The FHWA’s Carbon Sequestration Pilot Project estimated the amount of unpaved National Highway System right-of-way at five million acres of land in its May 2010 final report.  Right-of-way vegetation management is a major responsibility of state departments of transportation (DOTs). Traditionally, roadside vegetation has been managed for a variety of purposes important to the public, especially safety, but also roadway integrity, habitat, native plant restoration, invasive plant reduction, aesthetics, water quality, and erosion control. Increasingly however, the DOTs are now being asked to also manage their roadsides to address greenhouse gas (GHG) emissions.  Carbon sequestration and biomass production are the two most likely ways that DOTs would approach this issue—through planting and management of potential biofuel, or through long-term management of vegetation for maximum carbon storage. Biological carbon sequestration is one strategy for using vegetation to reduce carbon dioxide (CO₂) in the atmosphere. In 2008, the Federal Highway Administration (FHWA), Office of Natural and Human Environment (HEPN) and Office of Project Development and Environmental Review (HEPE) created the Carbon Sequestration Pilot Project (CSPP) in an effort to define a process or program that could demonstrate the value of sequestering or capturing carbon from the highway right-of-way through design and modified maintenance and management practices.   A final report on the CSPP was issued by the FHWA and the John A. Volpe National Transportation Systems Center in May of 2010.Carbon sequestration is the capture and storage of CO₂ from the atmosphere by plants as they perform photosynthesis. Though plants also release CO₂ back to the atmosphere when they die and decay, land management practices can result in the long-term sequestration of significant amounts of carbon in the soil and plant matter. Techniques that might improve soil carbon sequestration include fertilizing, using native species, sowing legumes, avoiding overgrazing (or over mowing), and minimizing soil disturbance. In addition to ecological benefits, carbon sequestration can have meaningful economic impacts. Markets for trading "carbon credits," or offsets, are in the early stages of development. Existing offset protocols that might be analyzed for applicability to rights-of-way include those developed or under development for domestic programs including the EPA Climate Leaders Program, 1605(b) DOE registry, Climate Action Reserve, Regional Greenhouse Gas Initiative (RGGI), and Chicago Climate Exchange (CCX); as well as international programs including the Voluntary Carbon Standard (VCS) Agriculture, Forestry, and Other Land Use (AFOLU) Methodologies.  Determining carbon credits will require use of a qualifying accounting methodology that address various established GHG protocol steps and existing guidelines. Offset protocols provide detailed guidance to: (1) determine if the project meets all eligibility criteria, including regulatory screens, additionality assessments, and other criteria including project duration and location; (2) define the project boundary (e.g., physical location, GHG accounting and temporal boundaries); (3) select and quantify a baseline, based on existing quantification methodologies and calculation tools; (4) quantify and monitor project GHG emissions and calculate GHG reductions; and (5) meet other protocol requirements such as permanence and leakage measures. Other elements of the protocol may also include guidelines for project start dates and duration, and verification and reporting requirements. Biomass production on rights-of-way would likely need to consider the cost-effectiveness of planting, managing, harvesting, and transporting the biomass to production facilities. Suitable biomass crops may also be used for forage production, game cover, fiber, timber production, electricity or heat production, and other uses.If the challenge is to be met, DOTs need information on regionally appropriate native and non-invasive plants appropriate for roadside use that describes carbon sequestration capabilities and biomass production. While numerous models and protocols exist on carbon sequestration in trees and forests (Center for Urban Forest Research, 2009), protocols for biomass generation or carbon sequestration on highway rights-of-way are lacking.

 

 

 

The objective of this research is to produce a guidebook identifying methods and protocols for DOTs and other transportation agencies to maximize production of marketable biomass products and saleable carbon sequestration credits within their rights-of-way, while considering traditional vegetation management objectives.

 

Accomplishment of the project objective will require at least the following tasks.

 

 

 

(1). Conduct a literature search of published research on vegetation management for marketable biomass production and carbon sequestration credits potentially applicable to transportation rights-of-way.(2). Conduct a search of existing and proposed programs or specific cases of vegetation management for marketable biomass production and carbon sequestration credits potentially applicable to transportation rights-of-way. (3). Identify established carbon sequestration offset protocols for ecosystems (e.g., grassland, forest) and management techniques that are likely to apply to rights-of-way, provide GHG benefits, and potentially qualify for carbon credits. (4). Identify established methods to produce marketable biomass applicable to the rights-of-way.(5). Synthesize the results of Tasks 1 through 4 and develop a method of plant species selection and ecosystem management techniques applicable to individual state DOTs to maximize (a) the carbon sequestration rate and/or (b) marketable biomass quantity. (6). Prepare a detailed outline of the proposed guidebook that contains methods and protocols related to the the previous tasks. (7). Prepare an interim report providing the results of Tasks 1 through 6. (8). Prepare the guidebook containing methods and protocols detailed in the interim report as discussed with the NCHRP project panel. In addition, prepare a final report documenting the research performed in support of the guidebook.