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Pine Timber Volume-to-Weight Conversions

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Publication Number: P2244
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Can you answer the following questions? How many tons does one MBF pine sawtimber weigh? One cord of chip-n-saw? One cord of pine pulpwood? How can a bid per ton be compared to a bid per MBF? Per ton versus per cord? If you don’t know the answers, read on!

Converting pine timber volume to tons (or tons to volume) can be useful for tax record keeping, growth monitoring, and marketing. Measurement standards for pine timber have changed over the last couple of decades. Inventories of standing timber in the past were kept in units of volume (cords and MBF). Today, we measure standing timber by weight. You need conversions to keep consistent records and estimate timber growth. Conversions can be particularly helpful when determining timber basis and deducting timber depletion from income.

High-production pine sawmills have changed to weight scaling and buy timber by the ton (2,000 pounds). Mills producing fuel, chips, pulp, or paper are also measuring timber only by weight. However, high-grade pine lumber and specialty mills often still measure volume using the Doyle Log Rule and pay per MBF (1,000 board feet).

This is important because state law requires mills in Mississippi to buy timber using a consistent measurement (Mississippi Statute 75-27-113). Mills that weigh timber logs must buy by weight. Mills that stick-scale timber volume must use the same unit of volume. This publication helps you know how to compare a bid in $/cord or $/MBF to another bid in $/ton.

The volume-to-ton conversions presented are “ballpark” figures close enough for most landowners’ needs. Procurement experts in the forest industry checked the numbers and agreed they are close to theirs. The conversions presented are useful statewide for loblolly, shortleaf, longleaf, and slash pine. Do not use these conversions for spruce pine, or for damaged, beetle infested, or dead timber.

Use conversions only as estimates and guidelines. The weight of wood is determined by moisture content and specific gravity. These vary from tree to tree, making the exact volume-to-ton conversion for your timber different.

Volume-to-Ton Conversions

For conversion purposes, pine timber is divided into three product types: pulpwood, chip-n-saw, and sawtimber (Table 1). Pines with DBH (diameter at breast height) ranging from 6 up to 26 inches can qualify for pulpwood. Chip-n-saw is a medium-valued timber product that yields two-by-fours and chips. Straight, clear stems with DBH from 10 to 14 inches can qualify for chip-n-saw. Highly valued sawtimber ranges from 10 to 30 inches DBH. Larger trees go for specialty products and plywood. Remember, these merchantability limits are highly subject to mill specifications and may differ in your procurement zone.

Longwood (more than 8 feet in length). Pulpwood and chip-n-saw are commonly delivered tree-length in today’s markets. The weight of a cord of these product classes varies by species. Loblolly and shortleaf pines average 2.6 tons per cord. Longleaf and slash pines have a higher specific gravity, making their timber heavier. Longleaf and slash pine average 2.78 tons per cord.

Sawtimber. The Doyle Log Rule commonly is used to estimate volume of lumber in standing trees. Doyle was the only legal measure in Mississippi until 1996, even though it is not accurate. The Doyle Rule greatly underestimates lumber volume in smaller DBH trees (10–16 inches) and overestimates volume in very large trees (30+ inches). To account for Doyle rule inaccuracies, volume-to-ton conversions are presented by two-inch DBH classes (Table 1). Weight can vary from a high of 14 tons/MBF for 10-inch DBH timber down to 4.4 tons/MBF for 36-inch timber. If you know both sawtimber average DBH and merchantable height, you can use Table 2 for a more accurate conversion.

Table 1A. Volume to ton conversions1 for pulpwood2 and chip-n-saw2 in Mississippi. The weight of wood can vary from tree to tree, so use these conversions as estimates and guidelines only.

Product

Tons per cord

loblolly and shortleaf

2.6

longleaf and slash

2.78

Table 1B. Volume to ton conversions1 for sawtimber2 (when only DBH is known) in Mississippi. The weight of wood can vary from tree to tree, so use these conversions as estimates and guidelines only.

Average DBH3

Tons per MBF

10

14.0

12

9.8

14

8.5

16

7.7

18

7.2

20

6.7

22

6.3

24

5.9

26

5.5

28

5.2

30

5.0

32

4.8

34

4.6

36

4.4

11 ton = 2,000 pounds; 1 cord = 128 cubic feet stacked wood; 1 MBF = 1,000 board feet, Doyle Log Scale. Sawtimber conversions adapted from unpublished research by the late James McCreight, consulting forester, Busy Corner, MS, and Lee, G.S., R.C. Parker. 2003. Standing tree weight and volume tables for natural loblolly pine at the first delivery point. Forest and Wildlife Research Center, Bulletin FO 222, Mississippi State University. 14 pp.

2Pulpwood is a timber product used to create pulp fluff for making paper products. Chip-n-saw is a timber product that yields two-by-fours and chips. Sawtimber is a log large enough to saw into lumber, usually at least 16 feet in length.

3Average DBH = average diameter at breast height (4.5 feet above ground level) in inches.

Table 2. Volume to ton conversions for pine sawtimber when you know both diameter at breast height (DBH) and merchantable height to an 8-inch tip. The weight of wood can vary from tree to tree, so use these conversions as estimates and guidelines only.

 

Merchantable height in number of 16-foot logs

DBH inches

1

1.5

2

2.5

3

3.5

4

4.5

5

 

Tons per MBF Doyle1

12

10.9

9.8

9.3

8.9

8.5

8.2

7.9

7.7

7.6

14

10.4

9.5

9.0

8.5

8.2

7.9

7.6

7.4

7.3

16

9.9

9.0

8.5

8.1

7.7

7.5

7.2

7.1

6.9

18

9.4

8.6

8.0

7.6

7.3

7.0

6.8

6.7

6.5

20

8.9

8.0

7.5

7.2

6.9

6.6

6.4

6.3

6.1

22

8.4

7.6

7.1

6.8

6.5

6.3

6.1

5.9

5.8

24

7.9

7.2

6.8

6.4

6.2

5.9

5.8

5.6

5.5

26

7.5

6.8

6.4

6.1

5.8

5.6

5.5

5.3

5.2

28

7.1

6.5

6.1

5.8

5.6

5.4

5.2

5.1

5.0

30

6.8

6.2

5.8

5.5

5.3

5.1

5.0

4.8

4.7

11 ton = 2,000 pounds; 1 MBF Doyle = 1,000 board feet, Doyle Log Scale. Adapted from Lee, G.S., R.C. Parker. 2003. Standing tree weight and volume tables for natural loblolly pine at the first delivery point. Forest and Wildlife Research Center, Bulletin FO 222, Mississippi State University. 14 pp.

Use Conversions

One way to convert a timber inventory to weight is to multiply volume by the appropriate tons/volume (Table 1). Example 1 shows how to convert an inventory in cords and MBF to tons. Determine the species you are growing and the average sawtimber DBH to find appropriate conversions in Table 1.

Example 1. An inventory was taken of a loblolly pine stand with sawtimber averaging 16 inches DBH. The volume estimate was 100 MBF Doyle pine sawtimber, 50 cords chip-n-saw, and 120 cords of pulpwood. How many tons does this pine timber weigh?

Step 1. Find the appropriate conversions in Table 1.

  • sawtimber, 16 inches DBH, 7.7 tons/MBF
  • chip-n-saw, loblolly, 2.6 tons/cord
  • pulpwood, loblolly, 2.6 tons/cord

Step 2. Convert to tons.

  • Sawtimber
    • 100 MBF Doyle x 7.7 tons/MBF = 770 tons
  • Chip-n-saw
    • 50 cords x 2.6 tons/cord = 130 tons
  • Pulpwood
    • 120 cords x 2.6 tons/cord = 312 tons
  • Total weight (add weights of sawtimber, chip-n-saw, and pulpwood): 1,212 tons

Conversions can also help you evaluate timber bids in your most familiar unit. Some timber owners are still more comfortable knowing the $/cord or $/MBF bid price. To estimate these from a $/ton bid, multiply each bid by tons/volume, as in Example 2.

Example 2. A landowner is offered $20/ton for pine sawtimber in three different stands. The first stand averages 10 inches DBH, the second averages 20 inches, and the third averages 30 inches. What are the equivalent $/MBF bids for these stands?

Step 1. Find the appropriate conversion in Table 1.

  • sawtimber
    • 10 inches DBH, 14.0 tons/MBF
    • 20 inches DBH, 6.7 tons/MBF
    • 30 inches DBH, 5.0 tons/MBF

Step 2. Compare bids on $/MBF basis.

  • Stand 1 (10 inches)
    • $20/ton x 14.0 tons/MBF = $280/MBF
  • Stand 2 (20 inches)
    • $20/ton x 6.7 tons/MBF = $134/MBF
  • Stand 3 (30 inches)
    • $20/ton x 5.0 tons/MBF = $100/MBF

Selling sawtimber by the ton is tricky, with the timber owner often losing out considering lumber that cuts out in larger logs. In Example 2, look closely at the effect tree DBH has on the equivalent price per MBF. Large diameter sawtimber should receive more per ton than smaller timber.

Example 3 shows how to estimate a $/ton bid price by dividing the $/cord or $/MBF bid by the tons/volume conversion.

Example 3. A timber buyer offers a landowner $200/MBF for longleaf sawtimber averaging 12 inches DBH and $30/cord for pulpwood. What are the equivalent $/ton bids?

Step 1. Find the appropriate conversion in Table 1.

  • sawtimber, 12 inches DBH, 9.8 tons/MBF
  • pulpwood, longleaf, 2.78 tons/cord

Step 2. Convert bids to $ per ton.

  • Sawtimber bid
    • $/MBF bid ÷ tons/MBF = $200/MBF ÷ 9.8 tons/MBF = $20.41/ton
  • Pulpwood bid
    • $/cord bid ÷ tons/cord = $30/cord ÷ 2.78 tons/cord = $10.79/ton

Example 4 is for pay-as-cut timber sales. You can use conversions to compare two different bids, one based on volume and the other tons. However, before deciding which bid to accept, find out if mill standards are equal. Some mills that pay a lower $/ton price also harvest a longer merchantable length (more weight/tree), bringing you more dollars.

Example 4. A landowner receives two bids for pine sawtimber averaging 14 inches DBH. The first bid is $20/ton and the second $230/MBF. Which is the higher bid?

Step 1. Find the appropriate conversion in Table 1.

  • sawtimber, 14 inches DBH, 8.5 tons/MBF

Step 2. Compare bids on a $/ton basis.

  • Bid 1: $20.00/ton
  • Bid 2: $bid/MBF ÷ tons/MBF = $230/MBF ÷ 8.5 tons/MBF = $27.06/ton
  • The second bid is higher by $7.06/ton.

Summary

Volume-to-ton conversions may not be exact, but they can be very useful. You can use these conversions to update timber inventories and keep timber bids in familiar units.

Pulpwood conversion varies by species, with longleaf and slash timber heavier than loblolly and shortleaf pine. You need average DBH to find an appropriate conversion for sawtimber. A better sawtimber conversion is possible if you also know average merchantable height.


Publication 2244 (POD-11-19)

Revised by Brady Self, PhD, Associate Extension Professor, Forestry, from an earlier version by Stephen Dicke, PhD, and Robert Parker, PhD, Professors Emeriti.

Copyright 2019 by Mississippi State University. All rights reserved. This publication may be copied and distributed without alteration for nonprofit educational purposes provided that credit is given to the Mississippi State University Extension Service.

Produced by Agricultural Communications.

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Extension Service of Mississippi State University, cooperating with U.S. Department of Agriculture. Published in furtherance of Acts of Congress, May 8 and June 30, 1914. GARY B. JACKSON, Director

Department: Forestry

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