You'll get a warning later if you try to use it.
Not necessarily: 
#line 1
use strict;
use warnings;
our $tree;

$tree = {};
$$tree{autov} = "ivify";
warn %$tree;
# vs.
$tree = undef;
$$tree{autov} = "ivify";
warn %$tree;

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In reply to Re: Re: Deallocating HASH pointer by ysth
in thread Deallocating HASH pointer by Anonymous Monk

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