Timber Cruising for Laymen, Part III

Determining tonnage of timber in a tree 

Armed with the Diameter of the tree in question, the height, the species and the category in which the tree falls, we are now ready to relate this to its weight expressed in tons. 

Pulpwood:

Below are volume tables for loblolly, shortleaf, longleaf, and slash pines, expressed in pounds.  Thus a loblolly pine with a usable height of 60′ with a DBH of 9″ should weigh approximately 632 pounds.  Dividing by 2000 yields 0.316 tons.  This table is useful for evaluating pulpwood pines.  This might be for plantation pines or just natural regrowth.

  Loblolly and Shortleaf Pine Weights in Pounds
Diameter (inches at DBH) Total Tree Height (feet)
  20 30 40 50 60 70
 6 83.507 128.816 175.496 223.221 271.794 321.082
 7 115.811 148.983 244.003 310.431 378.001 446.537
 8 152.307 235.619 321.324 408.852 497.861 588.119
 9 193.054 298.827 407.606 518.675 631.603 746.100
10  238.078 368.651 502.910 639.978 779.924 920.595
             
             
  Slash and Longleaf Pine Weights in Pounds
Diameter (inches at DBH) Total Tree Height (feet)
  20 30 40 50 60 70
 6 89.128 137.486 187.308 238.246 290.088 342.693
 7 123.606 159.011 260.426 331.325 403.443 476.593
 8 162.558 251.478 342.952 436.371 531.371 627.704
 9 206.048 318.940 435.041 553.586 674.115 796.318
10  254.103 393.464 536.760 683.054 832.419 982.558
             
    tons = pounds/2000      

 Similar tables are available for hardwood pulp.  Actually you can use the same tables but add a little for the extra density of hardwood pulp.

 

The Hardwood tables below reflect the larger sizes that are readily found in our forests.  Generally the estimates for tree volumes are the same for different species of hardwoods, but if you want to be more exacting you can adjust your figures by applying a conversion factor for the particular species.

 
    Weight of Hardwood Trees in TONS
Height of Tree in Feet
DBH 60 70 80 90 100 110 120
12 0.33 0.53 0.73 0.93      
13 0.48 0.68 0.88 1.08      
14 0.64 0.84 1.04 1.24      
15 0.81 1.01 1.21 1.41 1.61    
16 0.99 1.19 1.39 1.59 1.79 1.99  
17 1.18 1.38 1.58 1.78 1.98 2.18  
18 1.38 1.59 1.79 1.99 2.19 2.39  
19 1.6 1.8 2 2.2 2.4 2.6 2.81
20 1.83 2.03 2.23 2.43 2.63 2.83 3.03
21 2.27 2.47 2.67 2.87 3.07 3.27
22 2.52 2.72 2.92 3.12 3.32 3.52
23 2.78 2.99 3.19 3.39 3.59 3.79
24 3.06 3.26 3.46 3.66 3.86 4.06
25 3.55 3.75 3.95 4.15 4.35
26 3.85 4.05 4.25 4.45 4.65
27 4.16 4.36 4.56 4.76 4.96
28 4.48 4.68 4.88 5.08 5.28
29 4.81 5.01 5.21 5.41 5.61
30 5.36 5.56 5.76 5.96
31 5.71 5.91 6.11 6.32
32 6.08 6.28 6.48 6.68
33 6.46 6.66 6.86 7.06
34 6.85 7.05 7.26 7.46
35 7.26 7.46 7.66 7.86
36 8.07 8.27

 

 

  Adjustment Factors for Hardwoods
Species Factor
  Red Oaks
Southern Red Oak 1.054
    Black Oak 1.033
    Northern Red Oak 1.018
    Cherrybark Oak 1.015
    Nuttall Oak 0.999
    Water Oak 0.996
    Willow Oak 0.963
  White Oaks
Post Oak 1.026
    Overcup Oak 0.997
    White Oak 0.958
  Others
Mockernut Hickory 1.013
    Shagbark Hickory 0.987
    Bitter Pecan 0.966
    Sweetgum 0.974
  
 
Sawtimber tables are not usually as readily available because they tend to use board foot tables.  This is created by the emphasis that these species place on lumber production.  Such timber is usually categorized in board feet.  Board feet are measured either in Scribner of Doyle Board feet.  The differences are are in the assumptions on how the logs will be cut at the mill.  In our area Scribner is generally used for pine sawtimber and Doyle is used for Hardwood sawtimber.  The technique used here is to estimate the volume of the tree in board feet according to its classification as pine or hardwood sawtimber.  These figures can then be converted to tons for evaluation.   Below are timber tables commonly used in our area.  Because of their size we have made them available as Portable Document Files ( pdf ).
The 78 refers to a form factor for trees.  The 78 is typical for our area ( East Central Georgia and West Central South Carolina ).  This is fairly typical throughout the southeast but might have some slight local variance.
From these table it is easy to convert DBH and height into Board feet in either the Scribner Scale for pines or the Doyle Scale for Hardwoods.  To convert to tons you can use the table below:
   
    Average Weight of Pine Pulpwood Cords
         
Species   Green   Air Dried
Longleaf   6080   4984
Slash   5760   4936
Shortleaf   5720   4464
Loblolly   5560   3912
Pond   5320   4120
Spruce   4960   3968
Sand   4400   3936
         
         
Product   Yield   Average Weight
Pine Sawtimber Scribner, 1000 board feet 15000
Hardwood Sawtimber Doyle, 1000 board feet 17500
Pine Pulpwood Standard Cord, 128 cubic feet 5550
Hardwood Pulpwood Standard Cord, 128 cubic feet 5800
This is only an approximation but it should be useful in calculating cruised tonnage of individual trees.
You should now be able to measure a tree in DBH and height.  You should further be able to convert from its type to tonnage.
Coming Soon:  Timber Cruising for Laymen, Part IV
Timber tallies and sampling techniques for a tract of timber land.
Tice Brashear
 

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About Tice Brashear

Tice Brashear is the President of Brashear Realty Corporation. He is a licensed real estate broker and has over 37 years experience in selling land, farms, acreage, commercial and investment properties. He is a past President of the Georgia Association of Realtors and a past President of the Augusta Board of Realtors.
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2 Responses to Timber Cruising for Laymen, Part III

  1. Pingback: Georgia Timber Values | Georgia Country Blog

  2. Dan says:

    Thank you so much. Loved your articles. Distilled, hard to find information available in an easy to read and understand format. Looking forward to more.

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