How to represent a data tree in SQL?

I’ve bookmarked this slidshare about SQL-Antipatterns, which discusses several alternatives: http://www.slideshare.net/billkarwin/sql-antipatterns-strike-back?src=embed

The recommendation from there is to use a Closure Table (it’s explained in the slides).

Here is the summary (slide 77):

                  | Query Child | Query Subtree | Modify Tree | Ref. Integrity
Adjacency List    |    Easy     |     Hard      |    Easy     |      Yes
Path Enumeration  |    Easy     |     Easy      |    Hard     |      No
Nested Sets       |    Hard     |     Easy      |    Hard     |      No
Closure Table     |    Easy     |     Easy      |    Easy     |      Yes