Just a few suggestions for those who may wish to draw on wood using TMP. Of course, I have been using this mainly for art over the past week, but there are many other applications, especially in cities where you want the save to have more depth, without using deco. Darkened wood often implies aged and weathered structures, or fire damage.

I recommend building or drawing all of the contours or structures first, so that you don't need to keep switching between the PROP tool and elements. 

If you want all the WOOD to have the same base color before you start adding the details, open the console with ` (the ~ key), and use

!set tmp wood ### 

I've used this when I have cities that are built using wood strcutures. This way I don't have to make the pen humongous, and it ensures I don't miss any particles. 

Then is the annoying part. Click the PROP tool, and select TMP. You then enter the number for the TMP, and draw with it. 

WOOD begins to change color above TMP 400. My scale for shading is usually from 400 to 1000 at intervals of 50. To create more "delicate" shading you can go on even smaller intervals, but you need more space to do that. 

To shade WOOD in art applications, you usually have fairly thick sections, unlike cities where the total thickness can be as low as 1 pixel for a floor, so I use the following method: Begin with your lowest TMP value (brightest shade), and shade in the entire shaded area. Each time you bump up the TMP value, you shade in a little less of the total shaded area, layering the new TMP value over the old one. With enough practice, you can shade a large section fairly quickly, to a high level of detail. If you start with the darkest shade, you have to zoom in and be careful not to overwrite the previous layer, which is time consuming and annoying. 

City example, completed:

Art example, in the middle of shading: