Can I do anything about yellowing and dying branches on my evergreen tree?
Weather conditions, age of the plant, genetics and geography all contribute to when needles drop. If the yellowing is occurring on the interior of the plant at the tips of the branches, it is healthy and normal.
Look at the buds at the end of the branches. According to David Robson, Horticulturist, "If the buds are plump, slightly green and covered with whitish to greenish scales, the tree should be okay. If new growth is weak or turning brown, root injury or canker disease may be involved. This summer’s growing conditions placed trees under lots of stress resulting in browning of needles."
Source: David J. Robson, Extension Educator, Horticulture
