diff --git a/src/libslic3r/Clipper2Utils.cpp b/src/libslic3r/Clipper2Utils.cpp
index 53b074fe7..2f62d77ba 100644
--- a/src/libslic3r/Clipper2Utils.cpp
+++ b/src/libslic3r/Clipper2Utils.cpp
@@ -79,6 +79,19 @@ static ExPolygons PolyTreeToExPolygons(Clipper2Lib::PolyTree64 &&polytree)
     return retval;
 }
 
+Clipper2Lib::Paths64 Slic3rPolygons_to_Paths64(const Polygons &in)
+{
+    Clipper2Lib::Paths64 out;
+    out.reserve(in.size());
+    for (const Polygon &poly : in) {
+        Clipper2Lib::Path64 path;
+        path.reserve(poly.points.size());
+        for (const Slic3r::Point &point : poly.points) path.emplace_back(std::move(Clipper2Lib::Point64(point.x(), point.y())));
+        out.emplace_back(std::move(path));
+    }
+    return out;
+}
+
 Clipper2Lib::Paths64 Slic3rExPolygons_to_Paths64(const ExPolygons& in)
 {
     Clipper2Lib::Paths64 out;
@@ -119,10 +132,10 @@ Slic3r::Polylines intersection_pl_2(const Slic3r::Polylines& subject, const Slic
 Slic3r::Polylines  diff_pl_2(const Slic3r::Polylines& subject, const Slic3r::Polygons& clip)
     { return _clipper2_pl_open(Clipper2Lib::ClipType::Difference, subject, clip); }
 
-ExPolygons union_ex2(const ExPolygons& expolygons)
+ExPolygons union_ex2(const Polygons& polygons)
 {
     Clipper2Lib::Clipper64 c;
-    c.AddSubject(Slic3rExPolygons_to_Paths64(expolygons));
+    c.AddSubject(Slic3rPolygons_to_Paths64(polygons));
 
     Clipper2Lib::ClipType ct = Clipper2Lib::ClipType::Union;
     Clipper2Lib::FillRule fr = Clipper2Lib::FillRule::NonZero;
@@ -134,4 +147,18 @@ ExPolygons union_ex2(const ExPolygons& expolygons)
     return results;
 }
 
+ExPolygons union_ex2(const ExPolygons &expolygons)
+{
+    Clipper2Lib::Clipper64 c;
+    c.AddSubject(Slic3rExPolygons_to_Paths64(expolygons));
+
+    Clipper2Lib::ClipType   ct = Clipper2Lib::ClipType::Union;
+    Clipper2Lib::FillRule   fr = Clipper2Lib::FillRule::NonZero;
+    Clipper2Lib::PolyTree64 solution;
+    c.Execute(ct, fr, solution);
+
+    ExPolygons results = PolyTreeToExPolygons(std::move(solution));
+
+    return results;
+}
 }
\ No newline at end of file
diff --git a/src/libslic3r/Clipper2Utils.hpp b/src/libslic3r/Clipper2Utils.hpp
index a612512f7..cd6e209fa 100644
--- a/src/libslic3r/Clipper2Utils.hpp
+++ b/src/libslic3r/Clipper2Utils.hpp
@@ -8,6 +8,7 @@ namespace Slic3r {
 
 Slic3r::Polylines  intersection_pl_2(const Slic3r::Polylines& subject, const Slic3r::Polygons& clip);
 Slic3r::Polylines  diff_pl_2(const Slic3r::Polylines& subject, const Slic3r::Polygons& clip);
+ExPolygons         union_ex2(const Polygons &expolygons);
 ExPolygons         union_ex2(const ExPolygons &expolygons);
 }
 
diff --git a/src/libslic3r/Support/TreeSupport.cpp b/src/libslic3r/Support/TreeSupport.cpp
index ea7671850..d1c44c6cd 100644
--- a/src/libslic3r/Support/TreeSupport.cpp
+++ b/src/libslic3r/Support/TreeSupport.cpp
@@ -3873,24 +3873,20 @@ TreeSupportData::TreeSupportData(const PrintObject &object, coordf_t xy_distance
     m_max_move_distances.resize(object.layers().size(), 0);
     m_layer_outlines.resize(object.layers().size());
     m_layer_outlines_below.resize(object.layer_count());
-    for (std::size_t layer_nr  = 0; layer_nr < object.layers().size(); ++layer_nr) {
-        // BOOST_LOG_TRIVIAL(debug) << "TreeSupportData construct "<< layer_nr<<"/"<<object.layer_count();
-        const Layer* layer = object.get_layer(layer_nr);
+    for (std::size_t layer_nr = 0; layer_nr < object.layers().size(); ++layer_nr) {
+        const Layer *layer             = object.get_layer(layer_nr);
         m_max_move_distances[layer_nr] = layer->height * branch_scale_factor;
-        ExPolygons &outline = m_layer_outlines[layer_nr];
+        ExPolygons &outline            = m_layer_outlines[layer_nr];
         outline.clear();
         outline.reserve(layer->lslices.size());
-        for (const ExPolygon &poly : layer->lslices) { append(outline, to_expolygons( poly.simplify_p(scale_(m_radius_sample_resolution)))); }
-        if (layer_nr % 10 == 0)
-            outline = union_ex(outline);
+        for (const ExPolygon &poly : layer->lslices) { append(outline, union_ex2( poly.simplify_p(scale_(m_radius_sample_resolution)))); }
 
         if (layer_nr == 0)
             m_layer_outlines_below[layer_nr] = outline;
         else {
             m_layer_outlines_below[layer_nr] = m_layer_outlines_below[layer_nr - 1];
             m_layer_outlines_below[layer_nr].insert(m_layer_outlines_below[layer_nr].end(), outline.begin(), outline.end());
-            if (layer_nr%10==0)
-                m_layer_outlines_below[layer_nr] = union_ex2(m_layer_outlines_below[layer_nr]);
+            if (layer_nr % 10 == 0) m_layer_outlines_below[layer_nr] = union_ex2(m_layer_outlines_below[layer_nr]);
         }
     }
 }