Definition of "leafy"

Those are not necessarily the leafiest areas. From the tenants of Durham, £1,671,546 was used to subsidise people elsewhere. I am not familiar with Durham, it may be a very leafy place in the north-east, but I suspect that there is a need for those funds.

2008 January 23, Robert Syms, “Housing and Regeneration Bill: Exclusions from Subsidy Arrangements”, in parliamentary debates (House of Commons)‎, column 392

Income tax payments cost the average British taxpayer £4,985 a year, but those who reside in the leafiest areas of the country pay three times this amount.

2014 July 21, Kyle Caldwell, “Income tax league table: the towns that pay the most and least tax in Britain”, in Daily Telegraph‎

The Tories plan to give their all against the other Ukip defector, Mark Reckless, in the more prosperous Rochester & Strood next month. But this plays to the stereotype: Tories fighting for leafy areas, hiding from the poorer ones.

2014 October 10, Fraser Nelson, “Clacton by-election: The Tories cannot fight for leafy areas and forget the poor”, in The Guardian‎