I have been watering this tree about three times a week ever since it has gotten very hot here in Texas (90+ days for about month now).

I noticed a lot of leaves are yellowing... and my lawn is filled with fallen yellow elm leaves.

I noticed there is clear sticky sap coming out of the bark in some spots.

Any advice would be greatly appreciated to help save my tree.

Please click link below to see some pictures.

http://www.evernote.com/l/AW51JsrSvD...fMjWfZwHzc-Pc/

The gum coming from the linear, diagonal lesion, under loosened bark plates, is a likely sign of fungal attack in the "sap stream" region of the trunk. The food manufactured in the leaves is heading to the roots to feed them. The fungus is (perhaps) cutting the flow, starving the roots, causing the leaves to drop. Where I live, infections such as this (may be) are usually a result of broken limbs or weedeater damage at the base. See if there is a plant pathologist available from the extension service. There may be no practical treatment once leaf drop has occurred.