diff --git a/src/aterm-helper.pl b/src/aterm-helper.pl
index 9b2bde7000..f1eb77ee80 100755
--- a/src/aterm-helper.pl
+++ b/src/aterm-helper.pl
@@ -146,8 +146,9 @@ while (<STDIN>) {
         my $value = $2;
         print HEADER "extern ATerm $name;\n";
         print IMPL "ATerm $name = 0;\n";
-        $init .= "    $name = $value;\n";
-    }
+        $init .= "    $name = $value;\n"; 
+        $init .= "    ATprotect(&$name);\n";
+   }
 
     elsif (/^\s*init\s+(\w+)\s*$/) {
         $initFun = $1;
diff --git a/src/libexpr/parser.y b/src/libexpr/parser.y
index c4afb72eac..8706ce0254 100644
--- a/src/libexpr/parser.y
+++ b/src/libexpr/parser.y
@@ -85,6 +85,10 @@ static Expr fixAttrs(bool recursive, ATermList as)
 {
     Tree attrs;
 
+    /* This ATermMap is needed to ensure that the `leaf' fields in the
+       Tree nodes are not garbage collected. */
+    ATermMap gcRoots;
+
     for (ATermIterator i(as); i; ++i) {
         ATermList names, attrPath; Expr src, e; ATerm name, pos;
 
@@ -95,7 +99,9 @@ static Expr fixAttrs(bool recursive, ATermList as)
                     throw ParseError(format("duplicate definition of attribute `%1%' at %2%")
                         % showAttrPath(ATmakeList1(*j)) % showPos(pos));
                 Tree & t(attrs.children[*j]);
-                t.leaf = fromScope ? makeVar(*j) : makeSelect(src, *j);
+                Expr leaf = fromScope ? makeVar(*j) : makeSelect(src, *j);
+                gcRoots.set(leaf, leaf);
+                t.leaf = leaf;
                 t.pos = pos;
                 if (recursive && fromScope) t.recursive = false;
             }