BOB Downie uses some creative accounting in putting forward his case for the better fixing of carbon over time of a field of trees in contrast to a field of crops (Letters, February 3).

Conceding, as he does, that a field of either fixes a similar amount of carbon, it matters not a whit, contrary to what he states, that, whereas the trees hang on to fixed carbon for a longish period of time, the crops rapidly yield up their carbon intake to the environment. He ignores the fact that the successive crops will be fixing as much carbon as their predecessor crops have yielded up. Thus in the long run crops tie up similar amounts of carbon from the atmosphere as the trees.

Swings and roundabouts, Mr Downie, swings and roundabouts.

Darrell Desbrow,

Overholm, Dalbeattie, Kirkcudbrightshire.