diff --git a/sphinx/application.py b/sphinx/application.py
index 6ada00b6d..a8049b933 100644
--- a/sphinx/application.py
+++ b/sphinx/application.py
@@ -106,6 +106,7 @@ builtin_extensions = (
     'sphinx.environment.collectors.dependencies',
     'sphinx.environment.collectors.asset',
     'sphinx.environment.collectors.metadata',
+    'sphinx.environment.collectors.title',
 )  # type: Tuple[unicode, ...]
 
 CONFIG_FILENAME = 'conf.py'
diff --git a/sphinx/environment/__init__.py b/sphinx/environment/__init__.py
index 105c4e208..fd975c4ea 100644
--- a/sphinx/environment/__init__.py
+++ b/sphinx/environment/__init__.py
@@ -46,7 +46,6 @@ from sphinx.util.parallel import ParallelTasks, parallel_available, make_chunks
 from sphinx.util.websupport import is_commentable
 from sphinx.errors import SphinxError, ExtensionError
 from sphinx.versioning import add_uids, merge_doctrees
-from sphinx.transforms import SphinxContentsFilter
 from sphinx.deprecation import RemovedInSphinx20Warning
 from sphinx.environment.managers.indexentries import IndexEntries
 from sphinx.environment.managers.toctree import Toctree
@@ -312,8 +311,6 @@ class BuildEnvironment(object):
         if docname in self.all_docs:
             self.all_docs.pop(docname, None)
             self.reread_always.discard(docname)
-            self.titles.pop(docname, None)
-            self.longtitles.pop(docname, None)
 
             for version, changes in self.versionchanges.items():
                 new = [change for change in changes if change[1] != docname]
@@ -337,8 +334,6 @@ class BuildEnvironment(object):
             self.all_docs[docname] = other.all_docs[docname]
             if docname in other.reread_always:
                 self.reread_always.add(docname)
-            self.titles[docname] = other.titles[docname]
-            self.longtitles[docname] = other.longtitles[docname]
 
         for version, changes in other.versionchanges.items():
             self.versionchanges.setdefault(version, []).extend(
@@ -723,7 +718,6 @@ class BuildEnvironment(object):
             doctree = pub.document
 
         # post-processing
-        self.create_title_from(docname, doctree)
         for manager in itervalues(self.managers):
             manager.process_doc(docname, doctree)
         for domain in itervalues(self.domains):
@@ -848,32 +842,6 @@ class BuildEnvironment(object):
              self.ref_context.get('py:module'),
              self.temp_data.get('object'), node.astext()))
 
-    # post-processing of read doctrees
-
-    def create_title_from(self, docname, document):
-        # type: (unicode, nodes.Node) -> None
-        """Add a title node to the document (just copy the first section title),
-        and store that title in the environment.
-        """
-        titlenode = nodes.title()
-        longtitlenode = titlenode
-        # explicit title set with title directive; use this only for
-        # the <title> tag in HTML output
-        if 'title' in document:
-            longtitlenode = nodes.title()
-            longtitlenode += nodes.Text(document['title'])
-        # look for first section title and use that as the title
-        for node in document.traverse(nodes.section):
-            visitor = SphinxContentsFilter(document)
-            node[0].walkabout(visitor)
-            titlenode += visitor.get_entry_text()
-            break
-        else:
-            # document has no title
-            titlenode += nodes.Text('<no title>')
-        self.titles[docname] = titlenode
-        self.longtitles[docname] = longtitlenode
-
     def note_toctree(self, docname, toctreenode):
         # type: (unicode, addnodes.toctree) -> None
         """Note a TOC tree directive in a document and gather information about
diff --git a/sphinx/environment/collectors/title.py b/sphinx/environment/collectors/title.py
new file mode 100644
index 000000000..a5316fe94
--- /dev/null
+++ b/sphinx/environment/collectors/title.py
@@ -0,0 +1,65 @@
+# -*- coding: utf-8 -*-
+"""
+    sphinx.environment.collectors.title
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+    The title collector components for sphinx.environment.
+
+    :copyright: Copyright 2007-2016 by the Sphinx team, see AUTHORS.
+    :license: BSD, see LICENSE for details.
+"""
+
+from docutils import nodes
+
+from sphinx.environment.collectors import EnvironmentCollector
+from sphinx.transforms import SphinxContentsFilter
+
+if False:
+    # For type annotation
+    from docutils import nodes  # NOQA
+    from sphinx.sphinx import Sphinx  # NOQA
+    from sphinx.environment import BuildEnvironment  # NOQA
+
+
+class TitleCollector(EnvironmentCollector):
+    """title collector for sphinx.environment."""
+
+    def clear_doc(self, app, env, docname):
+        # type: (Sphinx, BuildEnvironment, unicode) -> None
+        env.titles.pop(docname, None)
+        env.longtitles.pop(docname, None)
+
+    def merge_other(self, app, env, docnames, other):
+        # type: (Sphinx, BuildEnvironment, Set[unicode], BuildEnvironment) -> None
+        for docname in docnames:
+            env.titles[docname] = other.titles[docname]
+            env.longtitles[docname] = other.longtitles[docname]
+
+    def process_doc(self, app, doctree):
+        # type: (Sphinx, nodes.Node) -> None
+        """Add a title node to the document (just copy the first section title),
+        and store that title in the environment.
+        """
+        titlenode = nodes.title()
+        longtitlenode = titlenode
+        # explicit title set with title directive; use this only for
+        # the <title> tag in HTML output
+        if 'title' in doctree:
+            longtitlenode = nodes.title()
+            longtitlenode += nodes.Text(doctree['title'])
+        # look for first section title and use that as the title
+        for node in doctree.traverse(nodes.section):
+            visitor = SphinxContentsFilter(doctree)
+            node[0].walkabout(visitor)
+            titlenode += visitor.get_entry_text()
+            break
+        else:
+            # document has no title
+            titlenode += nodes.Text('<no title>')
+        app.env.titles[app.env.docname] = titlenode
+        app.env.longtitles[app.env.docname] = longtitlenode
+
+
+def setup(app):
+    # type: (Sphinx) -> None
+    app.add_env_collector(TitleCollector)