diff --git a/src/options.rs b/src/options.rs
index e12b349fc2ff9d016d0a19077820ef4f76e576dc..a27be6bb6238be369d7b2c76b95fbcd4b01fd1ea 100644
--- a/src/options.rs
+++ b/src/options.rs
@@ -240,6 +240,9 @@ impl View {
         else if matches.opt_present("time") {
             Err(Misfire::Useless("time", false, "long"))
         }
+        else if matches.opt_present("tree") {
+            Err(Misfire::Useless("tree", false, "long"))
+        }
         else if matches.opt_present("oneline") {
             if matches.opt_present("across") {
                 Err(Misfire::Useless("across", true, "oneline"))