[R] Word cloud based on a specific site

[Marcelo Laia]

Hi,

I would like to do a word cloud in a specif site related to a specific
word.

For example, I could be interested in discovery what are the words
linked to word "tree" in a site like www.foo.bar and have the result in
a wordcloud image.

Please, someone could me point me out a package or a bibliography or
tutorial or somethings else?

Thank you so much!

-- 
Marcelo