Question
Hi Dr. Vann,

I need to ask you a follow-up question to the question I asked you a few days ago at this link, http://en.allexperts.com/q/Plant-Diseases-715/2013/9/chinese-pistache-tree-dying.  
I noticed yesterday sap leaking out of the bark.  I have included a few photos of this.  This is happening all over the tree.  I don't see any holes at the base of the tree or higher up on the trunk that would indicate an insect burrowing in.  A couple of years ago we had a bad storm with golf-ball sized hail that damaged this little tree as a sapling.  Does the leaking sap and dying leaves connect to a common problem?

Thanks,
Tim Elliott (links to photos below)

http://www.flickr.com/photos/27657351@N07/9717572066/
http://www.flickr.com/photos/27657351@N07/9714340519/
http://www.flickr.com/photos/27657351@N07/9714341047/
http://www.flickr.com/photos/27657351@N07/9717572498/

Answer
Tim:
The exudation of sap in this manner is often associated with a wound.  The wound can the result of insect activity or just a mechanical/physical thing.  In your case, the droplets seem to be associated with a bark crack.  Is this the case or can these be found in areas where the bark is intact? Sometimes sunscald can create cracks, especially on thin barked trees.  Nothing to do in this case- just promote vigorous growth with appropriate soil moisture and fertilization practices (based on a recent soil test).

Regards
Steve