skilltree.chat - required to use the chat commands to access the skill tree menu.
skilltree.xp - required to obtain xp from xp sources.
skilltree.tree - required to access and use the skill tree.
skilltree.admin - required to use the admin commands.
skilltree.all - allows user access to all trees.
skilltree.Mining - allows the user to access the mining tree.
skilltree.Woodcutting - allows the user to access the woodcutting tree.
skilltree.Skinning - allows the user to access the skinning tree.
skilltree.Harvesting - allows the user to access the harvesting tree.
skilltree.Combat - allows the user to access the combat tree.
skilltree.Medical - allows the user to access the medical tree.
skilltree.Build_Craft - allows the user to access the build craft tree.
skilltree.Scavenging - allows the user to access the scavenging tree.
skilltree.Vehicles - allows the user to access the vehicles tree.
skilltree.Cooking - allows the user to access the cooking tree.
skilltree.bag.keepondeath - prevents the ExtraPockets bag from dropping on death.
skilltree.notitles - Removes the level title from the player (Requires BetterChat)
skilltree.noxploss - Prevents xp loss.
skilltree.roguelike - If enabled via the config, will be required to participate in the Roguelike system.
skilltree.teabonus - Ignores the config option preventing the yield increases from working with mining and woodcutting teas.
skilltree.noscoreboard - Prevents players with this permission from being added to the scoreboard.
skilltree.respec.bypass - removes the cost for respeccing
skilltree.togglebc - required to toggle BetterChat titles on/off
I recommend using a permission manager if you aren't already. Shows you exactly what perms each plugin has registered.