Are soil-based carbon offsets better than forestry? Over the years, various carbon markets came under fire for greenwashing claims, including those related to forestry-based carbon credits. Forestry-based carbon credits are considered “a cheaper type of credit,” since carbon is stored in the biomass, which “is not necessarily permanent,” Grotsky explained. Most of the carbon, probably north of 70% of the carbon, that is sequestered by mycorrhiza becomes mineral-associated organic carbon. They need a portfolio, and so a large carbon trader like Anew Climate can offer that portfolio and can get our credits out the door.