diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index 39c2ebd..38d43e5 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -238,15 +238,10 @@ module ApplicationHelper
   end
   
   # Yields the given block for each project with its level in the tree
+  #
+  # Wrapper for Project#project_tree
   def project_tree(projects, &block)
-    ancestors = []
-    projects.sort_by(&:lft).each do |project|
-      while (ancestors.any? && !project.is_descendant_of?(ancestors.last)) 
-        ancestors.pop
-      end
-      yield project, ancestors.size
-      ancestors << project
-    end
+    Project.project_tree(projects, &block)
   end
   
   def project_nested_ul(projects, &block)
diff --git a/app/models/project.rb b/app/models/project.rb
index 000efa7..16c9744 100644
--- a/app/models/project.rb
+++ b/app/models/project.rb
@@ -565,6 +565,18 @@ class Project < ActiveRecord::Base
       return nil
     end
   end
+
+  # Yields the given block for each project with its level in the tree
+  def self.project_tree(projects, &block)
+    ancestors = []
+    projects.sort_by(&:lft).each do |project|
+      while (ancestors.any? && !project.is_descendant_of?(ancestors.last)) 
+        ancestors.pop
+      end
+      yield project, ancestors.size
+      ancestors << project
+    end
+  end
   
   private