[Vpmedia]

They can added using map_T.tga

Adjust the 'Levels' so Photoshop, that the woods become visible.

You can clone the wood pixels by selecting them with the marque tool (select only 1 pixel) then switch to the move tool and drag the pixel while pressing Alt at the same time.

Different colors represent different texture areas ->

BY LOWFIGHTER:

Map_T.tga is divided into regions of different colors.
The regions have corresponding names in the load.ini of that map.
For example land regions are called in the load.ini:
lowland0, lowland1..., midland0,midland1,.., mount0,mount1,...,country0,..., city0, Airfield0,...
A region (lowland3 for example) will always have exactly the same color an ALL maps.
Color code on the map_T
R=G=B=
0-3 lowland0 to lowland3
4-7 midland0 to ...
8-11 mount
12-15 country
16-19 city
20-23 airfield
24-27 wood
28-31 water

In the load.ini to different regions are asigned different textures, for example
LowLand0 = land/summer/mount.tga
That means that all lowland0 region as defined in map_T.tga will be filled with the texture mount.tga present in the /land/summer/ directory
So swapping textures means changing the texture names in assignements like the one above.
Normaly country and city regions will have village, town and industrial textures

*edit: imho the texture modification possibilities are unlimited