Recursion PHP function returns 500 error - php

Question

Hi I'm have recursion function that makes binary tree array, so from that
array(
array(
'name' => 'John',
'id' => 1,
'mother_id' => 2,
'father_id' => 3
),
array(
'name' => 'Lucy',
'id' => 2,
'mother_id' => 5,
'father_id' => 4
),
array(
'name' => 'Jim',
'id' => 3,
'mother_id' => 7,
'father_id' => 9
),
array(
'name' => 'Paul',
'id' => 4,
'mother_id' => 534,
'father_id' => 54
),
array(
'name' => 'Laura',
'id' => 5,
'mother_id' => 554,
'father_id' => 51
),
array(
'name' => 'Vanessa',
'id' => 7,
'mother_id' => 5354,
'father_id' => 514
),
array(
'name' => 'Adam',
'id' => 9,
'mother_id' => 245354,
'father_id' => 514234
),
);
I'm getting that:
array(
array(
'person' => array(
'name' => 'John',
'id' => 1,
'mother_id' => 2,
'father_id' => 3
),
'parents' => array(
'mother' => array(
'person' => array(
'name' => 'Lucy',
'id' => 2,
'mother_id' => 5,
'father_id' => 4
),
'parents' => array(
'mother' => array(
'person' => array(
'name' => 'Laura',
'id' => 5,
'mother_id' => 554,
'father_id' => 51
),
'parents' => array(...)
),
'father' => array(
'person' => array(
'name' => 'Paul',
'id' => 4,
'mother_id' => 534,
'father_id' => 54
),
'parents' => array(...)
),
)
),
'father' => ...
)
and it works completely fine until it gets array with more than -+100 values, and when it gets this array, it returns 500 error, that's seems strange for me, cos obviously I don't have infinite loop or something like that, cos smallest arrays parses fine but I can't figure out what's reason for this kind of behavior.
function parseTree(&$tree, $root = null)
{
$return = null;
foreach ($tree as $key => $item) {
if ($root == null || $item['id'] == $root) {
$return = [
'person' => $item,
'parents' => [
'father' => parseTree($tree, $item['father_id']),
'mother' => parseTree($tree, $item['mother_id'])
]
];
unset ($tree[$key]);
}
}
return $return;
}