A 3,775-year-old log found under a Canadian farm may offer a simple method to sequester carbon and slow climate change. Despite its decayed exterior, the log’s core remains hard, suggesting that burying wood in the right conditions could lock carbon away for thousands of years. This method could be a cheap, scalable alternative to expensive carbon-capture technologies. Forests absorb significant CO2, but decomposition releases it back into the atmosphere. Delaying this decay by burying wood could help meet climate goals and prevent disastrous warming.