A cord of wood is a volume measurement. A block of wood weighs a different amount depending on its species and how green or wet it is (water increases the weight), so every cord will weigh differently depending on the type of wood. An average cord of seasoned firewood weighs 2,000 to 3,000 pounds and can be carried in a 1/2-ton or 3/4-ton pickup.
To convert volume to weight, you have to have additional information: the density or unit weight of whatever is being converted. The weight will be the number of units times the weight of one unit. The same problem arises in converting American and European cooking recipes: Americans use cups, a volume measurement, whereas Europeans use ounces or grams, a weight measurement. A cup of flour isn't the same weight as a cup of raisins; each ingredient must be individually converted.
A cord is a stack of wood 4 feet by 4 feet by 8 feet, which equals 128 cubic feet. Firewood is commonly sold by the cord (as is pulpwood for making paper). In reality, there will be air in any unit of stacked wood, usually around 25 percent of the space, although it can be more in a stack of uneven logs.
The California Energy Commission's Consumer Energy Center (see Reference section) gives the weight per cord of firewood for various types of wood. Here are typical examples of weights in pounds for a dry cord:
Alder -- 2,000 to 2,600 Sycamore -- 2,390 to 3,080 Maple, Big Leaf -- 2,350 to 3,000 Douglas Fir -- 2,400 to 3,075 Oak, White -- 2,880 to 3,710 Dogwood -- 3,130 to 4,025
The Engineering Toolbox (www.EngineeringToolBox.com) has a table showing specific densities of green and seasoned wood, with weights per cord for a number of species. This shows a significant difference in weight between green (newly cut) and seasoned (dry) wood.
For example they give alder as 2218 pounds/cord when dry, but 3640 when green. Soft maple is 2640 dry, 3950 green; red oak is 3350 dry, 4886 green. This is approximately half as much again for green wood (multiply seasoned wood weight by 1.5 for an average weight increase).
People often want to know the weight of a cord to determine if they can carry a whole cord in their pickup, or if they need to make two trips. A truck is rated for cargo weight (amount you can carry in the bed) and gross vehicle weight (total weight of truck, cargo and passengers). Carrying above the GVW is a safety hazard, especially in braking.
Compact trucks like the Ford Ranger are rated for around 1,500 pounds of cargo, so it's better to split the load into two unless it’s very light dry wood. Half- and three-quarter-ton pickups like the popular Ford F150, Dodge Ram and Chevy Silverado will carry around 2,000 to 3,000 pounds. Many of these pickups will carry a full seasoned cord in one load; check your pickup specifications. Allow for extra weight and maybe extra trips if you intend to haul green wood.