Dead trees keep surprisingly large amounts of carbon out of atmosphere

In N Stephensons “Anathem” there are “fuel trees” and a couple paragraphs describing how they are ‘cooked’ for hydrocarbon fuels. I like trees and his vision of a future where genetically modified trees are the best way to collect solar energy and then harvest and store it. Solar panels are cool but one of the themes of the book is civilization over many millennia, and I can see how he arrived at his conclusion that most tech doesn’t work as well as trees.

Sounds like that isn't far from the truth. Cooking wood in an anoxic environment creates wood gas and charcoal. Wood gas can be burned as it comes out of the retort or can be refined into methanol and other hydrocarbon fuels. The charcoal product is a high quality activated charcoal. That can also be burned as fuel or charged and put back in the ground as biochar.