FNR-109
forestry & natural resources
MARKETING AND UTILIZATION 
Top Weight Estimates for Sawlog Size Hardwood Timber
Daniel L. Cassens
Expanded use of wood fiber for traditional uses, as well as the use of wood as a commercial and domestic energy source are indications that the utilization of logging residues and other small diameter or low value timber will increase. Small diameter timber could be removed during timber stand improvement operations. Logging residues could be harvested along with the rest of the tree and, therefore, are likely to be the first material utilized by commercial operations. Logging residues include all of the above ground tree parts, except the stump, left after the sawlogs are removed. Before expanded utilization of small diameter timber and logging residues is realized, some estimate of the weight or volume of available wood is desirable. These estimates could help determine the economic feasibility of removal.
This report will present total tree oven-dry weights for small diameter hard and soft hardwoods, top weight data for sawlog size oak in Indiana, and regional data for oak and other hardwood species. Even on a regional basis, only a limited number of studies have been reported. Therefore, care must be exercised in the application of the data. In all cases, the data were collected on commercially grown forest trees. Open grown trees, or timber with excessively large tops, will give substantially higher yields. Erroneous results can also occur when the data are applied to only one or even small groups of trees.
The top weight data in this publication are given for the oven-dry (105°C or 221°F) condition. Oven-drying removes all of the water from wood. These oven-dry weights can be converted to weights at different moisture contents. For example, firewood cut to length and split to stovewood size will dry to about 15 to 20 percent moisture content in one full summer under ideal conditions. The following formula is applicable for this conversion:
                  M
w =          -----
      D(1 + 100)
where:
W = weight of wood at any moisture content
D = weight of wood oven-dry (see Tables 2-8)
M = wood moisture content (in percent) for which “W” is desired
The green moisture content of some common woods is given in Table 1 (Wood Handbook 1974). Therefore, the weight of wood given can also be calculated by using the formula given above. The heart wood moisture content varies from a low of 46 percent for white ash to a high of 114 percent for sycamore; while the sapwood moisture content ranges from a low of 44 percent for white ash to a high of 137 percent for sweetgum. The sapwood moisture content may be lower or higher than the heartwood depending on the species. However, the sapwood will usually dry faster or at least as fast as the heartwood. Heartwood often contains extractives or other obstructions which inhibit drying.
Table 1 also gives the weight per cubic foot of solid wood in the green and air-dried condition. A standard cord containing 128 cubic feet of wood, bark, and air space is assumed to have 80 cubic feet of wood in it. Therefore, the approximate weight of one cord of wood of any particular species can be calculated.
Table 2 presents the total tree oven-dry weights of several small diameter hard and soft hardwood species sampled at different locations. The hard hardwoods include sugar maple, yellow birch, beech, northern red oak, white ash, and red maple from New York (Monteith 1979); sugar maple from the lake states (Steinhill and Winsauer 1976); and hickory, red and white oaks, red maple, and black cherry from the Appalachian Mountains (Wiant 1977). The soft hardwoods include yellow poplar from the Appalachian Mountains (Wartluft 1978; Clark and Schroeder 1977). Even with the large variation in species and sampling location, relatively small differences exist in the total tree oven-dry weights for any of the above hard hardwoods with a Diameter at Breast Height (DBH) of less than about 14 inches. Therefore, the data for each individual species was combined and is shown in Table 2. Being a soft hardwood, yellow poplar is substantially lighter and thus is shown separately.
Tables 3 and 4 give the weight of wood and bark in all branches and the weight of wood and bark for branches equal to or greater than four inches in diameter by tree DBH and merchantable height for 54 red, white and black oak trees from southern Indiana (Dubois County). The
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