I had trouble with flickering trees so I changed thie entry in Vogesen_data
and now everything is perfect
[AlphaObjectTextureMaterial]
DepthBufferCheck=TRUE
DepthBufferWrite=FALSE
RenderedInOrder=false
AlphaTestEnabled=TRUE
CullMode=NO_CULL
LightEnabled=TRUE
SpecularEnabled=FALSE
EmissiveEnabled=FALSE
FogEnabled=TRUE
AmbientColor=1.000000,1.000000,1.000000,1.00000
DiffuseColor=1.000000,1.000000,1.000000,1.00000
ZBufferOffset=2.000000
BlendOp=BLEND_SRC_ALPHA
NumTextureStages=1
TextureStage[01].TextureName=
TextureStage[01].MipMap=TRUE -----CHANGE THIS LINE TO TRUE
TextureStage[01].FilterEnabled=TRUE
TextureStage[01].StageColorOp=TEXTURE_MODULATE_DIFFUSE
TextureStage[01].StageAlphaOp=TEXTURE
Fade=NORMAL
StartFadeDistance=50.0
EndFadeDistance=50.0