NOTE: Follow this ONLY if you don't like the branches and/or groundcover/grass, but want to keep the bark and shrubs.

Some comparisons (watch them sliding and in full resolution):

SFO FULL:
http://imageshack.us/f/607/tesv2011121721013041.jpg

SFO only bark, shrubs and part of branches:
http://imageshack.us/f/9/vurtsemi.jpg

This works for v1.0.7 of the mod.

-Install "Skyrim Skyrim Flora Overhaul" then also install "Gloomy Snowy Pines" addon. Don't install "Thinner Grass", since we're going to remove the grass.

REMOVING (partially) BRANCHES:

From your Skyrim Data/textures/architecture/whiterun folder:
-REMOVE:
wrtreefloweringbranch01.dds
wrtreefloweringbranch01_N.dds

From your Skyrim Data/textures/landscape/trees folder:
-REMOVE:
reachtreebranch01.dds
reachtreebranch01_N.dds
treeaspenbranchcomp.dds
treeaspenbranchcomp_n.dds
treepineforestbranchcomp.dds
treepineforestbranchcomp_n.dds
treepineforestbranchcompsnow.dds
treepineforestbranchcompsnow_n.dds
treepineforestbranchcompsnowl.dds
treepineforestbranchcompsnowl_n.dds

REMOVING GROUNDCOVER/GRASS

From your Skyrim Data/textures/landscape folder:
-REMOVE the "grass" folder.

PS: Every time you'll update the mod via NMM, you'll need to re-do this procedure!