diff --git a/plants_lib/init.lua b/plants_lib/init.lua
index a8bddd0..88d776a 100644
--- a/plants_lib/init.lua
+++ b/plants_lib/init.lua
@@ -190,8 +190,8 @@ function plantslib:search_for_surfaces(minp, maxp, biomedef, node_or_function_or
 							minetest.registered_nodes[node_or_function_or_model] then
 							minetest.add_node(p_top, { name = node_or_function_or_model })
 							spawned = true
-						elseif type(loadstring("return "..node_or_function_or_model)) == "function" then
-							assert(loadstring(node_or_function_or_model.."("..dump_pos(pos)..")"))()
+						elseif pcall(loadstring(("return type(%s) == \"function\" and %s(%s)"):
+							format(node_or_function_or_model, node_or_function_or_model, dump_pos(pos)))) then
 							spawned = true
 						else
 							print("Ignored invalid definition for object "..dump(node_or_function_or_model).." that was pointed at {"..dump(pos).."}")