diff --git a/Effects/cropgrass.eff b/Effects/cropgrass.eff
index 72d1b554c..ee78881ce 100644
--- a/Effects/cropgrass.eff
+++ b/Effects/cropgrass.eff
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <PropertyList>
   <name>Effects/cropgrass</name>
-  <inherits-from>Effects/terrain-default</inherits-from>
+  <inherits-from>Effects/crop</inherits-from>
   <parameters>
     <texture n="2">
         <image>Textures/Terrain/cropgrass.png</image>
@@ -18,92 +18,4 @@
     </texture>
     <snow-level><use>/sim/rendering/snow-level-m</use></snow-level>
   </parameters>
-  <technique n="9">
-    <predicate>
-      <and>
-        <property>/sim/rendering/crop-shader</property>
-        <property>/sim/rendering/shader-effects</property>
-        <or>
-          <less-equal>
-            <value type="float">2.0</value>
-            <glversion/>
-          </less-equal>
-          <and>
-            <extension-supported>GL_ARB_shader_objects</extension-supported>
-            <extension-supported>GL_ARB_shading_language_100</extension-supported>
-            <extension-supported>GL_ARB_vertex_shader</extension-supported>
-            <extension-supported>GL_ARB_fragment_shader</extension-supported>
-          </and>
-        </or>
-      </and>
-    </predicate>
-    <pass>
-      <lighting>true</lighting>
-      <!-- Use material values that are either inherited from the
-           terrain-default effect or supplied by an effect derived
-           from this one e.g., one created in the materials library. -->
-      <material>
-        <ambient><use>material/ambient</use></ambient>
-        <diffuse><use>material/diffuse</use></diffuse>
-        <specular><use>material/specular</use></specular>
-        <color-mode>ambient-and-diffuse</color-mode>
-      </material>
-      <blend><use>transparent</use></blend>
-      <alpha-test><use>transparent</use></alpha-test>
-      <shade-model>smooth</shade-model>
-      <cull-face>back</cull-face>
-      <render-bin>
-        <bin-number><use>render-bin/bin-number</use></bin-number>
-        <bin-name><use>render-bin/bin-name</use></bin-name>
-      </render-bin>
-      <texture-unit>
-        <unit>0</unit>
-        <type>noise</type>
-      </texture-unit>
-      <texture-unit>
-        <unit>1</unit>
-          <image><use>texture[2]/image</use></image>
-          <filter><use>texture[2]/filter</use></filter>
-          <wrap-s><use>texture[2]/wrap-s</use></wrap-s>
-          <wrap-t><use>texture[2]/wrap-t</use></wrap-t>
-          <internal-format>
-            <use>texture[2]/internal-format</use>
-          </internal-format>
-      </texture-unit>
-      <texture-unit>
-        <unit>2</unit>
-          <type>1d</type>
-          <image><use>texture[3]/image</use></image>
-          <filter><use>texture[3]/filter</use></filter>
-          <wrap-s><use>texture[3]/wrap-s</use></wrap-s>
-          <internal-format>
-            <use>texture[3]/internal-format</use>
-          </internal-format>
-      </texture-unit>
-      <program>
-        <vertex-shader>Shaders/crop.vert</vertex-shader>
-        <fragment-shader>Shaders/crop.frag</fragment-shader>
-      </program>
-      <uniform>
-        <name>NoiseTex</name>
-        <type>sampler-3d</type>
-        <value type="int">0</value>
-      </uniform>
-      <uniform>
-        <name>SampleTex</name>
-        <type>sampler-2d</type>
-        <value type="int">1</value>
-      </uniform>
-      <uniform>
-        <name>ColorsTex</name>
-        <type>sampler-1d</type>
-        <value type="int">2</value>
-      </uniform>
-      <uniform>
-        <name>snowlevel</name>
-        <type>float</type>
-        <value><use>snow-level</use></value>
-      </uniform>
-    </pass>
-  </technique>
 </PropertyList>
diff --git a/Effects/forest.eff b/Effects/forest.eff
index e189b587a..438d30dfa 100644
--- a/Effects/forest.eff
+++ b/Effects/forest.eff
@@ -49,7 +49,7 @@
   <technique n="9">
     <predicate>
       <and>
-        <property>/sim/rendering/crop-shader</property>
+        <property>/sim/rendering/transition-shader</property>
         <property>/sim/rendering/shader-effects</property>
         <or>
           <less-equal>
diff --git a/Effects/glacier.eff b/Effects/glacier.eff
index da9a06146..c5fb1f2db 100644
--- a/Effects/glacier.eff
+++ b/Effects/glacier.eff
@@ -49,7 +49,7 @@
   <technique n="9">
     <predicate>
       <and>
-        <property>/sim/rendering/crop-shader</property>
+        <property>/sim/rendering/transition-shader</property>
         <property>/sim/rendering/shader-effects</property>
         <or>
           <less-equal>
diff --git a/Effects/herbtundra.eff b/Effects/herbtundra.eff
index 5f97c2112..6b819d16e 100644
--- a/Effects/herbtundra.eff
+++ b/Effects/herbtundra.eff
@@ -49,7 +49,7 @@
   <technique n="9">
     <predicate>
       <and>
-        <property>/sim/rendering/crop-shader</property>
+        <property>/sim/rendering/transition-shader</property>
         <property>/sim/rendering/shader-effects</property>
         <or>
           <less-equal>
diff --git a/Shaders/forest.frag b/Shaders/forest.frag
index 4641a8000..b0b08697f 100644
--- a/Shaders/forest.frag
+++ b/Shaders/forest.frag
@@ -7,6 +7,7 @@ varying vec3 VBinormal;
 varying vec3 VNormal;
 varying vec3 Normal;
 varying float bump;
+varying float fogCoord;
 
 uniform sampler3D NoiseTex;
 uniform sampler2D SampleTex;
@@ -98,13 +99,11 @@ void main (void)
 	
 	float vegetationlevel = (rawpos.z)+nvL[2]*3000.0;
 
-	float fogFactor;
-	float fogCoord = ecPosition.z;
 	const float LOG2 = 1.442695;
-	fogFactor = exp2(-gl_Fog.density * gl_Fog.density * fogCoord * fogCoord * LOG2);
+	float fogFactor = exp(-gl_Fog.density * gl_Fog.density * fogCoord * fogCoord);
 	float biasFactor = exp2(-0.00000002 * fogCoord * fogCoord * LOG2);
 
-	float n=0.06;
+	float n = 0.06;
 	n += nvL[0]*0.4;
 	n += nvL[1]*0.6;
 	n += nvL[2]*2.0;
@@ -114,7 +113,9 @@ void main (void)
 
 	n += noisevec[2]*0.8;
 	n += noisevec[3]*2.1;
-	n = mix(0.6, n, biasFactor);
+	
+	//very low n/biasFactor mix, to keep forest color
+	n = mix(0.05, n, biasFactor);
 	
 	vec4 c1;
 	c1 = basecolor * vec4(smoothstep(-1.3, 0.5, n), smoothstep(-1.3, 0.5, n), smoothstep(-2.0, 0.9, n), 0.0);
diff --git a/Shaders/forest.vert b/Shaders/forest.vert
index de27c5ac3..8cf6cbb7e 100644
--- a/Shaders/forest.vert
+++ b/Shaders/forest.vert
@@ -6,6 +6,7 @@ varying vec3  VBinormal;
 varying vec3  Normal;
 varying vec4  constantColor;
 varying float bump;
+varying float fogCoord;
 
 attribute vec3 tangent;
 attribute vec3 binormal;
@@ -25,4 +26,7 @@ void main(void)
 		+ gl_FrontColor * (gl_LightModel.ambient + gl_LightSource[0].ambient);  
 	gl_Position = ftransform();
 	gl_TexCoord[0] = gl_TextureMatrix[0] * gl_MultiTexCoord0;
+	
+    fogCoord = abs(ecPosition.z / ecPosition.w);
+	
 }
diff --git a/gui/dialogs/rendering.xml b/gui/dialogs/rendering.xml
index 114f1f0ca..29e42dbc8 100644
--- a/gui/dialogs/rendering.xml
+++ b/gui/dialogs/rendering.xml
@@ -270,6 +270,15 @@
             <command>dialog-apply</command>
           </binding>
         </checkbox>
+        
+        <checkbox>
+          <halign>left</halign>
+          <label>Transition effects</label>
+          <property>/sim/rendering/transition-shader</property>
+          <binding>
+            <command>dialog-apply</command>
+          </binding>
+        </checkbox>
 
         <checkbox>
           <halign>left</halign>
diff --git a/preferences.xml b/preferences.xml
index c3f8c3327..8cd338604 100644
--- a/preferences.xml
+++ b/preferences.xml
@@ -596,6 +596,7 @@ Started September 2000 by David Megginson, david@megginson.com
 
   <traffic-manager>
      <enabled type="bool">true</enabled>
+     <heuristics type="bool">true</heuristics>
      <instantaneous-action type="bool">false</instantaneous-action>
      <proportion>1.0</proportion>
   </traffic-manager>