Hey man, i wanted to say that i definitely appreciate your struggle and i like some of the elements that you have going on here. the trunk of the tree in your first image next to the 'flat tree' text i think shows the most promise in trunk design, i was hoping to see you use that one for the basis of your experiments.
I wanted to run through with this with you , so i actually decided to download one of the video capture programs in the off topic forum thread and give it a go from scratch. unfortunately just like every other program that i tried using yesterday, it crashed at the very end after i stopped recording, so that just added some whipped cream on top of my cursed luck sundae for the day.
so ill post the image in a very early stage, toock me about 15 minutes to get to this point.

i dont think that this alone is going to say much for the process that i was using to get here (and yeah i realize it still looks really rough and the branches/leaves needs more balancing), so when i have a few minutes at work, ill make a simple animation of what each layer might look like and the order i drew it to get to where i am here. not nearly as good as a recording but itll have to do. Just to try to briefly explain into words, i do like your practice of forming out the skeleton of the tree with the branches, no detail is required there as youve been just scribbling them in just fine, so long as you get a nice balanced skeleton of the leafwork required in the tree you should be alright. From there, made a layer behind the tree branches, used a really dark, desaturated greenish blue and paint in large globs of leaf clusters. this stage forms the general shape and balance of the bulk of the greenery. The only thing on this layer im worried about is shape and balance, no leaf detail goes here. Then i made a new layer that goes over top of that one and the tree branch layer to start filling in the details of the highlights.
perhaps tonight ill try a different piece of software and try recording the next phase in detailing even though i dont think that stage is as critical to watch via video.
*edit* wtf is going on with the img encoding? will fix that at work. have to run!