Obviously, this isn't a game screenshot, just a chart showing the structure of a hypothetical skill tree. The orange skills are stat-boosting passives. Blue skills are MP abilities, green skills are TP abilities, and purple skills are trait-bestowing passive skills. Each skill has a maximum level which it may be upgraded to (at left), and perquisites (noted by arrows and the smaller text in the boxes). The yellow circles show what level a skill needs to be to unlock the next.
One flaw with this particular example is that all of the incremental skill levels creates a lot of skills! Sure, most of these can be copied and pasted with small modifications, and the database limit is pretty large. Hence my question about having fewer but costlier to acquire skills. It simplifies things immensely for the developer - but there's more of a risk of players pouring lots of skill points into a skill that they may not like later.