Considered one of the ultimate surviving plants, mesquite trees can thrive during just about any weather condition. Found typically in the desert, they tolerate heat, sandy soil and drought. The only thing they don't tolerate is overwatering. Mesquite tree owners often mistake dormant trees as dead or dying, even though the trees are hard to kill. It is easy to tell when one of these trees is dying because they have distinct signs.
Check the Bark
A sure way of checking if a tree is dying, or already dead, is to check its bark. Make a small, shallow cut in the bark of the tree and open the cut to check in the inner skin portion of the bark. If the skin portion of the bark is green, the tree is alive and healthy; if the skin is turning brown, however, the tree is dying.
Check for Dormancy
Wait until late spring to check if the tree was just in its dormancy phase. Mesquite trees are deciduous and lose their leaves during winter then produce new ones in late spring. Walk around the tree to check for signs that new leaves are sprouting and that the tree is also producing creamy-white flowers. If by late May, your Mesquite tree is still bare, it is likely dying or already dead.
Check for Problems
Check periodically for problems with your Mesquite tree. When inspecting your Mesquites, don't be alarmed is you see sap bleeding from the bark -- this is a sign of a healthy tree. If you notice the trunk splitting, this could be the result of the tree growing too fast and not a sign that it's dying. Mesquite trees live for more than 200 years, so do not worry about the tree dying of natural causes.
Mesquite trees should not be overwatered, as this is one of the things that could cause this type of tree to die prematurely. Overwatering causes them to grower faster than normal, which causes an overly large crown and a weaker trunk. Watering a Mesquite less often and performing a heavy pruning is a remedy for the tree's tendency to split from growing too fast. Giving Mesquite trees a deep watering every two to three weeks during the summer months is the recommendation from Rod McKusick, a Master Gardener at the University of Arizona.