they are purified air — so air without c02 or with very little c02 — leaves the box. when the filter�*s full, we close the door and start heating. we heat up the collector up to 100 degrees, c02 is released and we take it out. once the filters are cleaned, the carbon capture can start all over again. perhaps one of the best technologies at solving the carbon problem is nature itself. i've come to brynau wood in south wales, one the last patches of a once enormous ancient woodland. today, a reforestation project is under way. many countries have committed to planting more trees to soak up c02 but my guide gwyn says the mix of trees planted is crucial to success. when there is a mixed amount of tree species within a forest, so the more biodiverse we have in terms