clone.diff

diff --git a/lib/Mojo/DOM.pm b/lib/Mojo/DOM.pm
index 2bda8b1..86ee7f1 100644
--- a/lib/Mojo/DOM.pm
+++ b/lib/Mojo/DOM.pm
@@ -15,6 +15,7 @@ use Mojo::DOM::CSS;
 use Mojo::DOM::HTML;
 use Mojo::Util 'squish';
 use Scalar::Util qw(blessed weaken);
+use Storable 'dclone';
 
 sub all_text { shift->_all_text(1, @_) }
 
@@ -280,7 +281,11 @@ sub _offset {
 
 sub _parent { $_[0]->tree->[$_[0]->type eq 'tag' ? 3 : 2] }
 
-sub _parse { Mojo::DOM::HTML->new(xml => shift->xml)->parse(shift)->tree }
+sub _parse {
+  my ($self, $html) = @_;
+  return dclone $html->tree if blessed $html && $html->isa('Mojo::DOM');
+  return Mojo::DOM::HTML->new(xml => $self->xml)->parse($html)->tree;
+}
 
 sub _replace {
   my ($self, $parent, $tree, $new) = @_;