A chip van in California is carrying 26 green tons or 13 bone dry tons of wood chips (50% moisture content is common for us).  Dry wood is 50% carbon by weight. 


And in the carbon marketing world, everything is expressed as carbon dioxide equivalent.  So for every 1 ton of carbon, there is 3.67 tons of carbon dioxide equivalent simply because of the atomic weights of atoms of Carbon (6) and Oxygen (8).  Often you’ll see CO2 expressed in metric tons.  The conversion from our short ton to metric ton is 1 metric ton = 1.1023 short tons.


Everything I’ve compiled in this paper for you is short tons.


The estimated annual net rate of above ground carbon accumulation in California’s forests varies by species (Winrock, 2004, “Baseline Greenhouse Gas Emissions for Forest, Range, and Agricultural Lands in California, CEC 500-04-069F, p. 18):


·       Douglas Fir:          0.55 tons of Carbon/acre or 2.02 tons of CO2 equivalent

·       Fir-Spruce:            0.49 tons of Carbon/acre or 1.80 tons of CO2 equivalent

·       Other Conifer:       0.78 tons of Carbon/acre or 2.86 tons of CO2 equivalent

·       Redwood:             1.05 tons of Carbon/acre or 3.85 tons of CO2 equivalent


For carbon stored in wood products, our data shows that the bole of the tree constitutes 65% of above ground carbon.  Our mill efficiency is 70%.  Hence, 45% of the net rate of carbon accumulation when harvested ends up in a long-lived wood product.


The remainder of the above ground carbon (bark, tops, limbs, . . .) is chipped and goes into a co-generation biomass powerplant to make electricity. 


In California, the different species shown above make up the following percentages of total forestland acreage:


·       Douglas Fir     - 3.2 percent

·       Fir-Spruce       - 6.3 percent

·       Other Conifer  - 88.6 percent

·       Redwood         - 1.9 percent


Intensively managed private forestlands have an average annual net sequestration rate of at least double that of unmanaged or custodial managed Forest Service forestlands. This calculation includes the storage of carbon in wood products.


We believe there should be 2 renewable energy credits in addition to the carbon sequestration credit:


·       “Substitution” – we know, from Dr. Lippke’s work at Univ. of Washington, that non-renewable building materials (concrete, steel, aluminum, vinyl, . . .) take at least 250% more fossil fuel energy to create than an equivalent wood product (ie a renewable energy credit that we believe should be owned and tradable by the wood product manufacturer).


·       Wood Waste offset – we know that when wood waste is used to generate electricity in a biomass powerplant that for every 1 bone dry ton used for power generation, there is a direct offset to using coal or natural gas to fire a powerplant.  For every 1 bone dry ton of biomass used to generate power, there is a 1-ton net reduction of greenhouse gases compared to a coal or natural gas-fired powerplant (Dr. Gregg Morris, Green Power Institute, 2007).


Custodial or “let-it-grow” management scenarios will show an increasing carbon store over time until the tree reaches an age where insects and/or disease invade.  The tree will eventually become a net “emitter”.  In fire-adapted ecosystems, such as the forestlands of nearly all of California, wildfire may destroy a stand well before its expected life span.  In California, the current rate of wildfire on forestlands is 0.64 percent per year.  Hence, every 156 years, you would expect all forestlands would have burned once.  The Governor’s Climate Action Team predicts that there could be up to a 55% increase in wildfire in California by the end of this century increasing the rate of wildfire on forestlands to 1%/year.  Wildfires in California in 2007 were already near the 1% rate.  That means the forest burns up once every 100 years.  As a result, care must be taken in addressing a “no-harvest” or “let-it-grow” comparison to an intensively managed forest.  Dr. Bruce Lippke has shown that for eastern Washington unmanaged forests with a predicted 1.7% burn rate, the forests are significant net emitters rather than net sinks.


Actively managed forests can lead to a 50-60% reduction in the current level of acreage burned due to wildfire (Finney, Mark A., June, 2000.  “Design of Regular Landscape Fuel Treatment Patterns for Modifying Fire Growth and Behavior”. (Forest Science Journal 47(2) 219-288)).




Critics would have us believe that sequestering more carbon is best achieved by simply allowing growth to continue over time thereby storing more and more carbon in the tree and its roots.  The fact of the matter is that trees grow old and die, eventually giving way to insects, disease and/or wildfire.  As the tree grows old, the growth slows and decomposition occurs, which will overtake growth. The tree will eventually become a net emitter of carbon due to the decomposition of the dead material.

Air quality – Biomass for power generation results in a 96-98 percent reduction in emissions compared to open field burning[1] (see Table 1) .



TABLE 1:  Comparison of Emissions Between Biomass Boilers and Field Burning



Field Burning (lb./ton)

Biomass Boiler (lb./ton)

Percent Reduction for Biomass Boiler

Sulfur Oxides




Nitrogen Oxides




Carbon Monoxide


















The Western Governors Association commissioned a Biomass Taskforce that completed a Report in January 2006.  That report indicates there are at least 11 cents/kilowatt of uncompensated social and environmental benefits associated with using woody biomass to generate electricity:


·       Criteria Pollutants (Lead, Particulate Matter, NO2, SO2, CO & Ozone

            - 4.3 cents/kilowatt

·       Reduction in Greenhouse Gas Emissions (water vapor,

Tropospheric ozone, NOx, CO2, CH4, )                                    - 5.9 cents/kilowatt

·       Avoided Landfill                                                                  - 1.1 cents/kilowatt

·        Timber Stand Improvement                                                  - 0.1 cents/kilowatt



A.                        Biomass Conversion Factors


1 green ton of chips             = 2,000 lbs. (not adjusted for moisture)

1 Bone Dry Ton (BDT) of chips       = 2 green tons (assuming 50% moisture content)

1 Board Foot (BF)                           = Lumber measure equivalent to 12”x 12”x 1”

1 MBF                                            = 1,000 BF

1 green ton                                      = 160 BF of lumber

6 green tons                                    = 1 thousand board feet (MBF)

1 BDT of fuel                                 = approximately 10,000 lbs. of steam

10,000 lbs. of steam                         = 1 megawatt hour (MWH) of electricity

1 Megawatt (MW)                           = 1,000 horsepower

1 MW                                             = power for approximately 750-1,000 homes

1 gigawatt (GW)                              = 1,000 MW



Bone Dry Ton (BDT) – traditional unit of measure for pulp/paper and biomass industry.  One BDT is 2,000 lbs. of biomass at zero percent moisture.  Typically forest biomass collected in the woods is delivered “green” to the end use facility.  If it is at 50 percent moisture content, 2 green tons = 1 BDT.


A 50 MW biomass powerplant will use 1,200 BDT/day; 100 chip vans/day





Actively managed forests provide net sequestration of generally a positive 3.5 to 7 tons of CO2e/acre/year when carbon stored in wood products is included.  When the substitution of wood products for non-renewable building materials is included, the benefit is greatly increased.




The assumptions regarding whether or not to account for mortality associated with insects, disease, and wildfire makes a drastic difference in the difference in the life cycle carbon model.  The graph below makes the oversimplification of ignoring wildfire.  The graph on the following page includes the effects of wildfire.

Here, with consideration of mortality from a 1.7% wildfire frequency rate, the Forest is clearly a substantial net emitter.

Chart showing that Biomass Power Generation provides at least a net 1 ton reduction in greenhouse gas emissions compared to a fossil fuel-fired powerplant: