enough.”
> He continued: “The company says that we use mostly waste like branches, treetops and debris to make pellets. What a joke. We use 100% whole trees in our pellets. We hardly use any waste. Pellet density is critical. You get that from whole trees, not junk.”