I ended up installing 2 more mods arthmoor's darkwater crossings and whistling mine and decided to re-generate lods and esp by clean saving. but i will remember this procedure next time if i don't change mods in between. Thanks sheson.
I was previously using 3d lods for trees and now want to switch back to 2d lods coz in some places it is very taxing can i just re-generate lod's again and activate it without following update procedure i.e without switching it off in MCM and saving and all that ?? or that update procedure is to be followed everytime ? i haven't changed anything in my game in relation to mods