A California startup is pursuing a novel, if simple, plan for ensuring that dead trees keep carbon dioxide out of the atmosphere for thousands of years: burying their remains underground.  Kodama Systems, a forest management company based in the Sierra Nevada foothills town of Sonora, has been operating in stealth mode since it was founded last summer. But MIT Technology Review can now report the company has raised around $6.6 million from Bill Gates’s climate fund Breakthrough Energy Ventures, as well as Congruent Ventures and other investors. In addition, the payments company Stripe will reveal on Thursday that it’s provided a $250,000 research grant to the company and its research partner, the Yale Carbon Containment Lab, as part of a broader carbon removal announcement. …A handful of research groups and startups have begun exploring the potential to lock up the carbon in wood, by burying or otherwise storing tree remains in ways that slow down decomposition.