diff --git a/lib/gollum/git_access.rb b/lib/gollum/git_access.rb
index 3df2bc89..7e67010b 100644
--- a/lib/gollum/git_access.rb
+++ b/lib/gollum/git_access.rb
@@ -158,7 +158,9 @@ module Gollum
     def tree!(sha)
       tree  = @repo.git.native(:ls_tree,
         {:r => true, :l => true, :z => true}, sha)
-      tree.force_encoding("UTF-8")
+      if tree.respond_to?(:force_encoding)
+        tree.force_encoding("UTF-8")
+      end
       items = tree.split("\0").inject([]) do |memo, line|
         memo << parse_tree_line(line)
       end