Before Ekade goes crazy off Serets post...let me enlighten you. Unless you've done more then 10 holo professions, then your only going to get one free tree unlock. I dont know how Seret did it having only worked on and not masterd it. I was one block from master merchent (Which was my first and only holoprofession) before I trashed it, and I recieved no holo credit. Yala did 17 professions and unlocked 4 trees with 1 tree being given to her by the entrance quest for a total of 5. So unless you have more then 10 professions masterd...dont expect alot of tree gain. Thats what was given as info on the Jedi forums. If you dont believe me...look it upSeret Sajet wrote:Also any holo professions you may have ground up will help you out.
Last night I was able to train in Melee Speed under Combat Prowess all the way up to level IV. That gives me +12 speed to ALL melee professions I have. Now I am a Swordsman to be reckonned with. Woot!
This is because I must have ground at least one Holo profession. Now mind you I haven't mastered any on purpose. The only holocron I opened said Creature Handler and while I was one for a bit I never mastered it. On the other hand I have masteres Swordsman, Commando, Marksmen, Artisan and Scout. One of those must have been one of my holos.
Having done holo professions means two things for you:
-You get enough experience for one tree
-You unlock to skills to train in without having to wait for new quests to spawn in the cyclical timline of the town.
What does this mean?
You get the FS XP by trading in your current XP for any profession but you can only train once you do a specific quest for a specific person in the town. For example, I did the quest for the Captain of the guard in town and was able to train in Ranged Accuracy. If you do missions for Whip you can train in the Enhanced Reflexes tree. Get the idea? Having Holo professions done means you don't have to wait for different NPCs to spawn and do their missions.

Dont get your hopes up to be let down if you think your going to be padawan overnight unless you did an extreme amount of profession grinding. Also remember that you have to still get the XP to fill the blocks. This goes for anyone who did hologrinding but stopped with less then 10 professions done. You may be on phase 2, but thats gonna be about as far as your at.