Table:
text: Operation Hardtack I
Tests
Hardtack I Tests
Name_ Location_ Elevation_Height Delivery Purpose Yield
Aspen Bikini, Namu (Charlie) 0 + metres (ft) Barge Weapons development 319 kt
Walnut Enewetak, Enjebi (Janet) 0 + metres (ft) Barge Weapons development 1.5 Mt
Linden Enewetak, Runit (Yvonne) 0 + metres (ft) Barge Weapons development 11 kt
Redwood Bikini, Yurochi aka Irioj (Dog) 0 + metres (ft) Barge Weapons development 412 kt
Elder Enewetak, Enjebi (Janet) 0 + metres (ft) Barge Weapons development 880 kt
Oak Enewetak, Bogallua (Alice) 0 + metres (ft) Barge Weapons development 8.9 Mt
Hickory Bikini, Eninmen (Tare) 0 + metres (ft) Barge Weapons development 14 kt
Sequoia Enewetak, Runit (Yvonne) 0 + metres (ft) Barge Weapons development 5.2 kt

Question: What is the purpose of oak under Operation Hardtack I?