Simon Withers (09.05):

The Office of National Statistics "Environmental Accounts 2004" report
informs us that:

http://www.statistics.gov.uk/downloads/theme_environment/Environmental_accounts_2004.pdf

"Within the UK the number of trees per hectare varies, however in 1999 there
were a total of 3911 million trees in the UK, representing 67 trees for
every man, women and child in the country."
I rather like the idea that somebody is out there conducting a tree census
every ten years or something.