Environmental sustainability of cellulosic energy cropping systems

Authors: Lowrance, Robert; Davis, Adam

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 12/15/2003
Publication Date: 4/10/2014
Citation: Lowrance, R., Davis, A. 2014. Environmental sustainability of cellulosic energy cropping systems. In: Karlen, D.L., Editor. Cellulosic Energy Cropping Systems. John Wiley & Sons, Ltd, Chichester, UK. 15p. doi: 10.1002/9781118676332.

Interpretive Summary: This chapter evaluates what is known about the environmental sustainability of cellulosic bioenergy crop production for the types of production systems discussed elsewhere in the book. The environmental sustainability of feedstock production systems will depend on several factors including their effects on greenhouse gas (GHG) emissions , soil and water resources, wildlife, and whether the feedstock is a potentially invasive species or can harbour them. These direct effects are generally determined based on direct land use change from annual crops, managed perennial vegetation (e.g., perennial pastures, industrial or non-industrial forest plantations), or other types of perennial vegetation (i.e., natural forest or grassland). Although conversion of natural grasslands or forests to bioenergy crops may occur, both USDA regulations concerning conversion of natural grasslands and stated policies for biomass sources are meant to avoid conversion of native vegetation. Most of the direct environmental effects of cellulosic biomass production will come from existing agricultural land (pasture and row crop), existing forest plantations, or previously harvested forest land. Direct land use effects are based on our understanding of the changes in field, landscape, and watershed attributes when dedicated feedstock crops replace other land uses or covers. Direct effects (all of which can be either positive or negative) include GHGs; soil quality (including but not limited to soil carbon); water quantity and quality; invasive species; and wildlife habitat. Some of these factors can lead to direct effects on adjacent ecosystems and some can lead to larger effects at the watershed or landscape scale. The effects will also be dependent on where bioenergy crops are produced. For instance, there may be net environmental benefits (especially GHG and soil/water benefits) from conversion of cropland to warm season grasses (WSG) or to short rotation woody crops (SRWC) but for conversion from forest, managed for saw timber production, to biomass there may not be any net benefits. The scale of benefits also depends on the land converted with the general idea being that the less productive and more marginal the land, the greater the benefit from conversion to perennial cellulosic biomass crops.

Technical Abstract: The environmental sustainability of bioenergy production depends on both direct and indirect effects of the production systems to produce bioenergy feedstocks. This chapter evaluates what is known about the environmental sustainability of cellulosic bioenergy crop production for the types of production systems discussed elsewhere in the book. The environmental sustainability of feedstock production systems will depend on several factors including their effects on greenhouse gas (GHG) emissions (CO2, N2O, and CH4), water resources, soil quality, wildlife resources, and whether the feedstock is a potentially invasive species or can harbour them. These direct effects are generally determined based on direct land use change from annual crops, managed perennial vegetation (e.g., perennial pastures, industrial or non-industrial forest plantations), or other types of perennial vegetation (i.e., natural forest or grassland). Although conversion of natural grasslands or forests to bioenergy crops may occur, both USDA regulations concerning conversion of natural grasslands and stated policies for biomass sources are meant to avoid conversion of native vegetation. Most of the direct environmental effects of cellulosic biomass production will come from existing agricultural land (pasture and row crop), existing forest plantations, or previously harvested forest land. Direct land use effects are based on our understanding of the changes in field, landscape, and watershed attributes when dedicated feedstock crops replace other land uses or covers. Direct effects (all of which can be either positive or negative) include GHGs; soil quality (including but not limited to soil carbon); water quantity and quality; invasive species; and wildlife habitat. Some of these factors can lead to direct effects on adjacent ecosystems and some can lead to larger effects at the watershed or landscape scale. The effects will also be dependent on where bioenergy crops are produced. For instance, there may be net environmental benefits (especially GHG and soil/water benefits) from conversion of cropland to warm season grasses or to short rotation woody crops but for conversion from forest, managed for saw timber production, to biomass there may not be any net benefits. The scale of benefits also depends on the land converted with the general idea being that the less productive and more marginal the land, the greater the benefit from conversion to perennial cellulosic biomass crops.