Valewalker Arboreal Fire overwrites stronger damage add
The damage add for the valewalker Arboreal Fire style is 4.5 points for 30 seconds, not horrible but significantly less useful than the 10 minute damage add for more than twice that damage which is available from several classes. This wouldn't be a problem if they stacked (best case since 4.5 points isn't overpowering even at relatively low level and it's a reactive style so it can't be maintained at will) or if the more powerful damage add prevailed, but as it is a 30 second moderate damage add cancels out whatever remains of a stronger damage add which means having to recast the stronger buff every time you use the style.
If making the buffs "play nicely" isn't practical, then another option would be upping the style's damage add to the point that it is worth the inconvenience of having to rebuff. Mauler's Jolting staff for instance gives a 50 point buff for 60 seconds. Granted it is a level 15 style vs. level 8, but it is available substantially at will since its style chain isn't reactive based. It should be said that Jolting Staff does also overwrite other buffs, but for 50 points of damage add that's relatively easy to reapply it's hard to complain.
If making the buffs "play nicely" isn't practical, then another option would be upping the style's damage add to the point that it is worth the inconvenience of having to rebuff. Mauler's Jolting staff for instance gives a 50 point buff for 60 seconds. Granted it is a level 15 style vs. level 8, but it is available substantially at will since its style chain isn't reactive based. It should be said that Jolting Staff does also overwrite other buffs, but for 50 points of damage add that's relatively easy to reapply it's hard to complain.