diff --git a/src/libslic3r/Fill/Lightning/Generator.cpp b/src/libslic3r/Fill/Lightning/Generator.cpp
index b4c07a338..e226fbbab 100644
--- a/src/libslic3r/Fill/Lightning/Generator.cpp
+++ b/src/libslic3r/Fill/Lightning/Generator.cpp
@@ -125,6 +125,8 @@ void Generator::generateTrees(const PrintObject &print_object, const std::functi
         if (const BoundingBox &outlines_locator_bbox = outlines_locator.bbox(); outlines_locator_bbox.defined)
             below_outlines_bbox.merge(outlines_locator_bbox);
 
+        below_outlines_bbox.merge(get_extents(current_lightning_layer.tree_roots).inflated(SCALED_EPSILON));
+
         outlines_locator.set_bbox(below_outlines_bbox);
         outlines_locator.create(below_outlines, locator_cell_size);
 
diff --git a/src/libslic3r/Fill/Lightning/TreeNode.hpp b/src/libslic3r/Fill/Lightning/TreeNode.hpp
index fdb80d2e6..81c63f7f6 100644
--- a/src/libslic3r/Fill/Lightning/TreeNode.hpp
+++ b/src/libslic3r/Fill/Lightning/TreeNode.hpp
@@ -269,6 +269,9 @@ protected:
 
     std::optional<Point> m_last_grounding_location;  //<! The last known grounding location, see 'getLastGroundingLocation()'.
 
+    friend BoundingBox get_extents(const NodeSPtr &root_node);
+    friend BoundingBox get_extents(const std::vector<NodeSPtr> &tree_roots);
+
 #ifdef LIGHTNING_TREE_NODE_DEBUG_OUTPUT
     friend void export_to_svg(const NodeSPtr &root_node, Slic3r::SVG &svg);
     friend void export_to_svg(const std::string &path, const Polygons &contour, const std::vector<NodeSPtr> &root_nodes);
@@ -278,6 +281,23 @@ protected:
 bool inside(const Polygons &polygons, const Point &p);
 bool lineSegmentPolygonsIntersection(const Point& a, const Point& b, const EdgeGrid::Grid& outline_locator, Point& result, coord_t within_max_dist);
 
+inline BoundingBox get_extents(const NodeSPtr &root_node)
+{
+    BoundingBox bbox;
+    for (const NodeSPtr &children : root_node->m_children)
+        bbox.merge(get_extents(children));
+    bbox.merge(root_node->getLocation());
+    return bbox;
+}
+
+inline BoundingBox get_extents(const std::vector<NodeSPtr> &tree_roots)
+{
+    BoundingBox bbox;
+    for (const NodeSPtr &root_node : tree_roots)
+        bbox.merge(get_extents(root_node));
+    return bbox;
+}
+
 #ifdef LIGHTNING_TREE_NODE_DEBUG_OUTPUT
 void export_to_svg(const NodeSPtr &root_node, SVG &svg);
 void export_to_svg(const std::string &path, const Polygons &contour, const std::vector<NodeSPtr> &root_nodes);