Which pair completes the statement: 'Douglas Fir and Southern Pine are the two most common species used in cribbing and shimming loads'?

• A. Douglas Pine and Southern Fir
• B. Douglas Fir and Southern Pine
• C. Red Oak and White Pine
• D. Cedar and Maple

Answer: (B)

When selecting lumber for cribbing and shoring, you want pieces that can take heavy loads without crushing or bending and that stay stable under field conditions. The two most common species for this purpose are Douglas Fir and Southern Pine because they combine high strength and stiffness along the grain with good crush resistance, while also being widely available as structural lumber. This means smaller dimensions can safely bear large loads, which is essential for effective cribbing and shimming.

Other options don’t fit this practical needs mix as well. White Pine, for example, is softer and less resistant to crushing, while Cedar and Maple don’t offer the same reliable combination of strength, stiffness, and availability for structural cribbing. Red Oak is strong but not as dimensionally stable for this specific use.