Work in Progress: Treeman

In my last post I shared an image of Thrud battling the wereman and a WIP progress treeman. Well, today I though that I might quickly share my progress on the said treeman. Personally, I have grown to really love this model since I acquired it some months ago. I think its something about the determined expression on the figure's face that appeals to me and I would love to get a couple more of these models to create a small unit of treemen. The trouble is, this model is one of the most expensive I have ever bought myself at £20 and sadly they seemed to appear rather infrequently. The other treeman made famous by Citadel in the '80s, used later as Klinty in McDeath, seems to be more commonly available. 

This particular model was part of the 1985 Lord of the Rings range from when Citadel originally held the license. He was originally sculpted to represent Treebeard in that range but was later packaged as a general treeman monster. Later on, in 1988 the model was given a second lease of life in a number of conversions for Bloodbowl. 

Now I share this model as a Work-in-Progress - which isn't something I usually do. You see, my previous post on Thrud represents me painting well within my comfort-zone. Leather, flesh and steel (what does that say about me??) while the two tone combination of greenery and wood on this treeman are something I found very challenging to achieve. 

What do you guys think? I am almost certian I am going to repaint the green leaves on the front of the model as they look blobby and undefined to my eye but your suggestions would be a great help if you are willing to share them. 

Ultimately, what I would like to know is how do to you paint wood and how do you achieve that vibrant green associated with plant life in paint! Can anyone help?