Blushingsnail, I feel that all trees in London are important whether I can see them or not, since they are part of makes up where we live. John Donne sums it is up very well in his famous poem

"No man is an island, entire of itself
every man is a piece of the continent, a part of the main
if a clod be washed away by the sea,
Europe is the less, as well as if a promontory were,
as well as if a manor of thy friends or of thine own were
any man's death diminishes me, because I am involved in mankind
and therefore never send to know for whom the bell tolls
it tolls for thee. "