Is the only way to get high q branches planting a tree?

[babyhero09]

Can you find high quality ones just on wild trees?

[SacreDoom]

No. You simply cannot.

[Garath]

second that. wild tree branches cap at 10, as do their logs (soft cap) and blocks

[Riou1231]

Or you can trade with somebody, although I doubt anybody would be selling branches, most or even all would be selling the specific seeds for that tree. If you do consider buying one, make sure you have a decent farming level, full nature, and a good herb table and planter's pot before trying to make a sapling out of it.