Don't fall into the trap of calling CO2 pollution, it's a greenhouse gas.
From the article:
A new study has found that wood-burning power plants using trees and other "biomass" from New England forests releases more greenhouse gases into the atmosphere than coal over time
To be fair wood is considered carbon neutral at least if you're just considering the wood itself and you can sustain what you're burning with new growth. If you have a tract of land that could supply enough wood indefinitely because of new growth you have a natural carbon capture system. You have a cycle where you are burning and creating CO2 but the new growth is also capturing that CO2.