I'm looking to take an image looking out at a storm in the distance that has a fairly uneven horizon due to trees and a foreground fence post and only increase the contrast and decrease the brightness on the sky portion.
The lighting in the image is such that the foreground grass/fence becomes far too dark when I increase contrast and decrease brightness, but it makes the sky look absolutely fantastic. I've tried to use the magic wand and intelligent scissors in Gimp to try and outline the horizon and each and every time even the slightest mistake like missing some sky or including some tree in the selection is very obvious once the adjustments are made (avoiding that seems almost impossible). If no better solution exists I suppose a tedious hand draw is possible, I'm just curious about alternatives.
Is there an effective way to split the image across the horizon so I can only modify the sky portion in Gimp and leave the ground unchanged?