Thank you for your question regarding discharge on your Pine tree. White Pine Blister Rust is one challenge met by pines that has the symptom of increased secretion of sap on the tree. You do not mention if there are other symptoms of decline (loss of needles/limbs, die back on limbs, etc.) an I am unable to tell from the picture you sent. What is present on the picture does not appear to be a healthy tree. I have attached a link to University of Minnesota information on pine problems that has symptoms and pictures you can reference. I would recommend you contact a local tree company and request a Certified Arborist come out and take a look at the tree.


http://www.extension.umn.edu/garden/diagnose/plant/evergreen/pine/branchesresin.html