that is very easy.. and here is how...
Open your Dragon folder to.. \...\Dragon\Scripts\items
In there you will see a variety of files for all the static items that Dragon places from your color table groups.
In the Forest.txt when open you will see somthing similar to this..
Code:
// -------------------------------------------------------------------
// Syntax :
// [Frequency] [ItemGroup1] [ItemGroup2] [ItemGroup3] ...
//
// Itemgroup = [Item(hex)] [ZLevel(dec)] [Color(hex)] [Xmovement(dec)] [Ymovement(dec)]
// -------------------------------------------------------------------
//Tree (Grey) + green leaves
0005 0ccd 0000 0000 0000 0000 0cce 0000 0000 0000 0000
//Tree (Grey) + red leaves
//0002 0ccd 0000 0000 0000 0000 0ccf 0000 0000 0000 0000
//Tree (warm brown) + green leaves
0005 0cd0 0000 0000 0000 0000 0cd1 0000 0000 0000 0000
//Tree (warm brown) + red leaves
//0001 0cd0 0000 0000 0000 0000 0cd2 0000 0000 0000 0000
Notice the lines that start with the double frontslash (comment marks).
Those will not get placed by Dragon. If you remove the // It will place them.
tree (warm brown) + red leaves = a fall tree, wich I have 'commented' out
just go through and edit to your prefrences. add in other items if you want too
*edited text to fit the code box*