sap ladder efficiency

[jimsudz]

Has there ever been any research done on the efficiency of sap ladders ? I'm planning to putting in a 6 way star sap ladder for 25-30 taps, just wondering if I'm better off just hanging buckets.

[Monster Maples]

Try this:
http://www.ontariomaple.com/index.php?action=display&cat=38&doc=2004_summary_sap_ladder_project-Final_Rep_June_2304.pdf