Question
I have some pine trees 10-12' tall, that were transplanted 6-8 months ago.  Their appearance is somewhat yellowish compared to when they were planted.  The area is high desert northern Nevada.  What are the signs if they are getting enough/or not enough water.  What should the watering schedule be?

Answer
Sounds like more of a lack minerals rather than water. If the soil PH is too high then the nitrogen and other minerals (iron) are tied up and the roots a can not absorb the minerals.  

In areas where the PH of a soil exceeds 6.5 (alkali soils), iron is tied up in the soil and unavailable to the trees. Lack of this essential tree nutrient results in partial or complete yellowing of the leaves (chlorosis). In severe cases, it causes browning and/or shedding of leaves.

Resolving iron deficiency problems can be accomplished by:

*applying a fertilizer with high sulfur-iron concentrations

*injecting trees with a solution of iron salts or

*spraying tree foliage with a solution of ferrous sulphate

Check with your local nursery from these products. They can tell you at the nursery how much to use based on the size of the trees. If you can get it a soil test will give you the information on what is needed to be added to the soil to balance the PH. The nursery should be able to point you in the direction on soil testing.