Question
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Followup To
Question -

Thank you for your quick reply.  Amazing!  I assume aphids propose no danger to tree.  I must say I became determined to find an answer to this question today, because my sister's tree (also a maple) fell yesterday and nearly missed her car.  Turns out the city said it was hollowed out by carpenter ants.  I was happy to find this site and glad my tree should not be in danger.  Just as an FYI is there anything I should look for to avoid the problem my sister had?  How would anyone know?  We do happen to have a squirrel's hole in the trunk just beneath a "V" split where the trunk turns into two.  I've considered having it inspected, but I am not comfortable thinking I might get taken by a company looking to chop anything down for a profit.
Sincerely,
Ann

Your maple tree has aphids and the sticky stuff is "honeydew".  Aphids feed on the sugars produced in plants and transported in the phloem.  The phoelm is under pressure and when the aphids feed the pressure basically forces its way through the aphid and out it's butt.  It is this "honeydew" that drips on cars.  Then sooty mold grows on the "honeydew".  Very annoying.

As far as control goes there really is not any practical method and this can be cyclical as this is the first time you have had this problem after a couple of years.  

Don't let your husband cut this tree down.  Try parking in the garage.

Good luck

Gary

Answer
Ann,

Have a certified arborist inspect your tree.  Contact the Arboriculture Society of America for a list of these professionals.  Doing this will give you a good idea of what potential hazards may be present.  

Good luck

Gary

PSS:  Thanks for the kind words