Question
I have two apple trees and one has not blossomed at the top of the tree, on the dead branches is a light green/gray substance. It is also starting to grow on the other tree and on to the leafy branches. We also have tall spruce trees in our yard where it has formed and they are rotting and falling down. You can actually pull the bark from the inside of the tree; which is black inside. This substance is travelling through our yard and I have also noticed it on my lilac tree. I live in Spruce Grove Alberta on an acreage. Do you have any idea what this substance may be?

Answer
Jodi:
Is this substance leafy or crusty-like and grows on the bark?  If it is, it may be LICHENS.  Check "Google" Images and seach for pictures of lichens.  If it is, these are not the cause, these things usually show up on older and stressed trees.  They do not harm the trees, merely along for the ride.  There is some other factor causing the stress- perhaps some level of internal decay.  You are welcome to send me a closeup (get real close) digital image if you still have some doubt.  Just be sure to review the photo on your computer before you send it- to be sure it is in focus.

Regards
Steve