Add green color on trees

[Ofnuts]

Two fundamentals problems with the image:

• Color temperature isn't quite right
  
• Not many values to work with in these trees, so any  change there will create blobs
  

My processing:

• Convert image to high-precision
  
• Add a very low HSV noise (just enough V to make the histogram continuous) to avoid being hit by quantization problems
  
• Colors > Color temperature to improve the color temperature (eyeballed it...)
  
• Create a luminosity mask that covers the tree and the lawns (pretty much a dark/midtones one, with the water painted over at the bottom)
  

   

• Using the mask a a selection, add a slight boost to the Green channel in Curves