I'm trying to understand the logic of a spirit, a wooden spirit, a wooden spirit in no way related to any kind of mammal, having boobs. What in-universe reason is there? Your guess is as good as mine.
The dryad itself is interesting. Fey RHD are not very good: they're basically bard HD with worse weapon proficiencies, no armor profiencies, and low-light vision. I guess one might make use of the fey-ness and longbow proficiency with Charming the Arrow, but that's all I can think of.
Ability boosts are great. Huge dexterity bonus, huge charisma bonus, smaller boosts to wisdom and intelligence. DR/cold iron goes a long way towards increasing survivability at lower levels, as does the natural armor. Wild Empathy may help out against low-level animal encounters, especially with the huge charisma and racial bonuses dryads have.
A minor problem is Tree Dependency: adventuring is hard if you can't survive more than a day away from your home tree. Fortunately there's a large number of ways around this: Acorn of Far Travel is straightforward, Ability Rip (or even Shapechange) works at higher levels, and even Antimagic Shackles would technically help here.
Finally, there's the SLA's, without a doubt the best part of being a dryad. The at-wills fall in the same pattern of a situational but powerful-if-used-right ability with a plant theme, the 3/days respectively mean 'win social encounter', 'trivialize combat encounter' and 'travel ridiculously fast'. Suggestion is rather lackluster compared to all that, but still usable.
So what LA to give here? A dryad gets some very powerful SLA's, and a LA of +1* seems the absolute minimum to give because of them (the asterisk assumes Tree Dependency is removed). Then again, the other parts of the monster aren't that great, and at higher levels it's hard for the original abilities to remain relevant. +1* seems fine to me.