class node {
	public $age = 10;
	
	public function __construct(/*int*/ $age){
		$this->age = $this->age + $age;
	}
	
	public function getAge(){
		return $this->age;
	} 
}

class tree {
	
	public static function getNodes(/*int*/ $number){
		$nodes = array();
		for($i=0; $i<=$number; $i++){
			$nodes[] = new node($i);
		}
		return $nodes;
	}
}

$Tree = tree::getNodes(9);
foreach($Tree as $Node){
	echo 'Node age:'.$Node->getAge();
}	

$Tree = tree::getNodes(9);
foreach($Tree as $Node){
	/* @var $Node node */
	echo 'Node age:'.$Node->getAge();
}

class tree{
  public /* @return array node */ function getNodes(){
  ... return array... 
  }
}