diff --git a/include/osgTerrain/GeometryTechnique b/include/osgTerrain/GeometryTechnique
index a02c4d969..70cb90df0 100644
--- a/include/osgTerrain/GeometryTechnique
+++ b/include/osgTerrain/GeometryTechnique
@@ -57,10 +57,6 @@ class OSGTERRAIN_EXPORT GeometryTechnique : public TerrainTechnique
 
         virtual void cleanSceneGraph();
 
-        virtual void dirty();
-        
-        
-        
         void setFilterBias(float filterBias);
         float getFilterBias() const { return _filterBias; }
         
diff --git a/include/osgTerrain/TerrainTechnique b/include/osgTerrain/TerrainTechnique
index d5dbe5d13..e7f47854e 100644
--- a/include/osgTerrain/TerrainTechnique
+++ b/include/osgTerrain/TerrainTechnique
@@ -51,20 +51,15 @@ class OSGTERRAIN_EXPORT TerrainTechnique : public osg::Object
         /** Traverse the terrain subgraph.*/
         virtual void traverse(osg::NodeVisitor& nv);
 
-        /** Dirty so that cached data structures will be updated on next use.*/
-        virtual void dirty();
-
-        /** Return true if cached data structures need updating.*/
-        virtual bool isDirty() const { return _dirty; }
-
     protected:
+    
+        void setDirty(bool dirty);
 
         virtual ~TerrainTechnique();
         
         friend class osgTerrain::TerrainTile;
 
         TerrainTile*    _terrainTile;
-        bool            _dirty;
 
 };
 
diff --git a/include/osgTerrain/TerrainTile b/include/osgTerrain/TerrainTile
index ec38787f2..d4c8a761c 100644
--- a/include/osgTerrain/TerrainTile
+++ b/include/osgTerrain/TerrainTile
@@ -160,6 +160,11 @@ class OSGTERRAIN_EXPORT TerrainTile : public osg::Group
         /** Get whether the TeatBoundariesToValidDataAsDefaultValue hint.*/
         bool getTreatBoundariesToValidDataAsDefaultValue() const { return _treatBoundariesToValidDataAsDefaultValue; }
 
+        /** Set the dirty flag on/off.*/
+        void setDirty(bool dirty);
+
+        /** return true if the tile is dirty and needs to be updated,*/
+        bool getDirty() const { return _dirty; }
 
         /** Compute the bounding volume of the terrain by computing the union of the bounding volumes of all layers.*/
         virtual osg::BoundingSphere computeBound() const;
@@ -168,12 +173,14 @@ class OSGTERRAIN_EXPORT TerrainTile : public osg::Group
 
         virtual ~TerrainTile();
 
+
         typedef std::vector< osg::ref_ptr<Layer> > Layers;
 
         friend class Terrain;
 
         Terrain*                            _terrain;
-
+        
+        bool                                _dirty;
         bool                                _hasBeenTraversal;
         
         TileID                              _tileID;
diff --git a/src/osgTerrain/GeometryTechnique.cpp b/src/osgTerrain/GeometryTechnique.cpp
index 62e1527d6..6eb03c344 100644
--- a/src/osgTerrain/GeometryTechnique.cpp
+++ b/src/osgTerrain/GeometryTechnique.cpp
@@ -101,7 +101,7 @@ void GeometryTechnique::setFilterMatrixAs(FilterType filterType)
 
 void GeometryTechnique::init()
 {
-    // osg::notify(osg::NOTICE)<<"Doing GeometryTechnique::init()"<<std::endl;
+    osg::notify(osg::INFO)<<"Doing GeometryTechnique::init()"<<std::endl;
     
     if (!_terrainTile) return;
 
@@ -120,8 +120,6 @@ void GeometryTechnique::init()
 
     if (buffer._transform.valid()) buffer._transform->setThreadSafeRefUnref(true);
 
-    _dirty = false;    
-
     swapBuffers();
 }
 
@@ -777,7 +775,7 @@ void GeometryTechnique::traverse(osg::NodeVisitor& nv)
     // if app traversal update the frame count.
     if (nv.getVisitorType()==osg::NodeVisitor::UPDATE_VISITOR)
     {
-        if (_dirty) _terrainTile->init();
+        if (_terrainTile->getDirty()) _terrainTile->init();
 
         osgUtil::UpdateVisitor* uv = dynamic_cast<osgUtil::UpdateVisitor*>(&nv);
         if (uv)
@@ -798,7 +796,7 @@ void GeometryTechnique::traverse(osg::NodeVisitor& nv)
     }
 
 
-    if (_dirty) 
+    if (_terrainTile->getDirty()) 
     {
         osg::notify(osg::INFO)<<"******* Doing init ***********"<<std::endl;
         _terrainTile->init();
@@ -813,8 +811,3 @@ void GeometryTechnique::cleanSceneGraph()
 {
 }
 
-void GeometryTechnique::dirty()
-{
-    TerrainTechnique::dirty();
-}
-
diff --git a/src/osgTerrain/Terrain.cpp b/src/osgTerrain/Terrain.cpp
index 318741cad..abb508fa5 100644
--- a/src/osgTerrain/Terrain.cpp
+++ b/src/osgTerrain/Terrain.cpp
@@ -79,14 +79,7 @@ void Terrain::dirtyRegisteredTiles()
         itr != _terrainTileSet.end();
         ++itr)
     {
-        TerrainTechnique* tt = const_cast<TerrainTile*>(*itr)->getTerrainTechnique();
-    if(tt)
-    {
-        tt->dirty();
-
-            // Force recreation of Geometry
-        // const_cast<TerrainTile*>(*itr)->init();
-    }
+        (const_cast<TerrainTile*>(*itr))->setDirty(true);
     }
 }
 
diff --git a/src/osgTerrain/TerrainTechnique.cpp b/src/osgTerrain/TerrainTechnique.cpp
index fd4768bb2..3cb7a46c2 100644
--- a/src/osgTerrain/TerrainTechnique.cpp
+++ b/src/osgTerrain/TerrainTechnique.cpp
@@ -17,16 +17,14 @@
 using namespace osgTerrain;
 
 TerrainTechnique::TerrainTechnique():
-    _terrainTile(0),
-    _dirty(true)
+    _terrainTile(0)
 {
     setThreadSafeRefUnref(true);
 }
 
 TerrainTechnique::TerrainTechnique(const TerrainTechnique& TerrainTechnique,const osg::CopyOp& copyop):
     osg::Object(TerrainTechnique,copyop),
-    _terrainTile(0),
-    _dirty(true)
+    _terrainTile(0)
 {
 }
 
@@ -37,8 +35,6 @@ TerrainTechnique::~TerrainTechnique()
 void TerrainTechnique::init()
 {
     osg::notify(osg::NOTICE)<<className()<<"::initialize(..) not implementated yet"<<std::endl;
-    
-    _dirty = false;
 }
 
 void TerrainTechnique::update(osgUtil::UpdateVisitor* uv)
@@ -58,12 +54,6 @@ void TerrainTechnique::cleanSceneGraph()
     osg::notify(osg::NOTICE)<<className()<<"::cleanSceneGraph(..) not implementated yet"<<std::endl;
 }
 
-void TerrainTechnique::dirty()
-{
-    // osg::notify(osg::NOTICE)<<className()<<"::dirty(..) not implemented yet"<<std::endl;    
-    _dirty = true;
-}
-
 void TerrainTechnique::traverse(osg::NodeVisitor& nv)
 {
     if (!_terrainTile) return;
@@ -71,7 +61,7 @@ void TerrainTechnique::traverse(osg::NodeVisitor& nv)
     // if app traversal update the frame count.
     if (nv.getVisitorType()==osg::NodeVisitor::UPDATE_VISITOR)
     {
-        if (_dirty) _terrainTile->init();
+        if (_terrainTile->getDirty()) _terrainTile->init();
 
         osgUtil::UpdateVisitor* uv = dynamic_cast<osgUtil::UpdateVisitor*>(&nv);
         if (uv)
@@ -91,7 +81,7 @@ void TerrainTechnique::traverse(osg::NodeVisitor& nv)
         }
     }
 
-    if (_dirty) _terrainTile->init();
+    if (_terrainTile->getDirty()) _terrainTile->init();
 
     // otherwise fallback to the Group::traverse()
     _terrainTile->osg::Group::traverse(nv);
diff --git a/src/osgTerrain/TerrainTile.cpp b/src/osgTerrain/TerrainTile.cpp
index feb84f18d..1fffca7bc 100644
--- a/src/osgTerrain/TerrainTile.cpp
+++ b/src/osgTerrain/TerrainTile.cpp
@@ -23,9 +23,9 @@ TerrainTile::TerrainTile():
     _terrain(0),
     _hasBeenTraversal(false),
     _requiresNormals(true),
-    _treatBoundariesToValidDataAsDefaultValue(false)
+    _treatBoundariesToValidDataAsDefaultValue(false),
+    _dirty(false)
 {
-    //setNumChildrenRequiringUpdateTraversal(1);
     setThreadSafeRefUnref(true);
 }
 
@@ -36,11 +36,13 @@ TerrainTile::TerrainTile(const TerrainTile& terrain,const osg::CopyOp& copyop):
     _elevationLayer(terrain._elevationLayer),
     _colorLayers(terrain._colorLayers),
     _requiresNormals(terrain._requiresNormals),
-    _treatBoundariesToValidDataAsDefaultValue(terrain._treatBoundariesToValidDataAsDefaultValue)
+    _treatBoundariesToValidDataAsDefaultValue(terrain._treatBoundariesToValidDataAsDefaultValue),
+    _dirty(false)
 {
-    //setNumChildrenRequiringUpdateTraversal(getNumChildrenRequiringUpdateTraversal()+1);
-    
-    if (terrain.getTerrainTechnique()) setTerrainTechnique(dynamic_cast<TerrainTechnique*>(terrain.getTerrainTechnique()->cloneType()));
+    if (terrain.getTerrainTechnique()) 
+    {
+        setTerrainTechnique(dynamic_cast<TerrainTechnique*>(terrain.getTerrainTechnique()->cloneType()));
+    }
 }
 
 TerrainTile::~TerrainTile()
@@ -118,9 +120,11 @@ void TerrainTile::traverse(osg::NodeVisitor& nv)
 
 void TerrainTile::init()
 {
-    if (_terrainTechnique.valid() && _terrainTechnique->isDirty())
+    if (_terrainTechnique.valid() && getDirty())
     {
         _terrainTechnique->init();
+        
+        setDirty(false);
     }    
 }
 
@@ -128,14 +132,42 @@ void TerrainTile::setTerrainTechnique(TerrainTechnique* terrainTechnique)
 {
     if (_terrainTechnique == terrainTechnique) return; 
 
-    if (_terrainTechnique.valid()) _terrainTechnique->_terrainTile = 0;
+    int dirtyDelta = _dirty ? -1 : 0;
+
+    if (_terrainTechnique.valid()) 
+    {
+        _terrainTechnique->_terrainTile = 0;
+    }
 
     _terrainTechnique = terrainTechnique;
     
-    if (_terrainTechnique.valid()) _terrainTechnique->_terrainTile = this;
+    if (_terrainTechnique.valid()) 
+    {
+        _terrainTechnique->_terrainTile = this;
+        ++dirtyDelta;        
+    }
     
+    if (dirtyDelta>0) setDirty(true);
+    else if (dirtyDelta<0) setDirty(false);
 }
 
+void TerrainTile::setDirty(bool dirty)
+{
+    if (_dirty==dirty) return;
+
+    _dirty = dirty;
+
+    if (_dirty)
+    {
+        setNumChildrenRequiringUpdateTraversal(getNumChildrenRequiringUpdateTraversal()+1);
+    }
+    else if (getNumChildrenRequiringUpdateTraversal()>0) 
+    {
+        setNumChildrenRequiringUpdateTraversal(getNumChildrenRequiringUpdateTraversal()-1);
+    }
+}
+
+
 
 void TerrainTile::setElevationLayer(Layer* layer)
 {