Looking on the internet deeply has found these results:

smaller tree depth is the most popular phrase on the web.

less tree depth 1179 results on the web	smaller tree depth 15,220 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
No paper bills, less tree murder.	That tree used to be a smaller tree. That tree used to be a smaller tree.

less tree depth

1179 results on the web

smaller tree depth

15,220 results on the web

More popular!