CatServer/patches/net/minecraft/world/gen/feature/WorldGenBirchTree.java.patch

--- ../src-base/minecraft/net/minecraft/world/gen/feature/WorldGenBirchTree.java
+++ ../src-work/minecraft/net/minecraft/world/gen/feature/WorldGenBirchTree.java
@@ -56,9 +56,9 @@
                 {
                     for (int i1 = position.getZ() - k; i1 <= position.getZ() + k && flag; ++i1)
                     {
-                        if (j >= 0 && j < 256)
+                        if (j >= 0 && j < worldIn.getHeight())
                         {
-                            if (!this.canGrowInto(worldIn.getBlockState(blockpos$mutableblockpos.setPos(l, j, i1)).getBlock()))
+                            if (!this.isReplaceable(worldIn, blockpos$mutableblockpos.setPos(l, j, i1)))
                             {
                                 flag = false;
                             }
@@ -77,11 +77,13 @@
             }
             else
             {
-                Block block = worldIn.getBlockState(position.down()).getBlock();
+                BlockPos down = position.down();
+                IBlockState state = worldIn.getBlockState(down);
+                boolean isSoil = state.getBlock().canSustainPlant(state, worldIn, down, net.minecraft.util.EnumFacing.UP, (net.minecraft.block.BlockSapling)Blocks.SAPLING);
 
-                if ((block == Blocks.GRASS || block == Blocks.DIRT || block == Blocks.FARMLAND) && position.getY() < 256 - i - 1)
+                if (isSoil && position.getY() < worldIn.getHeight() - i - 1)
                 {
-                    this.setDirtAt(worldIn, position.down());
+                    state.getBlock().onPlantGrow(state, worldIn, down, position);
 
                     for (int i2 = position.getY() - 3 + i; i2 <= position.getY() + i; ++i2)
                     {
@@ -99,9 +101,9 @@
                                 if (Math.abs(j1) != l2 || Math.abs(l1) != l2 || rand.nextInt(2) != 0 && k2 != 0)
                                 {
                                     BlockPos blockpos = new BlockPos(i3, i2, k1);
-                                    Material material = worldIn.getBlockState(blockpos).getMaterial();
+                                    IBlockState state2 = worldIn.getBlockState(blockpos);
 
-                                    if (material == Material.AIR || material == Material.LEAVES)
+                                    if (state2.getBlock().isAir(state2, worldIn, blockpos) || state2.getBlock().isAir(state2, worldIn, blockpos))
                                     {
                                         this.setBlockAndNotifyAdequately(worldIn, blockpos, LEAF);
                                     }
@@ -112,9 +114,10 @@
 
                     for (int j2 = 0; j2 < i; ++j2)
                     {
-                        Material material1 = worldIn.getBlockState(position.up(j2)).getMaterial();
+                        BlockPos upN = position.up(j2);
+                        IBlockState state2 = worldIn.getBlockState(upN);
 
-                        if (material1 == Material.AIR || material1 == Material.LEAVES)
+                        if (state2.getBlock().isAir(state2, worldIn, upN) || state2.getBlock().isLeaves(state2, worldIn, upN))
                         {
                             this.setBlockAndNotifyAdequately(worldIn, position.up(j2), LOG);
                         }