diff --git a/src/pocketmine/level/generator/object/Ore.php b/src/pocketmine/level/generator/object/Ore.php
index 5ca1ffa61..14ab43045 100644
--- a/src/pocketmine/level/generator/object/Ore.php
+++ b/src/pocketmine/level/generator/object/Ore.php
@@ -84,7 +84,7 @@ class Ore{
 								$sizeZ = ($z + 0.5 - $seedZ) / $size;
 								$sizeZ *= $sizeZ;
 
-								if(($sizeX + $sizeY + $sizeZ) < 1 and $level->getBlockIdAt($x, $y, $z) === 1){
+								if(($sizeX + $sizeY + $sizeZ) < 1 and $level->getBlockIdAt($x, $y, $z) === Block::STONE){
 									$level->setBlockIdAt($x, $y, $z, $this->type->material->getId());
 									if($this->type->material->getDamage() !== 0){
 										$level->setBlockDataAt($x, $y, $z, $this->type->material->getDamage());
diff --git a/src/pocketmine/level/generator/populator/Tree.php b/src/pocketmine/level/generator/populator/Tree.php
index 02c41d93d..85bb071eb 100644
--- a/src/pocketmine/level/generator/populator/Tree.php
+++ b/src/pocketmine/level/generator/populator/Tree.php
@@ -68,7 +68,7 @@ class Tree extends Populator{
 			$b = $this->level->getBlockIdAt($x, $y, $z);
 			if($b === Block::DIRT or $b === Block::GRASS){
 				break;
-			}elseif($b !== 0 and $b !== Block::SNOW_LAYER){
+			}elseif($b !== Block::AIR and $b !== Block::SNOW_LAYER){
 				return -1;
 			}
 		}