This a tip for people who still have problems with falling leaves. I may have a fix, although it is not tested yet.
Supposedly the latest version of nrass tempest sets leaves to 100% decay at the start of spring and summer. This may remove those pesky leaves.
If not, PrinceRuben stated in another thread that you can use the nrass debuger (mixed with the nrass master controller) to get rid of leaves.
"to be rid of leaves proceed with the following
click nraas>Debug Enabler>Options:> DEBUG:Leaves> Remove Leave from Tile
and Watch the leaves vanish as soon as the clock is running"
you can get both of those mods here
http://nraas.wikispaces.com