diff --git a/src/lib/adblock/adblocksearchtree.cpp b/src/lib/adblock/adblocksearchtree.cpp
index 68f8a5180..2e3c2e648 100644
--- a/src/lib/adblock/adblocksearchtree.cpp
+++ b/src/lib/adblock/adblocksearchtree.cpp
@@ -25,6 +25,17 @@ AdBlockSearchTree::AdBlockSearchTree()
 {
 }
 
+AdBlockSearchTree::~AdBlockSearchTree()
+{
+    deleteNode(m_root);
+}
+
+void AdBlockSearchTree::clear()
+{
+    deleteNode(m_root);
+    m_root = new Node;
+}
+
 bool AdBlockSearchTree::add(const AdBlockRule* rule)
 {
     if (rule->m_type != AdBlockRule::StringContainsMatchRule) {
@@ -58,7 +69,7 @@ bool AdBlockSearchTree::add(const AdBlockRule* rule)
     return true;
 }
 
-const AdBlockRule* AdBlockSearchTree::find(const QNetworkRequest &request, const QString &domain, const QString &string)
+const AdBlockRule* AdBlockSearchTree::find(const QNetworkRequest &request, const QString &domain, const QString &string) const
 {
     int len = string.size();
 
@@ -76,7 +87,7 @@ const AdBlockRule* AdBlockSearchTree::find(const QNetworkRequest &request, const
     return 0;
 }
 
-const AdBlockRule* AdBlockSearchTree::prefixSearch(const QNetworkRequest &request, const QString &domain, const QString &urlString, const QString &string)
+const AdBlockRule* AdBlockSearchTree::prefixSearch(const QNetworkRequest &request, const QString &domain, const QString &urlString, const QString &string) const
 {
     int len = string.size();
 
@@ -127,8 +138,3 @@ void AdBlockSearchTree::deleteNode(AdBlockSearchTree::Node* node)
 
     delete node;
 }
-
-AdBlockSearchTree::~AdBlockSearchTree()
-{
-    deleteNode(m_root);
-}
diff --git a/src/lib/adblock/adblocksearchtree.h b/src/lib/adblock/adblocksearchtree.h
index f22c0490f..f6b9c4e99 100644
--- a/src/lib/adblock/adblocksearchtree.h
+++ b/src/lib/adblock/adblocksearchtree.h
@@ -33,8 +33,10 @@ public:
     explicit AdBlockSearchTree();
     ~AdBlockSearchTree();
 
+    void clear();
+
     bool add(const AdBlockRule* rule);
-    const AdBlockRule* find(const QNetworkRequest &request, const QString &domain, const QString &string);
+    const AdBlockRule* find(const QNetworkRequest &request, const QString &domain, const QString &string) const;
 
 private:
     struct Node {
@@ -46,7 +48,7 @@ private:
     };
 
     const AdBlockRule* prefixSearch(const QNetworkRequest &request, const QString &domain,
-                                    const QString &urlString, const QString &string);
+                                    const QString &urlString, const QString &string) const;
 
     void deleteNode(Node* node);
 
diff --git a/src/lib/adblock/adblocksubscription.cpp b/src/lib/adblock/adblocksubscription.cpp
index 68aa4d854..29eb09517 100644
--- a/src/lib/adblock/adblocksubscription.cpp
+++ b/src/lib/adblock/adblocksubscription.cpp
@@ -58,8 +58,6 @@
 AdBlockSubscription::AdBlockSubscription(const QString &title, QObject* parent)
     : QObject(parent)
     , m_reply(0)
-    , m_networkBlockTree(0)
-    , m_networkExceptionTree(0)
     , m_title(title)
     , m_updated(false)
 {
@@ -203,11 +201,11 @@ void AdBlockSubscription::saveDownloadedData(const QByteArray &data)
 
 const AdBlockRule* AdBlockSubscription::match(const QNetworkRequest &request, const QString &urlDomain, const QString &urlString) const
 {
-    if (m_networkExceptionTree->find(request, urlDomain, urlString)) {
+    if (m_networkExceptionTree.find(request, urlDomain, urlString)) {
         return 0;
     }
 
-    if (const AdBlockRule* rule = m_networkBlockTree->find(request, urlDomain, urlString)) {
+    if (const AdBlockRule* rule = m_networkBlockTree.find(request, urlDomain, urlString)) {
         return rule;
     }
 
@@ -377,19 +375,15 @@ const AdBlockRule* AdBlockSubscription::replaceRule(AdBlockRule* rule, int offse
 
 void AdBlockSubscription::populateCache()
 {
+    m_networkExceptionTree.clear();
     m_networkExceptionRules.clear();
+    m_networkBlockTree.clear();
     m_networkBlockRules.clear();
     m_domainRestrictedCssRules.clear();
     m_elementHidingRules.clear();
     m_documentRules.clear();
     m_elemhideRules.clear();
 
-    delete m_networkBlockTree;
-    delete m_networkExceptionTree;
-
-    m_networkBlockTree = new AdBlockSearchTree;
-    m_networkExceptionTree = new AdBlockSearchTree;
-
     // Apparently, excessive amount of selectors for one CSS rule is not what WebKit likes.
     // (In my testings, 4931 is the number that makes it crash)
     // So let's split it by 1000 selectors...
@@ -423,12 +417,12 @@ void AdBlockSubscription::populateCache()
             m_elemhideRules.append(rule);
         }
         else if (rule->isException()) {
-            if (!m_networkExceptionTree->add(rule)) {
+            if (!m_networkExceptionTree.add(rule)) {
                 m_networkExceptionRules.append(rule);
             }
         }
         else {
-            if (!m_networkBlockTree->add(rule)) {
+            if (!m_networkBlockTree.add(rule)) {
                 m_networkBlockRules.append(rule);
             }
         }
@@ -443,8 +437,6 @@ void AdBlockSubscription::populateCache()
 AdBlockSubscription::~AdBlockSubscription()
 {
     qDeleteAll(m_rules);
-    delete m_networkBlockTree;
-    delete m_networkExceptionTree;
 }
 
 // AdBlockCustomList
diff --git a/src/lib/adblock/adblocksubscription.h b/src/lib/adblock/adblocksubscription.h
index a931544d1..3aee142c5 100644
--- a/src/lib/adblock/adblocksubscription.h
+++ b/src/lib/adblock/adblocksubscription.h
@@ -51,12 +51,12 @@
 
 #include "qz_namespace.h"
 #include "adblockrule.h"
+#include "adblocksearchtree.h"
 
 class QNetworkRequest;
 class QNetworkReply;
 class QUrl;
 
-class AdBlockSearchTree;
 class FollowRedirectReply;
 
 class QT_QUPZILLA_EXPORT AdBlockSubscription : public QObject
@@ -124,8 +124,8 @@ protected:
     QVector<const AdBlockRule*> m_documentRules;
     QVector<const AdBlockRule*> m_elemhideRules;
 
-    AdBlockSearchTree* m_networkBlockTree;
-    AdBlockSearchTree* m_networkExceptionTree;
+    AdBlockSearchTree m_networkBlockTree;
+    AdBlockSearchTree m_networkExceptionTree;
 
 private:
     QString m_title;