Materials Characterization Paper 

In Support of the

Proposed Rulemaking – 

Identification of Nonhazardous Secondary Materials That Are Solid Waste

Construction and Demolition Materials – Land Clearing Debris 

March 18, 2010

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1. Definition of Land Clearing Debris 

Land clearing debris is defined as growing stock and other timber sources cut or otherwise 

destroyed in the process of converting forest land to non-forest uses.1 Growing stock that is 

removed in silvicultural operations such as pre-commercial thinning is also included in this 

definition. Land clearing debris is typically in the form of tree tops and branches, trees cut or 

knocked down and left on site, and stumps. In non-forested areas, such as grasslands and desert, 

land clearing debris may include soil, rocks, and shrubs, although fuel is primarily derived from 

previously forested areas. 

 

2. Annual Quantities of Land Clearing Debris Generated and Used 

(1) Sectors that generate Land Clearing Debris: 

• NAICS 561730 Landscaping Services - This industry comprises (1) 

establishments primarily engaged in providing landscape care and maintenance 

services and/or installing trees, shrubs, plants, lawns, or gardens and (2) 

establishments primarily engaged in providing these services along with the 

design of landscape plans and/or the construction (i.e., installation) of walkways, 

retaining walls, decks, fences, ponds, and similar structures (U.S. Census Bureau 

2007). 

• NAICS 11310 - This industry comprises establishments primarily engaged in one 

or more of the following: (1) cutting timber; (2) cutting and transporting timber; 

and (3) producing wood chips in the field (U.S. Census Bureau 2007).. 

• NAICS 236 – This subsector comprises establishments primarily responsible for 

the construction of buildings. The work performed may include new work, 

additions, alterations, or maintenance and repairs. The on-site assembly of precut, 

panelized, and prefabricated buildings and construction of temporary buildings 

are included in this subsector. (U.S. Census Bureau 2007). 

(2) Quantities and Prices of Land Clearing Debris Generated: 

• In 2002, 30 million short tons of land clearing debris were generated in the U.S. 

According to a 2002 USDA Forest Service Study, 10 percent was considered to 

be unusable because of size, location, or other reasons. Based on this assumption, 

 1 This is distinct from forest derived biomass, which is extracted from logging operations on areas that will 

remain forest land. 
Construction and Demolition Materials – Land Clearing Debris 

27 million short tons of land clearing debris were available for recovery in 2002 

(McKeever 2002, p. 3-4). 

• Paper mills sign one, two or three year contracts with supply companies for land 

clearing debris used as fuel. The price per ton depends significantly on the 

distance over which the material must be transported. One source identified for 

the development of this document suggests that ground wood that meets mill 

specifications commands a market price ranging from $15 to $20 per ton 

(Goldstein 2006, p. 29). 

• A developing market for biomass is exportation to Europe, where biomass 

demand has increased due to cap-and-trade policies and other efforts to reduce 

fossil fuel use and emissions (Yepsen 2008, p. 51). 

(3) Trends in generation of Land Clearing Debris: 

• Information was not readily available to gauge the trend in the generation of land 

clearing debris. 

3. Uses of Land Clearing Debris 

(1) Fuel uses of Land Clearing Debris: 

• Land clearing debris is commonly used as a fuel in industrial boilers. In general, 

this material can be combusted for energy recovery if the processing capacity and 

markets for the fuel exist. Furthermore the thermal value of this material varies 

depending on its moisture content. Wood with a moisture content of 50 percent 

generally has a heating value between 9 and 10 million btu/ton (4,500 to 4,980 

btu/lb) (EPA 2003, EIA 2008c). The heating value for dry (0 percent moisture) 

woody materials2

 is typically between 15.5 and 16.4 million Btu/ton (7,750 to 

8,200 btu/lb) (Wright et al. 2006). If oven dried, however, wood may produce 

approximately 9,000 Btu/lb when burned, and can also be converted to liquid or 

gaseous fuel. Mixed wood debris with some green wood has a Btu value typically 

near 7,300 Btu/lb, and debris with higher percentages of green wood can have 

lower Btu values, though land clearing debris is typically dried as part of its 

processing. In addition, it is possible to produce different forms of solid fuel from 

wood debris, such as charcoal (SWANA 2002, p. 2, 24, 30, Goldstein 2006, p. 

29). 

• The combustor survey database developed by EPA for the 2009 proposal of the 

Commercial and Industrial Solid Waste Incinerator (CISWI) standards and the 

Industrial Boilers Maximum Achievable Control Technology (MACT) standards 

indicates that the sources surveyed for these rules annually combust 

approximately 3.3 million tons of secondary wood material that may be 

construction and demolition disaster debris (EPA 2009).3,4

 2

 Also called the gross or higher heating value. 

3

 Although we report wood quantities from the combustion database as tonnages, the database includes 

material quantities expressed in terms of heating values (Btu). To express this information as a tonnage, we 

assumed that wood has a heating value of 7,975 Btu per pound, which is the midpoint of the 7,750 to 8,200 Btu/lb 

range for wood reported by Wright (Wright 2006). 

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Construction and Demolition Materials – Land Clearing Debris 

 

(2) Non-combustion uses of Land Clearing Debris:

• Non-combustion beneficial use applications for land clearing debris include 

shredding for mulch and other land applications. Land clearing debris can also be 

composted. 

(3) Quantities of Land Clearing Debris Landfilled: 

• Information was not readily available to gauge the amount of land clearing debris 

that is disposed in landfills. 

(4) Quantities of Land Clearing Debris Stockpiled/Stored:

• The data sources consulted in the development of this document did not suggest 

that large quantities of land clearing debris are stored or stockpiled. 

4. Management and Combustion processes for Land Clearing Debris 

(1) Types of units using Land Clearing Debris:

• For combustion/fuel applications, land clearing debris is primarily used by woodfired industrial boilers and burners. Mulch is sold to landscaping companies, 

suppliers, or retailers for use by residential and commercial customers. 

• Public comments submitted on behalf of the American Forest and Paper 

Association indicate that forest products boilers are specifically designed to 

handle biomass, particularly the lower Btu value material such as biomass with 

higher moisture content (Hunt 2009). 

(2) Sourcing of Land Clearing Debris:

• Some companies that process land clearing debris use wood derived from their 

own land. Other processors typically receive land clearing debris from land 

clearing companies and municipalities that collect yard trimmings. Processing 

companies then provide wood chips to mills with whom they have contracted 

(Goldstein 2006, p. 29). 

(3) Processing of Land Clearing Debris: 

• At processing facilities, land clearing debris goes through a multi-step process to 

produce marketable wood fuel. After the debris arrives at the processing facility, 

it is inspected for contaminants, and an excavator is used to remove any 

contaminants identified. A bulldozer with a rake then shakes the material to 

remove any soil that is attached to the debris. Following this step, the woody 

products are staged in stockpiles to dry prior to grinding. Processors then grind 

the debris so that it can easily be fed into an industrial boiler. The ground wood 

generally needs to be 2-inch minus in size and scope for most mills. Some 

 

4

 The categories of wood material in the combustion database that may contain C&D land clearing debris 

include (1) unadulterated wood and (2) unadulterated lumber. Note that these categories could include building 

debris, disaster debris, or biomass (as defined in the three biomass materials characterization papers) rather than land 

clearing debris. 

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Construction and Demolition Materials – Land Clearing Debris 

processing facilities achieve the 2-inch minus size in one grind, whereas other 

processes will do double grinding (Goldstein 2006, p. 29). 

After land clearing debris is processed, the mills that purchase wood fuel derived 

from this material will often conduct a test burn to evaluate the moisture content 

of the fuel. Mills prefer wood fuel with a low moisture content because it has a 

higher Btu value per pound (Goldstein 2006, p. 29). 

(4) State status of Land Clearing Debris use as fuel: 

• According to state responses to a 2006 survey by the Association of State and 

Territorial Solid Waste Management Officials (ASTSWMO), two states—New 

York and North Carolina—have approved the use of recovered wood materials as 

a fuel source on at least one occasion, but it is unclear whether these approvals 

apply to wood debris from land clearing or the beneficial use of finished wood 

product. In both states, the beneficial use of recovered wood materials as a fuel 

does not appear to have pre-approved status (ASTSWMO 2007, p.B-42). 

5. Land Clearing Debris Composition and Impacts 

(1) Composition of Land Clearing Debris:

• By definition, land-clearing debris is made up of cleared vegetation, and may 

include rocks and soil. 

(2) Impacts of Land Clearing Debris use:

• Cost Impacts: The net cost impacts associated with the beneficial use of land 

clearing debris as a fuel depends on the avoided input or fuel costs for facilities 

that use these materials and the cost of beneficial use itself. Information on the 

processing costs for land clearing debris is not readily available, but the fuel 

savings associated with using this material as a substitute for conventional fuels 

could be as follows, depending on the fuel replaced:5 

Natural Gas (Industrial): $7.35 / MMBtu (EIA 2008a, Table 20) 

No. 2 Distillate (Industrial): $16.80 / MMBtu (EIA 2008b, Table 36) 

Residual Fuel Oil Average: $9.19 / MMBtu (EIA 2008b, Table 38) 

Coal – Average Delivered Price in 2006: $2.23 / MMBtu (EIA 2007, Table ES1) 

• Emissions Impacts of Combustion: Exhibit 1 compares the emission factors for 

wood with the corresponding values for conventional fuels that land clearing 

debris may displace. The estimates in the exhibit suggest that the combustion of 

wood results in higher PM emissions than natural gas or distillate oil, but lower 

PM emissions than coal or residual oil systems. The data in Exhibit 1 also suggest 

that wood results in lower SO2 emissions than most conventional fuels. The 

estimated NOx emissions associated with wood combustion are similar to those 

 5

 To express these values as dollars per MMBtu, the following thermal conversion factors were used: 1,031 

Btu per 1,000 cubic foot of natural gas, 138,690 Btu per gallon of Number 2 distillate, 149,690 Btu per gallon of 

residual fuel oil, and 22,473,000 Btu per short ton of coal (EIA 2005, Tables A1, A4, and A5). 

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Construction and Demolition Materials – Land Clearing Debris 

5

 

associated with distillate and lower than the NOx emissions for other conventional 

fuels.6

 

Exhibit 1 also includes greenhouse gas emission factors associated with the 

combustion of wood. It is unclear, however, whether the combustion of wood 

land clearing debris would lead to increased greenhouse gas emissions. 

Vegetative land clearing debris, by definition, has already been removed from the 

ground and therefore has initiated decay. Combustion of this material merely 

accelerates the release of the stored carbon into the atmosphere. 

• Lifecycle Emissions Impacts: Use of land clearing debris as a replacement for 

traditional primary fuels may eliminate the environmental impacts associated with 

extraction and processing of traditional fuels. In addition to the emissions 

impacts of combustion described above, Exhibit 1 lists the quantities of the total 

cradle-to-gate emissions for these fuels based on typical processes in the United 

States in the late 1990s, with wood scrap combustion presented as a proxy for 

land clearing debris. Note that there may be impacts associated with the 

processing of land clearing debris into useable fuel that are not accounted for in 

the values presented in Exhibit 1. In addition, there may be alternative uses (e.g., 

composting) that are environmentally preferable to combustion. 

6

 We note that the emission factors for wood presented in Exhibit 1 represent averages for wood-burning 

boilers. To the extent that these data reflect the combustion of finished wood product (e.g., C&D wood debris), they 

may not be representative emissions from the combustion of land clearing debris. 
Construction and Demolition Materia

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Exhibit 1: Comparative Impacts of Wood Combustion versus Alternative Primary Fuels 

Wood Coal Distillate Fuel Oil Residual Fuel Oil 

Combustion Combustion 

Combustion 

plus 

Upstream Combustion 

Combustion 

plus 

Upstream Combustion 

Combustion 

plus 

Upstream Co

Pollutant 

----------------------------------------- lb./MMBtu ------------------------------------

Criteria Pollutants PM2.5 - - - - - - - PM10 0.019 0.054 0.054 0.011 0.011 0.093 0.093 PM, unspecified - - 0.246 - 0.012 - 0.012 NOx 0.167 0.482 0.504 0.173 0.234 0.367 0.428 VOCs - 0.006 0.014 0.001 0.363 0.002 0.367 SOx 0.008 1.446 1.469 0.209 0.394 1.593 1.781 CO 1.511 0.068 0.085 0.036 0.082 0.033 0.079 Pb 1.33x10-4 8.93x10-6 9.19x10-6 4.60x10-6 5.61x10-6 5.80x10-5 5.90x10-5 Hg - 2.05x10-6 2.14x10-6 1.58x10-6 1.77x10-6 8.67x10-6 8.85x10-6 Greenhouse GasesCO2 233.3 210.7 214.7 161.2 180.1 173.3 192.5 CH4 - 0.007 0.458 3.74x10-4 0.03 0.007 0.036 N2O - 0.003 0.003 - 2.01x10-5 - 2.07x10-5 MTCO2E/MMBtu 0.106 0.096 0.102 0.073 0.082 0.079 0.088 Source:Franklin Associates 1998. Note:

“-” signifies data not available; may equal zero. The emission information presented in this table is derived from Life Cycle Inventory (LCI) data, as compiled by Franklin Associates. quantifies resource inputs, energy requirements, and releases to the air, water, and land for each step in the manufacture of a product or extraction of the raw materials to ultimate disposal. The LCI can be used to identify those system components or life cycle steps that arto environmental burdens such as energy use, solid waste, and atmospheric and waterborne emissions. Uncertainty in an LCI is due to input uncertainties and data variability. There are several life cycle inventory databases available in the U.S. and Europe. For this paper, we applied the most readily available 

most consistent with the materials and uses examined. These LCI data rely on system boundaries as defined by Franklin Associates, as 

documentation for this database, available at: http://www.pre.nl/download/manuals/DatabaseManualFranklinUS98.pdf. 
Construction and Demolition Materials – Land Clearing Debris 

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