It is difficult to know what this might be without photos or a sample. If the tree has been recently injured, it will excrete sap so look to see if the sap is oozing from a cut or injury. If the sap is coming from one specific area, it also may be an insect infestation so you can look for holes in the trunk. If the sap is pinkish in color, it could be pitch mass borer insect. If the sap has a popcorn-like appearance, it could be Zimmerman pine moth. If the sap appears to 'rain' from all different areas, it may be from new cone development and the excess moisture we had this spring. You can check to see if there is sap around all of the cones. Finally, the 'sap' may not even be sap but rather 'honeydew' which is excretion from aphids.

If you can provide several good, detailed photos, that would help. Or you can take a sample to the Diagnostic Clinic at Arapahoe County Extension Office at
5804 S Datura St, Littleton, CO 80120; Phone:<personal data hidden>. There is a small diagnostic fee for in-county residents. Make sure the sample you bring is at least 18" long and is indicative of what exactly you are seeing on the tree.


Some helpful links for you:
http://www.ext.colostate.edu/ptlk/1456.html
http://www.ext.colostate.edu/pubs/insect/05591.html
http://www.ext.colostate.edu/pubs/garden/02948.html
http://www.colostate.edu/Depts/CoopExt/4DMG/Trees/natever.htm
http://www.ext.colostate.edu/pubs/insect/05528.html