[dredmorbius]

In the case of wood, the carbon is accessed from, and ultimately returned to, the active biosphere. It's not fossil fuel that's been sequestered for 100s of millions of years, but was itself captured largely within recent decades.

Contrasted with burning coal, oil, or gas, preferred.

(Woodfuel may still be burned unsustainably, that's a separate question.)

Noted FWIW in TFA:

[U]nlike gas and oil, wood is a renewable and CO2-neutral fuel (the CO2 that is produced by the burning of wood was taken out of the atmosphere by the tree during the years before). The problem is that wood stoves are not very efficient, and extremely polluting.