The goo is probably from the millions of aphids that will congregate on the tree in the summer. You would also probably see a steady stream of ants busily tramping up and down the tree �milking� the sticky secretion. There is a strong movement currently (rightly) to preserve urban trees, as too many have been felled after being wrongly blamed for property damage. Get on to the council, after all you pay their wages, explain your situation, tell them you love the tree, but can you have it lopped to a reasonable size. This would help with the �leaf situation�. I would bet the tree was there long before you moved to the house��don�t hate it, get to love it and all it�s inhabitants!