diff --git a/include/geos/index/strtree/TemplateSTRtree.h b/include/geos/index/strtree/TemplateSTRtree.h
index 32263289b1..6960ddf098 100644
--- a/include/geos/index/strtree/TemplateSTRtree.h
+++ b/include/geos/index/strtree/TemplateSTRtree.h
@@ -206,7 +206,6 @@ class TemplateSTRtreeImpl {
     /** Determine the two closest items in the tree using distance metric `distance`. */
     template<typename ItemDistance>
     std::pair<ItemType, ItemType> nearestNeighbour() {
-        ItemDistance id;
         return nearestNeighbour(*this);
     }