When oil prices peaked at over $140 per barrel, alternative energy gained a new urgency. One alternative particularly relevant to the Rockies is woody biomass from forests. Burning wood for energy is hardly a new idea—wood has warmed humans since we learned to use fire—but now it is heralded a safe, renewable way to generate electricity or even liquid fuel.
In 2008 alone there more than 65 major new wood energy projects in North America and as many as 50 more in the planning stages.
Many of these plants have been sited in the Rockies, including an $88-million dollar plant in Grand Junction, Colo., to convert trees to liquid fuel. However, not all projects are large.
The Fuels for Schools program has converted nine schools in Montana to heat with wood, and two more are in progress.
The U.S. Department of Energy has set a goal to increase domestic biofuels use from about 2.1 billion gallons to 51 billion gallons by 2030 and to more than double bioenergy use. A substantial portion of the biomass needed to fuel this renewable energy growth may come from forests. In fact, one report estimates U.S. forests could yield 368 million dry tons of useable biomass per year, which is two and half times estimates of current woody biomass use.
Part of the attraction of using woody biomass for energy is that it can provide additional benefits. Use of wood as a replacement for fossil fuels has the potential to reduce greenhouse gas emissions and contribute to climate change mitigation. Colorado Gov. Bill Ritter, Jr. sees bioenergy from woody biomass as "a clean way to produce heat while addressing problems associated with beetle kill and using waste products from fire mitigation efforts."
Rising energy costs, concerns about carbon emissions from fossil fuels, and risks associated with catastrophic wildfires all contribute to a bright future for bioenergy from woody biomass. The catch is how to move it from the woods to the consumer. To understand how foresters and other natural resource managers are dealing with woody biomass removal, the Forest Guild collected 45 case studies from parks, conservation lands, private forests, tribal lands, state holdings and federal ownerships across the United States. Through support from the Joint Fire Sciences Program and the U.S. Forest Service Region 3, the Guild built a web site that presents each case study in detail. The web site allows users to search by project location, forest type, products generated, type of contract, primary treatment objectives, and land tenure.
In addition, our report, Synthesis of Knowledge from Woody Biomass Removal Case Studies provides an in-depth analysis of the case studies. We have identified themes, strategies, and lessons learned from these case studies by working with an advisory council of land managers, academics, line officers, representatives from nonprofit organizations, and administrators.
Our report and case studies focuses on the forest side—the planning, harvesting, gathering, and transporting—of biomass removal. There are a number of other resources that provide insight into different aspects of woody biomass removal, including:
What is woody biomass?
One of the first issues is to be clear about is the term “woody biomass.” Technically, it includes all the trees and woody plants in forests, woodlands or rangelands. This biomass includes limbs, tops, needles, leaves and other woody parts.
In practice, woody biomass usually refers to material that has historically had a low value and cannot be sold as timber or pulp. Biomass harvesting might even remove dead trees, downed logs, brush and stumps, although most guidelines recommend against this practice.
Markets determine which trees are considered sawtimber material and which are relegated to the low-value biomass category. Different kinds of material are labeled biomass as markets change over time and from region to region, but in general it is a very low-value product.
In our report, the term woody biomass refers to vegetation removed from the forest, usually logging slash, small-diameter trees, tops, limbs, or trees that cannot be sold as higher-value products such as sawtimber.
Because woody biomass is a low-value and high-volume product, transporting it from the forest to the consumer presents economic challenges. Even with increasing interest in the utilization of woody biomass, harvesting and transporting it is relatively costly because smaller stems have high handling costs and most forest harvesting systems were originally designed for larger-diameter timber. The 45 case studies demonstrate how forest managers across the country have risen to the challenge and developed a wide variety of strategies, funding sources, and prescriptions for removing biomass.
Seven main themes emerged from comparing the biomass removal case studies: objectives, collaboration, ecology, fire, economics, implementation, and regional differences.
Objectives
Biomass removal projects tend to combine multiple objectives such as ecological restoration, wildfire hazard reduction, forest-stand improvement, rural community stability, employment and habitat improvement. Although much attention has been focused on biomass removals where the main purpose is fuel reduction, it is important to recognize that many projects are driven by silvicultural or restoration aims.
Forest managers often want to remove small-diameter or otherwise low-value trees to increase the growth of the remaining trees or to permit new seedlings to grow. These silvicultural objectives are easier to achieve when markets and infrastructure reduce the cost of biomass removals. Restoration objectives are often required with biomass removal where fire is the dominant disturbance regime, but in some cases the objective may be to grow bigger trees faster to replicate late successional (i.e., old growth) forest conditions as soon as possible.
Collaboration
Due to their complexity, novelty and potential for conflict, biomass removal projects benefit significantly from collaboration. Biomass removal projects may face more workforce problems than standard timber harvests because fewer contractors are willing to tackle the difficulties of moving high-volume, low-value material. In areas with well-trained and efficient workers, successful projects result from partnerships between land managers and contractors. Public participation in projects can make the public feel more comfortable with forest management decisions. Stewardship contracting, a federal contracting authority focused on meeting both land management objectives and community needs, presents a flexible way to develop partnerships and invite constructive public involvement.
Ecology
Almost every case study in our analysis contained some element of ecological restoration, watershed management or habitat improvement. In some cases, the restoration element was limited to reducing the potential for uncharacteristic wildfires and the resulting negative ecological impacts. Biomass removal projects continue to raise concerns about ecological impacts partly because of increased demand for biomass utilization. Forest managers and the public have expressed concern that removal of more biomass from forests could impact site quality or nutrient status. However, few projects reported rigorous ecological monitoring. The ecological impacts of biomass removals, both positive and negative, need more research. States and non-governmental organizations are creating guidelines for biomass harvesting that may help to protect forests and alleviate concerns about the impact of removals.
Fire
Fire hazard reduction drives biomass removal projects in most fire-adapted forests. The unprecedented scale and cost of recent wildfires across the Western U.S. have drawn public attention to the problem of unnaturally dense, at-risk forests. There is a widespread push to reduce fuels—live and dead biomass—that have accumulated during many years of fire suppression policies. In addition to the basic desire to reduce fire hazard, the case studies demonstrate the effectiveness of fuels treatments on controlling fire behavior and the importance of prescribed fire in maintaining fuel-reduction benefits.
Economics
Although some biomass removal projects have been able to generate a profit or at least break even, most projects included in this report were subsidized. Some managers generated a profit by combining multiple forest products in the removal, taking advantage of fluctuations in the biomass market, and selling to established outlets. Contractors, utilization markets, haul distances and the mix of removed products all affected profitability. While a short-haul distance from forest to utilization would lower project costs, our case studies indicated that long-haul distances would not necessarily doom a project to failure.
Implementation
Many biomass removals rely on hand felling and traditional skidding operations. However, in our case studies some of the more profitable operations were also more mechanized. Machines designed for biomass removal are beginning to move from the experimental phase to everyday operations and may make future projects more efficient . Some projects require multiple contractors, each focusing on a different portion of the project. For example, one contractor cuts sawlogs while another cuts biomass.
Regional Differences
In some Eastern hardwoods forests, biomass harvests focus on removing poorly formed, diseased, or stressed trees to improve remaining crop trees. The overriding driver for biomass removal in Western coniferous forests is a reduction of fuels, although forest-stand improvement does occur. Perhaps the most important lesson to draw from regional differences in biomass removal is that project specifics should be driven by the biophysical conditions and social context of each site.
Taken together, these case studies illustrate that all aspects of woody biomass removals, from markets to mechanization, are evolving. Synthesis of Knowledge from Woody Biomass Removal Case Studiesidentifies the building blocks for successful biomass projects—particularly public involvement, partnerships with contractors, and judicious mechanization of harvest operations—that are present in the management of many forests across the country.
As Research Director at the Forest Guild, Dr. Alexander Evans studies ecological forestry, sustainable biomass removal and the carbon impacts of forest management. Dr Evans’ past research includes the impact of hemlock woolly adelgid on eastern forests and an investigation of factors that influence wind storm impacts on forests. He received his PhD for the Yale School of Forestry and Environmental Studies after working as a cartographer and spatial analyst with the US Geological Survey. |
