Evergreen Tree Problems 1 of 2
We have an evergreen in our front yard. It is about 50 feet tall. In the last 4 years it has slowly died. A branch begins to die from the center to the end. It is often replaced by a lichen looking material. Eventually the branch becomes bare. You can see this lichen material in the picture ending in 7 - at the bottom of the picture.
Montgomery County Maryland
Lichen is harmless to trees. It merely uses the tree for support but is not a parasite. However, it can be more prevalent on declining trees.
We cannot say from the photo what has caused the deterioration of your spruce. However, it has a lot of dead material towards the top, which is not good. There are no signs of a disease or insect infestation. It may merely be a very old tree that is being out competed by other trees.
Please read through this page: http://extension.umd.edu/learn/how-do-you-decide-when-remove-tree