Hey HotShot
Forrest are located in either data3d or 0.pbo depending on you wanna use res version or old OFP version.
Example....
In data3d.pbo there are various versions of trees and forrest, here is 1= (les ctverec pruchozi_T1)
I recomend that you download the pdf manual from the OFPCookbook, this contains screenies and names of all objects in old version OFP.
For the RES version you can download the HTML file here on OFPEC in the Editors Depot.
Jones Out!