Answer: Without more detail, it's hard to say exactly what is going on, but it sounds like a soil moisture problem. Dry conditions, especially on newly planted trees, can cause needle browning and drop. Other possble causes include needle blights (fungal diseases that are often brought on by frequent wetting of the foliage and which can be managed with fungicide sprays), or possibly an attack of mites or other pests. Look closely along the branches. Do you see any insects?
Your best bet is to take a sample to your County Extension Office to see if they can help diagnose the problem and recommend an appropriate course of action. Good luck!
Q&A Library Searching Tips