How to build equal ranges of a green or brown tone in a color palette from dark to bright with RGB for images with R?

does anyone know how I can search in many images for green tones and cluster them for a later characterisation of the images? The idea is to include all shades of green from the green palette and only leave out as few as possible, none would be great actually. I have thought of taking a photo with a lot of green tones, clustering it using R and then creating areas between the values of the cluster centres. However, since forming areas of RGB images is a three-dimensional space, I find it difficult to form areas that contain all the color tones in total, but only one color tone should occur in an area, so there are no overlaps. It is also difficult to find an image with all green shades for the clustering. Does anyone have a tip for me?

Thanks in advance!