• thinnings (both understory and overstory),– Secondary» slash (residual waste from stand management activities, typically piled and burned),» residuals from wood processing (slabwood, mill ends, bark , chips, sawdust)» urban forestry trimmings and waste– Tertiary› pulp slurryMunicipal Solid Waste– Secondary» combustible solid waste» compostable solid waste» residuals from energy production (such as expressed algae)» yard waste» bio-based materials from natural disasters–Tertiary› carcasses› human wasteThe Scope of Sustainability GuidelinesSustainability guidelines need to cover the biomass sectors noted above, particularly the primary sources, butalso must consider a plethora of related issues. Some are overarching, others sector-specific, still others onlyregionally significant.Sustainability like most challenges must look upstream and downstream, addressing supply and demand, aswell the factors that influence them. Clearly, sustainability guidelines must address at a least two levels abovethe point of utilization. For instance, use of biomass at a biochar production facility must not only be fully awareof the conditions of the local supply of biomass, but also the regional impacts and the ecoregions impacts of itsremoval and use. Regional and national policies will directly affect that plant’s operations. Likewise, regionaland national opinion and perceptions on biomass use will also play into informing those policies.In turn, national policies need to take into consideration international policies and ensure compatibility withagreements, trade regulations and socially and environmentally acceptable practices as defined in instrumentssuch as those developed by the International Union for Conservation of Nature, the United Nations World Commissionon Sustainable Development and the Forestry Stewardship Council. Specific guidelines and recommendationsfrom <strong>report</strong>s by collaborative efforts of these organizations and others are discussed below.Regulatory Framework – Sustainability guidelines are strongest and more readily adhered to and enforced ifthey are mandatory. In lieu of a framework for codifying mandatory practices, voluntary compliance to guidelinescan be successful if peer-pressure, watch-dog groups and market advantages combine to create incentivesfor sustainable practices.Compliance – Guidelines, whether mandatory or voluntary, need to be concrete and measurable. Conceptualguidelines may be of help in creating greater understanding of system interrelationships but knowledge doesnot necessarily lead to positive and sustainable practices when economic imperatives are deemed of greaterimportance. Thus, there exists a preference for a more rigorous regulatory and compliance structure for biomassin general and biochar in particular.Metrics – Performance or lack thereof, needs to have metrics for confirming that practices are within acceptabletolerances for ensuring the sustainability of biomass feedstocks. This becomes increasingly difficult in situa-42U.S.-Focused <strong>Biochar</strong> Report:Assessment of <strong>Biochar</strong>’s Benefits for the United States of America
tions where the baseline measurements can only be estimated. Agreement on data configuration, data sourcesand assumptions in quantification are necessary.Scope – Sustainability guidelines/regulations need to be valid for a wide range of biomass types, particularlyprimary sources. Assessments cannot stop at simply the above-ground supplies but also consider the impactsto soil and hydrologic systems from repeated short-cycle harvesting of surface biomass.Life Cycle Assessment – The entire life-cycle of individual types of biomass feedstocks must be taken into consideration.Indigenous, local biomass typically will have a smaller carbon footprint than biomass imported fromhundreds of miles away. But the entire supply chain must be examined to ensure that the pitfalls of previous effortssuch as biofuels using corn-to-ethanol, do not reoccur. (In the case of corn-to-ethanol, only after substantialinvestments were made in infrastructure and increased corn production, was it realized that the energy return onenergy invested (EROEI) fell far short of positive, besides causing serious price disruption in corn-based foodsystems). The goal in biomass to energy production is to reduce the overall input of fossil fuel energy and inturn the level of greenhouse gas emissions. Renewable energy systems requiring greater fossil fuel inputs thanare offset defeat their purpose.Hydrologic Systems – Given that only 3% of water on the surface of the earth is potable and that 6 billion peopleand all terrestrial ecosystems are dependent on it for survival and that climate change is disrupting hydrologiccycles on a massive scale, water must be a key consideration in biomass production and use schemes. Similar tothe concept of EROEI, an analysis of ‘energy return on water invested’ must be part of the life-cycle assessment.Biomass physically serves important functions for the hydrologic cycle on a micro-scale as it protects the soilfrom erosion and creates protected microclimates for plant reproduction by providing shade and water retention.(See nutrient cycling below)Social Equity – Land use issues are critical to the sustainability of biomass and sustainability of human culturesand practices. Conversion of productive farmland from food crops to biomass production is an anathema tosocial justice and battling hunger. Likewise conversion of native forest ecosystems and their many resources,upon which most cultures depend, cannot be converted to biomass plantations without causing significant socialimpacts, including severe health and psychological damage.In developed countries, many people are fortunate to live in woodland or agricultural settings that are highlyprized for their scenic views and naturalness. There is growing resistance to biomass removal, as it is perceivedto remove key elements that make living in such setting so desirable psychologically and valuable from an economicstandpoint.Biodiversity – As noted under social equity, substitution of plantations for native forest and grasslands causessevere consequences for humans. From an ecological perspective, the impacts to wildlife, biodiversity and complexecosystems from land development are equal or greater, however they may be less visible to humans in theshort-term. Essentially, land conversion from native ecosystems removes primary production capacity, oftenirreversibly in the context of human life spans.Biomass also serves as habitat for important microbes, insects and small amphibians and mammals. Biomass inwaterways provides critical fish habitat.Nutrient Cycling – Biomass, particularly decaying materials, recycles nutrients back into soil while providinghabitat, shelter, water retention and erosion protection.Land Use – Biofuels can be substituted for fossil energy only if the large-scale production of biofuels is biophysicallyfeasible, meaning the production is not constrained by the availability of land and fresh water sources forenergy crop production. 8 Humans are already developing the earth’s surface at an alarming rate. In America,two acres of farmland per minute per day are being converted to development. In a five-year period in the mid-8 Giampietro, M., Ulgiati, S., and Pimentel, D., “Feasibility of Large-Scale Biofuel Production,” BioScience, 47(9), 587-600. 1997<strong>Biochar</strong> sustainability in: <strong>Biochar</strong> and Sustainable Practices43