Question
I have about ten twelve-year old well spaced alder trees located on a lawn in the high desert near Barstow, California.  A month ago (when the temperatures reached over 100 degrees for about a week) my sprinkler system failed when I was gone for about 7 days.  The lawn went brown (with a touch of green) and the trees lost 90% of their leaves.  The leaves went brown as if it was autumn.  When the problem was discovered I flooded everything in water.  The lawn recovered.  The trees look a tiny bit better, but have lost half of the remaining leaves and have grown what looks like seed buds to a non-horticulturist like myself.  Half the trees look as if they might die next year.  As tree roots are  deeper than grass roots I feel the trees must have been sick before the incident, and that the lack of water just made an underlying problem much more obvious. The trees have never looked particularly healthy, but I have seen many look much worse, so I just thought it was the desert climate.  What should I do?  Is there a fertilizer I can try, now? or in the Winter or Spring? How do I get the problem analysed?  I do not have photos, but I can get some, if that would help.

Answer
When a hardwood tree is cut off from water in the summer they will shut down and drop their leaves. When water is replaced they will usually leaf out again. Sounds like what has happened in this case. I would water with 1 inch of water- place a pan under the tree and turn the sprinkler on and when the pan has 1 inch of water in it stop. Do this every fourth day for a month and then once a week. The tree should leaf back out. I would not fertilize it until next spring. If it does not leaf out check to see if it is alive by starting near the end on an upper outer branch and scrape a small bit of bark off and if the color under the bark is green the branch is still alive. If the color is brown continue down the branch scraping at intervals until you find green. It should be green but any not leaf out this year if so continue watering if it does not rain and see what happens. It should leaf out.v