[Solved] call to function on null error

I keep receiving this error when I run my plugin to generate a new world.

Code:

 [Asynchronous Worker #1 thread/CRITICAL]: Error: "Call to a member function getLevel() on null" (EXCEPTION) in "/src/pocketmine/tile/Tile" at line 124

I know that the chunk doesn't return a null because the tree is properly generated, but it still gives that error output. Anyone know what could be causing this? I am using the mcpe-1.0 branch for the server.

PHP:

$chunk = $this->level->getChunk($chunkX, $chunkZ);
Tree::growTree($this->level, $chunkX * 7 + 3, 64, $chunkZ * 7 + 3, $this->random, Sapling::OAK);
$chunk->setBlock($chunkX * 7 + 2, 64, $chunkZ * 7 + 3, Block::CHEST, 0);
$nbt = new CompoundTag("", [
    new ListTag("Items", [
        Item::get(Item::ICE,0,2),
        Item::get(Item::MELON),
        Item::get(Item::TORCH,0,2),
        Item::get(Item::BONE),
        Item::get(Item::BUCKET,1),
        Item::get(Item::PUMPKIN_SEEDS),
        Item::get(Item::SUGAR_CANE),
        Item::get(Item::RED_MUSHROOM),
        Item::get(Item::BROWN_MUSHROOM),
        Item::get(Item::CACTUS),
        Item::get(Item::BREAD),
        Item::get(Item::WHEAT),
        Item::get(Item::LEATHER_BOOTS),
        Item::get(Item::LEATHER_CAP),
        Item::get(Item::LEATHER_TUNIC),
        Item::get(Item::LEATHER_PANTS)
    ]),
    new IntTag("x", $chunkX * 7 + 2),
    new IntTag("y", 64),
    new IntTag("z", $chunkX * 7 + 3),
]);
$tile = new Chest($chunk, $nbt);
$chunk->addTile($tile);