A ___________of Arborists

[Tom Dunlap]

Everyone has heard of the collective nouns for various groups. Take a look here:

http://rinkworks.com/words/collective.shtml

Along those lines, there are collective nouns for occupations. What is your occupation and what would the collective noun be?

These are some that came from the Patrick O'Brain forum:
A brief of lawyers
A rash of dermatologists
A stream of urologists
A tally of accountants
A breath of pulmonologists

Here's one I thought up:
A shift of truck drivers

Now, what other one's are out there? I have a couple for arborists but I'll bet that someone else will come up with the same.