From PSU, a really interesting article with facts stating the benefits for streams that contain large woody debris.
https://extension.psu.edu/benefits-of-large-woody-debris-in-streams?fbclid=IwAR3xBZQ1tmVC3_0M12TLqT_BmjmqLGvEdmsqRBApEkBKM5HV9dBdwGoEsWw#.Xd6ZKkUSyy4.facebook
https://extension.psu.edu/benefits-of-large-woody-debris-in-streams?fbclid=IwAR3xBZQ1tmVC3_0M12TLqT_BmjmqLGvEdmsqRBApEkBKM5HV9dBdwGoEsWw#.Xd6ZKkUSyy4.facebook