Artificial trees are being looked at to cut CO2 emisssions.  Why don't they don't plant real ones instead, decentralise sewage treatment  and install BIOROCK plants? An acre of trees removes 2.6 tonnes of CO2/year.  If they did this in the UK it would be equivalent to saving the CO2 absorbed by 46,000 acres of UK woodland.  http://news.bbc.co.uk/1/hi/sci/tech/8223528.stm