--- ../src_base/common/net/minecraft/src/WorldGenShrub.java
+++ ../src_work/common/net/minecraft/src/WorldGenShrub.java
@@ -17,10 +17,16 @@
     {
         int var15;
 
-        for (boolean var6 = false; ((var15 = par1World.getBlockId(par3, par4, par5)) == 0 || var15 == Block.leaves.blockID) && par4 > 0; --par4)
+        Block block = null;
+        do 
         {
-            ;
-        }
+            block = Block.blocksList[par1World.getBlockId(par3,  par4, par5)];
+            if (block != null && !block.isLeaves(par1World, par3, par4, par5))
+            {
+                break;
+            }
+            par4--;
+        } while (par4 > 0);
 
         int var7 = par1World.getBlockId(par3, par4, par5);
 
@@ -42,7 +48,10 @@
                     {
                         int var14 = var13 - par5;
 
-                        if ((Math.abs(var12) != var10 || Math.abs(var14) != var10 || par2Random.nextInt(2) != 0) && !Block.opaqueCubeLookup[par1World.getBlockId(var11, var8, var13)])
+                        block = Block.blocksList[par1World.getBlockId(var11, var8, var13)];
+
+                        if ((Math.abs(var12) != var10 || Math.abs(var14) != var10 || par2Random.nextInt(2) != 0) && 
+                            (block == null || block.canBeReplacedByLeaves(par1World, var11, var8, var13)))
                         {
                             this.setBlockAndMetadata(par1World, var11, var8, var13, Block.leaves.blockID, this.field_76527_a);
                         }