This is a bonus guide where I play around with the "effective range" of siege weapons (trebuchet and catapult) based on in-game play and A LOT of speculation. This bonus guide is in NO WAY meant to be an accurate portrayal of actual game play... take it for what it's worth... nothing more.
There are two parts to this bonus guide as I rambled on for a lot longer than I planned!
Mistake - the "Book" icon in near the Broken Hearts are not the Commander Book vendors, but rather Traits trainers (they reset traits for you for a price). My mistake...
Additional Consideration - in talking with the folks from Guildwars2 Guru forums, Mathjoh and others were thinking perhaps HEIGHT might make our siege weapons fire a bit further... So, again to qualify, my measurements were based on in game observation, and YES, my catapult and trebuchet attacks were made from a significantly higher altitude than our target! Next beta... I will have to do some major testing! (in no way am I promoting the mentioned forum, just giving credit where it's due).
Bonus Guide - PART 2 of this Video!