This is from my Stillman & Birn soft cover (blue) sketchbook with 180# paper. A part of me likes the thing, and another doesn’t. I’m not sure why.
Anyway, this shows what I am trying to do . . . establish shadow, play with color combos or swatches. I used all sorts of brushes on this. In general, it is overworked, and the trunk looks like some tree has landed on an octopus. (Poor octopus!)
This is the final product, with some work on it . . . The contrast is a bit better, but it still looks pretty much in the same key to me – in other words, the grey scale is pretty much the same to my eye when I see it in color. In B&W it is still not quite what I would like to see.