I believe the down voter based their action on the content of the answer.  There are a number of points which are incorrect or highly speculative:

- lichen [does not indicate a sick tree][1]
- a close examination of the photo does not show any ivy that I can see
- whether the "whole forest looks sick" is hard to prove from a photo
- there is no sign of charred bark on the tree

It is very difficult to do diagnosis on the basis of a photo and a few words.  Even when I did on site diagnosis for trees a lot of the time the root cause of any decline was not obvious.  My method for answering these tough questions is to only comment on what can be referenced from the photo or universities/colleges.

At the end of the day you can't please everyone.  Look at this down vote I got [here][2] from answer which attempted to describe the qualities of a good product. As Tea Drinker says don't take it personally.


  [1]: http://aces.nmsu.edu/pubs/_h/h-167.pdf
  [2]: https://gardening.stackexchange.com/a/7156/499