diff --git a/gui/dialogs/location-in-air.xml b/gui/dialogs/location-in-air.xml
index 4e2fa953a..ce16f3fae 100644
--- a/gui/dialogs/location-in-air.xml
+++ b/gui/dialogs/location-in-air.xml
@@ -261,7 +261,7 @@
         <command>nasal</command>
         <script>
           setprop("/sim/presets/parkpos", "");
-            
+
           if (!mode.airport.getBoolValue()) {
             setprop("/sim/presets/airport-id", "");
             setprop("/sim/presets/runway", "");
diff --git a/materials.xml b/materials.xml
index e3f79bf99..828bc5cdf 100644
--- a/materials.xml
+++ b/materials.xml
@@ -1320,6 +1320,9 @@ Shared parameters for various materials.
     <heading-type>random</heading-type>
    </object>
   </object-group>
+  <!-- Disabled to avoid a tremendous osg performance penalty when
+       deleting scenery tiles, caused by tens of thousands of shared
+       horse/cow objects. Need a better implementation!
   <object-group>
    <range-m>1000</range-m>
    <object>
@@ -1332,7 +1335,7 @@ Shared parameters for various materials.
     <coverage-m2>300000</coverage-m2>
     <heading-type>random</heading-type>
    </object>
-  </object-group>
+  </object-group> -->
   <wood-coverage>1000000.0</wood-coverage>
   <wood-size>20000.0</wood-size>
   <tree-density>4000.0</tree-density>
@@ -1383,6 +1386,9 @@ Shared parameters for various materials.
     <heading-type>random</heading-type>
    </object>
   </object-group>
+  <!-- Disabled to avoid a tremendous osg performance penalty when
+       deleting scenery tiles, caused by tens of thousands of shared
+       horse/cow objects. Need a better implementation!
   <object-group>
    <range-m>1000</range-m>
    <object>
@@ -1395,7 +1401,7 @@ Shared parameters for various materials.
     <coverage-m2>300000</coverage-m2>
     <heading-type>random</heading-type>
    </object>
-  </object-group>
+  </object-group> -->
   <wood-coverage>500000.0</wood-coverage>
   <tree-texture>Textures/Trees/mixed-summer.png</tree-texture>
   <tree-varieties>8</tree-varieties>
@@ -1444,6 +1450,9 @@ Shared parameters for various materials.
     <heading-type>random</heading-type>
    </object>
   </object-group>
+  <!-- Disabled to avoid a tremendous osg performance penalty when
+       deleting scenery tiles, caused by tens of thousands of shared
+       horse/cow objects. Need a better implementation!
   <object-group>
    <range-m>1000</range-m>
    <object>
@@ -1456,7 +1465,7 @@ Shared parameters for various materials.
     <coverage-m2>300000</coverage-m2>
     <heading-type>random</heading-type>
    </object>
-  </object-group>
+  </object-group> -->
   <wood-coverage>500000.0</wood-coverage>
   <wood-size>20000.0</wood-size>
   <tree-density>5000.0</tree-density>
@@ -2140,6 +2149,9 @@ Shared parameters for various materials.
     <heading-type>random</heading-type>
    </object>
   </object-group>
+  <!-- Disabled to avoid a tremendous osg performance penalty when
+       deleting scenery tiles, caused by tens of thousands of shared
+       horse/cow objects. Need a better implementation!
   <object-group>
    <range-m>1000</range-m>
    <object>
@@ -2152,7 +2164,7 @@ Shared parameters for various materials.
     <coverage-m2>300000</coverage-m2>
     <heading-type>random</heading-type>
    </object>
-  </object-group>
+  </object-group> -->
   <wood-coverage>1000000.0</wood-coverage>
   <wood-size>20000.0</wood-size>
   <tree-density>4000.0</tree-density>
@@ -2202,6 +2214,9 @@ Shared parameters for various materials.
     <heading-type>random</heading-type>
    </object>
   </object-group>
+  <!-- Disabled to avoid a tremendous osg performance penalty when
+       deleting scenery tiles, caused by tens of thousands of shared
+       horse/cow objects. Need a better implementation!
   <object-group>
    <range-m>1000</range-m>
    <object>
@@ -2214,7 +2229,7 @@ Shared parameters for various materials.
     <coverage-m2>300000</coverage-m2>
     <heading-type>random</heading-type>
    </object>
-  </object-group>
+  </object-group> -->
   <wood-coverage>150000.0</wood-coverage>
   <wood-size>10000.0</wood-size>
   <tree-density>5000.0</tree-density>
@@ -2264,6 +2279,9 @@ Shared parameters for various materials.
     <heading-type>random</heading-type>
    </object>
   </object-group>
+  <!-- Disabled to avoid a tremendous osg performance penalty when
+       deleting scenery tiles, caused by tens of thousands of shared
+       horse/cow objects. Need a better implementation!
   <object-group>
    <range-m>1000</range-m>
    <object>
@@ -2276,7 +2294,7 @@ Shared parameters for various materials.
     <coverage-m2>300000</coverage-m2>
     <heading-type>random</heading-type>
    </object>
-  </object-group>
+  </object-group> -->
   <wood-coverage>150000.0</wood-coverage>
   <wood-size>10000.0</wood-size>
   <tree-density>5000.0</tree-density>