diff --git a/lib/closure_tree/acts_as_tree.rb b/lib/closure_tree/acts_as_tree.rb
index 7fc0829c..585ab1af 100644
--- a/lib/closure_tree/acts_as_tree.rb
+++ b/lib/closure_tree/acts_as_tree.rb
@@ -29,7 +29,7 @@ def acts_as_tree(options = {})
       # Auto-inject the hierarchy table
       # See https://github.com/patshaughnessy/class_factory/blob/master/lib/class_factory/class_factory.rb
       class_attribute :hierarchy_class
-      self.hierarchy_class = Object.const_set hierarchy_class_name, Class.new(ActiveRecord::Base)
+      self.hierarchy_class = ct_class.parent.const_set short_hierarchy_class_name, Class.new(ActiveRecord::Base)
 
       self.hierarchy_class.class_eval <<-RUBY
         belongs_to :ancestor, :class_name => "#{ct_class.to_s}"
@@ -50,5 +50,6 @@ def ==(comparison_object)
         include ClosureTree::DeterministicNumericOrdering if order_is_numeric
       end
     end
+
   end
-end
\ No newline at end of file
+end
diff --git a/lib/closure_tree/columns.rb b/lib/closure_tree/columns.rb
index 4f24d366..b6af38fb 100644
--- a/lib/closure_tree/columns.rb
+++ b/lib/closure_tree/columns.rb
@@ -37,6 +37,19 @@ def hierarchy_class_name
       closure_tree_options[:hierarchy_class_name] || ct_class.to_s + "Hierarchy"
     end
 
+
+    #
+    # Returns the constant name of the hierarchy_class
+    #
+    # @return [String] the constant name
+    #
+    # @example
+    #   Namespace::Model.hierarchy_class_name # => "Namespace::ModelHierarchy"
+    #   Namespace::Model.short_hierarchy_class_name # => "ModelHierarchy"
+    def short_hierarchy_class_name
+      hierarchy_class_name.split('::').last
+    end
+
     def quoted_hierarchy_table_name
       connection.quote_table_name hierarchy_table_name
     end
diff --git a/spec/db/schema.rb b/spec/db/schema.rb
index c6b3edb1..b9e782d9 100644
--- a/spec/db/schema.rb
+++ b/spec/db/schema.rb
@@ -95,4 +95,15 @@ def force_add_index(table_name, columns, options = {})
     t.integer "descendant_id", :null => false
     t.integer "generations", :null => false
   end
+
+  create_table "namespace_types", :force => true do |t|
+    t.string "name"
+    t.integer "parent_id"
+  end
+
+  create_table "namespace_type_hierarchies", :id => false, :force => true do |t|
+    t.integer "ancestor_id", :null => false
+    t.integer "descendant_id", :null => false
+    t.integer "generations", :null => false
+  end
 end
diff --git a/spec/namespace_type_spec.rb b/spec/namespace_type_spec.rb
new file mode 100644
index 00000000..85edf7ac
--- /dev/null
+++ b/spec/namespace_type_spec.rb
@@ -0,0 +1,13 @@
+require 'spec_helper'
+
+describe Namespace::Type do
+
+  context "class injection" do
+    it "should build hierarchy classname correctly" do
+      Namespace::Type.hierarchy_class.to_s.should == "Namespace::TypeHierarchy"
+      Namespace::Type.hierarchy_class_name.should == "Namespace::TypeHierarchy"
+      Namespace::Type.short_hierarchy_class_name.should == "TypeHierarchy"
+    end
+  end
+
+end
diff --git a/spec/support/models.rb b/spec/support/models.rb
index 8bff5f1c..83cb1e52 100644
--- a/spec/support/models.rb
+++ b/spec/support/models.rb
@@ -65,3 +65,10 @@ class DirectoryLabel < Label
 class CuisineType < ActiveRecord::Base
   acts_as_tree
 end
+
+module Namespace
+  class Type < ActiveRecord::Base
+    acts_as_tree :dependent => :destroy
+    attr_accessible :name
+  end
+end
diff --git a/spec/tag_spec.rb b/spec/tag_spec.rb
index ec5f8679..35f4d986 100644
--- a/spec/tag_spec.rb
+++ b/spec/tag_spec.rb
@@ -244,6 +244,7 @@ def nuke_db
       it "should build hierarchy classname correctly" do
         Tag.hierarchy_class.to_s.should == "TagHierarchy"
         Tag.hierarchy_class_name.should == "TagHierarchy"
+        Tag.short_hierarchy_class_name.should == "TagHierarchy"
       end
 
       it "should have a correct parent column name" do