It is the Fortree Gym. Hope it helps!
It is Wynona, she is a gym leader who use's flying type pokemon.
Janine I think
Pokemon leader wionda - bird and flying type Pokemon.
The six gym leader location in Pokemon Heart Gold is Olivine City, but you battle the one in Cinnabar first.
it is in the south of Fuchsia City. the gym leader is Koga.
The 6 gym leader in at Canalave City. the gym after the hearthome City gym!!!!!
The six gym is told to you by your bro Kevin and if you still don't know you go to the steel gym then go down then you see the spot with eater you surf right and your at the 6 gum town.
the sixth gym leader is bryon-the gym in canalave city . you can also go to the website to check the gym leaders(http://www.serebii.net/diamondpearl/gymleaders.shtml)
Fuchshia City
blackthorn
go past the tree city and then past the big patch of grass and then you'll see a bridge with steven on it go talk to him and he gives you a scope so you can see the Pokemon blocking the way
You have to have a ds lite, if you do go down until you see migrate from ruby and then pick the six Pokemon you want.