well it's a problem if you don't know where to look.
first those tree's you're talking about are "nest towers" or "nest dais" what they do is respawning the flying enemy's you encounter as a dragon.
the red shield is an anti dragon zone with means if you fly through the shield as a dragon YOU DIE!
how to deactivate them:
look at the map. there you see two channels. in the middle between the two channels, is a small piece of land you can go to.
on this piece of land there is a teleporter named: "camp sentinal view". go through it
save your game NOW, because you have to fight two black ring (a couple).
go up the ladder and defeat them. then go upstairs you see three levers flip them to remove the anti dragon shield
well enjoy scouting the orobas fjords;)
