Steam->SteamApps->common->DayZ->Addons
"and remove all the big (the ones with like 270kb) plants2_ files (plants2_plant, plants2_tree etc.) you can also remove the rocks3.pbo files to remove rocks and structure_ for buidlings.I didnt really test it I only know you can join a server without getting kicked so yea. In the mod you could shoot through the trees etc."