diff --git a/src/nlsat/nlsat_params.pyg b/src/nlsat/nlsat_params.pyg
index 1ab305984..d63a96e91 100644
--- a/src/nlsat/nlsat_params.pyg
+++ b/src/nlsat/nlsat_params.pyg
@@ -23,6 +23,6 @@ def_module_params('nlsat',
                           ('zero_disc', BOOL, False, "add_zero_assumption to the vanishing discriminant."),
                           ('known_sat_assignment_file_name', STRING, "", "the file name of a known solution: used for debugging only"),
                           ('lws', BOOL, True, "apply levelwise."),
-                          ('lws_spt_threshold', UINT, 2, "minimum both-side polynomial count to apply spanning tree optimization; < 2 disables spanning tree"),
+                          ('lws_spt_threshold', UINT, 4, "minimum both-side polynomial count to apply spanning tree optimization; < 2 disables spanning tree"),
                           ('canonicalize', BOOL, True, "canonicalize polynomials.")
                           ))