Question
We live in Arizona at about 4500 feet elevation and have two 35+ year old fruitless mulberry trees.  One is just fine.  The other has some limbs with little or no leaves.  There are a few five (5) inch cracks in the bark.  Around the tree mushrooms want to grow.  Have spread a dusting of gypsum on the grass around the tree.  What else should I do to save my tree?  Thank you for your help.

Answer
Roberta:
It is difficult to make an assessment w/o seeing your tree in person.  One of the trees sounds like it is declining for one reason or another based on the appearance of dead limbs without leaves.  The mushrooms that you mentioned MAY be associated with a tree root disease or just occurring cosmopolitan- i.e. growing on buried organic material in the soil and not related to a disease like root rot.  The bark cracks may also indicate a stressful situation for the tree. I wish there was a magic bullet, but unfortunately the only thing that you can do is try to prolong the life your tree by good fertilization practices, maintaining a consistent and adequate source of water and preventing any injury to the tree by damaging the bark or roots.  

I suspect that there may be some level of internal decay within your tree, causing the dead branches.  This is irreversible, but often quite slow if the tree is cared for properly.  A tree can hang in there for several more years.  At some point the tree becomes structurally/physically weak and may fail.  Often this occurs during a wind or ice storm in which branches or whole trees may fail.  As more and more branches die and the tree health continues to worsen, it may be time to remove, but until then, enjoy your tree and be sure to maintain good watering schedules during hot/dry conditions. I suggest a visual evaluation each spring to see how well the tree fills out its leaves.  You may wish to consider contacting a certified arborist (see yellow pages)to make a "house call" and evaluate the overall health status.

Regards
Steve