Question
Our neighbor very graciously let us trim several branches from 3 oak trees and let us have 2 pine trees totally cut down so that we could get the full benefits of our new solar energy system which was recently installed on our roof. Two months have gone by and he just called to say that he thinks the pruning sawdust is killing his 2 year old cypress fence lining trees. We want to do the right thing, but our tree guy says that the sawdust did not and would not cause the trees to die, he seems to think it was either the incredibly tough winter we had killed the trees, or a fungus. The branches of 4 of his trees (all in a row) are turning brown. These trees were always smaller than the other trees on the fence line, probably because they did not receive as much light because of the pine and oak trees right above them. We want to do the right thing by our neighbor, but can sawdust do this to a tree? Help!

Answer
No the saw dust or chip will not kill the trees. I have heard of fresh chips causing the newly planted tree to turn a little yellowish from the nitrogen released fro the new chips but this did not kill the tree or cause a few branches to die.

Cypress have a few branch type diseases that can kill branches an sometimes tree. It could be one of two things Seiridium Canker and Twig Dieback or Botryosphaeria (Bot) Canker. The inner needles shedding is normal but needles on the outer parts of branches indicate something is wrong. Here is a web link that describes the two most common problems and their control. You will have to determine which you have from the descriptions. http://www.caes.uga.edu/Publications/pubDetail.cfm?pk_id=7067&pg=np&ct=leyland cypress&kt=&kid=&pid=