Landscape impacts of potential biofuel production scenarios in North Carolina
Ensuring sustainable pathways for the future depends on meeting society’s need for energy while minimizing the ecological impacts of production. Recently, much of the debate on renewable fuel alternatives has focused on the potential for broad-scale biofuel production from annual and perennial crops, but the landscape impacts of this production have not been fully addressed. In the Southeastern U.S., where both forests and agricultural crops will likely be important sources of biomass for biofuels, addressing these impacts is essential. We expect impacts via four major types of landscape change: conversion of natural forests to intensively managed forests; increased management intensity in already-managed forests; conversion of non-forest land to forest; and conversion of forest to agriculture. We simulated these types of change for potential biofuel production scenarios in North Carolina, where the state’s goal is 10% of liquid fuels produced from locally-grown biofuels. We used forest timber supply and supply chain economics models to determine the likely magnitudes of forest and agricultural biomass harvesting. We linked those models with state-and-transition landscape dynamics models to simulate the locations of land management and conversion under each scenario.
Results indicate that meeting the state’s goal will require large-scale land conversion and intensification of management, leading to major landscape changes, and that those changes will vary by region of the state. In the Coastal Plain, where pine plantations are currently widespread and 52% of the marginal agricultural lands in the state occur, modeled conversion and management was most widespread. In that region under biomass production scenarios, purpose-grown biofuel crops mainly displaced conventional forestry and agriculture. In the Piedmont, the same types of changes occurred as in the Coastal Plain, but biomass production also caused up to a 20-fold increase in harvest of natural forests. In the Mountains, biomass production affected much less land than in the Coastal Plain, and came primarily from increased management of natural forests. These results suggest that large-scale biofuel production in North Carolina will have major implications for ecosystem services such as water quality and wildlife habitat. Future analysis will relate our spatial results to habitat suitability for bird and amphibian species, and will investigate best land management practices for reducing ecological impacts while acknowledging society’s need for renewable fuels.