Woody bioenergy is not a new idea; people have been using wood as a fuel for ages. However, rising oil prices, new technologies, and increased interest in renewable energy have spurred renewed growth in this sector. Commercial wood furnaces, pellet factories, power plants, and even liquid fuel refineries are all examples of wood energy facilities that are springing up throughout the region. What does this mean for forest landowners? Is this an opportunity or a risk? This fact sheet gives an overview of the scope and issues involved when considering whether managing a forest for energy production is a good option.
Private forest landowners represent the first step in the woody bioenergy supply chain. They control the feedstock that is used in the production of heat, power, or other energy sources. For example, in Pennsylvania private forest landowners own more than 70 percent of the forest resource. There are numerous potential economic and environmental benefits to forest landowners from bioenergy production, including revenues from biomass sales, forest management cost savings, potential carbon credits, and potential forest health improvements. However, there are also potential negative impacts on forest sustainability if bioenergy harvests are not carried out correctly.
What Is Woody Biomass?
Woody biomass is any woody material from trees or shrubs. In a forest, timber (sawtimber and pulpwood) is usually the most valuable product, so forest woody biomass for energy usually comes from the trees and woody debris or residues that cannot be used for timber. This can include:
- Trees cut during a "thinning" operation when the stand is too densely planted
- Trees left after all other economic materials are removed during a timber harvest, such as twisted or diseased trees
- Cut residues left after a timber harvest, which can include small-diameter logs, branches and limbs, bark, needles, and stumps
Typically, logging residues can make up about 25-45 percent of the tree's biomass when trees are harvested for sawtimber or pulpwood.
Much of the harvesting that occurs in the Northeast, especially unsustainable "high-grade" cutting, leaves large amounts of residues, especially the small-diameter or low-value trees. This results in a forest that becomes less valuable in terms of future timber growth and ecological quality because most of the preferred trees are removed, leaving less desirable species to regenerate. Some logging residues are used in pulp markets, but in areas where the demand for pulpwood has decreased, bioenergy can provide a valuable market for this material.
Other woody biomass sources include mill residues dedicated to short-rotation woody crops (e.g., hybrid poplars and willows) and urban wood waste. In some cases woody biomass is combined with other biomass sources such as agricultural residues, perennial grasses (e.g., switchgrass), or municipal solid waste.
What Are the Products and Markets for Woody Biomass?
Woody biomass can be converted into useful forms of energy (heat or electricity), valuable bio-based fuels (i.e., solid, liquid, or gaseous fuels), or other products (e.g., polymers, bio-plastics, biochar, sorbents, and acids) using a number of different processes. Thermochemical processing, one of the most common processing methods, uses heat and chemical action as a means of extracting and creating products and energy. Biochemical processing, another common approach, depends on microbes, enzymes, and other biological processes to transform the biomass.
Most landowners are familiar with products that go directly into heat, such as cordwood (for residential use) and chipped wood (for commercial and industrial use). The most important characteristics that define these products are size, moisture content, and "cleanness" (presence of soil, sand, or bark) of chips.
Wood bioenergy markets are complex. Woody biomass is used across a range from small to large scale and from low to high value. At the low value and small scale, residential heat represents the largest share of wood used as a fuel in the United States. Many houses have wood heating and wood pellet furnaces. Commercially, heat, perhaps using gasification technologies, is used in public institutions, including schools, hospitals, prisons, and municipality-owned district heating projects. Heat is also used for industrial processes such as sawmills, which may also produce electricity. One of the most common bioenergy markets includes bioenergy facilities within the forest industry that produce most residues internally.
Woody biomass becomes more valuable when used for co-firing in coal plants or co-generation such as for combined heat and power (CHP) generating facilities. Alternately, the woody biomass can be processed into a higher value fuel such as wood pellets or briquettes. These facilities often prefer mill residues rather than biomass direct from the woods because of the clean, dry nature of mill chips. Newer technologies just emerging on the market include manufacture of liquid fuels for transportation such as cellulosic ethanol (either through thermochemical or biochemical conversion processes) as well as a range of biochemicals. While the majority of fuel ethanol continues to be produced from food-based feedstocks such as corn and sugarcane, there is a large opportunity to use woody biomass feedstocks for ethanol. Technological advances and research into how to make this process affordable are promising.
In most of the northeastern United States there is quite a lot of low-use wood not utilized in any markets. In Pennsylvania, some studies estimate that six to eight million dry tons per year of sustainably harvestable low-use wood is not being used. However, there is currently little demand for either logging residues or small-diameter timber. Most of the current demand for these woody materials comes from pulp mills. However, the pulp and paper industry has declined so much in the region that landowners have relatively few choices of markets for biomass within an economic haul distance from their forestland.
As biomass markets emerge, there will be increased competition between pulp and biomass markets in those few places where pulp markets are still strong. Both markets use wood chips, and depending on distance between facilities and overlap in the areas where they source their wood, wood chip prices may rise due to increasing competition between facilities.
Is Energy from the Forest a Good Idea?
Many in the forestry community are excited about the potential economic and ecological benefits from a growing bioenergy sector. However, some people are concerned that it may be a step in the wrong direction. Here are some of the key arguments on both side of the debate.
Arguments in Favor of Wood Energy
- Biomass harvests will pay for the removal of undesirable species and "weed trees" that landowners couldn't afford to clear out in the past.
- Biomass harvests will supply clean, renewable energy.
- Bioenergy harvests and utilization will generate local jobs.
- Bioenergy is cost effective, especially when compared to fuel oil.
- Forests are like a garden--they need to be tended to and cared for. Bioenergy harvests are a great tool for doing just that.
Arguments Against Wood Energy
- Unscrupulous landowners or loggers will overharvest, destroying or permanently damaging the forest.
- Burning things pollutes the air and contributes to climate change.
- Wood harvesting and use do not provide good jobs.
- We have lots of cheap natural gas and other fossil fuels to use, in addition to solar panels and windmills.
- Forests are a wild preserve that should be left untouched by human hands whenever possible.
The Ecological Side of Things
One of the biggest controversies surrounding woody bioenergy is the question of how it will impact the forest ecosystem. Woody biomass has several advantages compared to fossil fuel in terms of lower carbon emissions, reduced threats of acid rain, and less particulate emissions. In addition, using woody biomass can potentially help regenerate the forest and improve forest health, biodiversity, and wildlife habitat. However, questions exist about sustainability, especially as it pertains to long-term site productivity. A commonly expressed environmental concern about harvesting biomass for energy is that soil nutrients, organic matter, and moisture-holding capacity may be depleted by intensive harvesting methods. Impacts on the inherent fertility of sites depend on harvest intensity and length of the rotation. Generally, shorter rotation and more intensive harvests deplete fertility sooner. Nitrogen and other elements are abundant in twigs and foliage so that harvesting all aboveground biomass could theoretically remove a large proportion of nutrients. However, the vast majority of nutrients are in the leaves and smallest twigs--parts of the tree that are almost never harvested. This matter is far from clear cut, but it appears that most bioenergy harvest practices do not have a big impact on soil fertility.
There are certainly more points to consider than the ones mentioned here, but whether you support or oppose the use of wood for energy probably depends on your philosophy of what a forest should be and whether or not people will properly care for the forest. If wood energy is something that sounds like a good idea, you still need to assess whether or not managing the forest for energy production makes sense economically, politically, and socially in your location.
Politics and Wood Energy
Many states in the Northeast have developed forestry best management practices (BMPs) for water quality, wildlife habitat, and other environmental considerations. In fact there are some specific BMPs and biomass harvesting guidelines. In Pennsylvania, BMP recommendations for woody biomass harvest are available from the Department of Environmental Protection. Private landowners are not required to follow BMP guidelines, but they are a good guide for determining how to sustainably manage your forestland.
Different definitions and resultant guidelines and policies define what actually qualifies as woody biomass. These definitions mainly pertain to public lands. Financial and tax incentives are available for "producers" of woody biomass, mainly through state and federal subsidy payments. At the federal level, several current legislations, such as the Energy Policy Act of 2005, the Healthy Forests Restoration Act of 2003, and the Farm Security and Reinvestment Act of 2002, address the provision of such incentives. While federal programs are the most visible, many states also have incentives for businesses interested in developing renewable energy sources. Many of these incentives are in the form of tax credits. As carbon-offset policies and markets develop, more incentives for forest and bioenergy production will emerge.
Given the largely private and fragmented ownership of forest land in the Northeast, a diverse range of social values will influence bioenergy development through public policy. Development of bioenergy facilities is often touted as benefiting local communities through economic development and job creation.
The Economics of Forest Management for Energy
Wood is generally a low-cost fuel, but the price can be extremely variable. Main factors influencing the price of woody biomass as a fuel include costs of getting the wood from forest to product, regional and international wood trade, and competing products. Costs that go into producing biomass products include collection, processing, and transportation. These production costs vary significantly based on the following:
- Logging system and equipment used
- Volume per acre and total volume per site
- Contractor experience
- Road access and conditions
- Distance to market
It can sometimes cost more to collect, harvest, and transport logging residue or small-diameter wood to a biomass conversion facility than the value of energy that can be made from it. A lot depends on the distance from the woods to a bioenergy facility. On average, transportation costs often account for more than half the delivered cost and can be as high as 70 percent. About 50 miles from a forest site is often recognized as the maximum distance someone would be willing to collect and transport forest biomass. Given the high costs of production and delivery, the amount of money left to compensate the landowner is, at best, a few dollars per ton. As the woody biomass market develops, this amount will likely increase.
In the short term, woody biomass for bioenergy production will primarily come from logging residues and small-diameter timber. Typically, a timber harvest in the Northeast is intended for the higher value sawtimber, and unless there is a pulp market, very little low-use wood is removed. Presumably, as bioenergy production increases, there will be more demand and higher prices paid for these products, making forest management more profitable. Higher prices will be paid for woody biomass, giving larger financial returns than would have been available. In addition, harvesting more of the low-use material may help reduce regeneration costs (if any) and improve wildlife habitat and long-term forest health. Finally, as carbon markets emerge, landowners may be paid for additional wood growth in their forests, much of which can be facilitated by more frequent biomass harvests.
Managing Your Forest for Bioenergy
The Big Picture
Currently, much speculation exists about how new bioenergy markets will affect forest management decisions. Certainly a key question landowners will have is how biomass harvests will affect their land. Related questions are at what "stumpage" price will landowners be willing to allow biomass harvests on their property and how much land should be dedicated to biomass harvests. Landowners differ widely in management objectives, how much timber and/or biomass they want to harvest and sell, and at what price. Many surveys have shown that private landowners are often not focused on timber management as a key objective, but rather on enjoying their land more for personal and recreational uses.
Bioenergy production can increase silvicultural options for forest landowners. Opportunities exist to offset management and silvicultural costs through biomass harvesting, making it affordable to manage the forest better while increasing stand productivity. Bioenergy is a market for wood that is otherwise not saleable, which allows for more flexibility in cutting and management options. For example, without bioenergy markets available, "pre-commercial" thinning may not be carried for lack of revenue to cover harvesting costs. With biomass markets in place, the thinning operation becomes "commercial" and pays for itself plus possibly providing income to the landowner. As more material is removed from the forest, landowners should also be aware of increased "wear and tear" on roads, increased disturbance at landings and chipping sites, and perhaps more administration and monitoring costs.
Depending on your objectives as a landowner, a variety of other benefits can be realized from biomass harvests. Wildlife habitat management practices that require decreased tree density in the forest will be more feasible with potential economic returns. Forest health will be improved by removing insect- and pest-damaged timber, understory hazard fuels, and biomass from invasive plant species.
At one extreme, the landowner may carry out a one-time biomass harvests to help improve natural forests or, at the other extreme, convert some land to intensive short-rotation woody crop plantations (SRWC). Natural forests can be enhanced by tree planting after harvests to increase biomass production. The rationale for shifting toward more biomass production is that the rotation length is a lot shorter than when managing for sawtimber and other higher valued products. With shorter rotations come more regular revenue streams and perhaps quicker return on investments. However, SRWC production requires relatively flat land that "field equipment" can access.
If a biomass market is available, landowners should consider biomass when planning timber sales. If harvesting small-diameter trees, understory, tree tops, and branches is appropriate in accomplishing the objectives of the timber harvest, then biomass should be listed in any timber sale advertisement or prospectus.
Keys to Successful Biomass Harvesting
- In most cases biomass extraction will complement higher value timber harvest. During harvest planning consider biomass possibilities by understanding your local market and their fuel specifications (how much bark, how much dirt, etc.). Find out what are they paying for feedstock and what is driving that.
- Understand the degree to which biomass management is synergistic or creates tradeoffs with other land use goals such as recreational uses, site aesthetics, wildlife habitat diversity, and increased timber values. Also consider such factors such as the personal contribution toward regional "green energy" production.
- Realize the total costs and acceptable profit from not only the biomass harvest itself but from future forest management decisions, including environmental impacts.
- Plan any biomass harvesting with a well-trained forester and/or logger familiar with biomass markets and negotiate price and clarify expectations before starting.
- Plan for biomass recovery during harvest planning and integrate recovery with the logging operation.
Where to Go from Here
Probably the first thing to do is to hire a professional forester to inspect your land. The forester can tell you how much wood you have growing and whether or not a biomass harvest plan would make sense. At this point, you can start to decide exactly what role bioenergy will play in your forest management plan. Professional foresters can probably recommend possible buyers for your forest biomass and give an estimate on prices and costs. Sometimes you can only find a logger to harvest your biomass if they can have it for no cost. For some landowners, this is fine, if the resulting forest is in better condition. However, it doesn't hurt to shop around a bit.
Currently, forest management for biomass energy is not widely practiced, except in a few locations where wood use for heat is common. Woody biomass to energy will likely continue to function mostly as a by-product of value-added wood use. However, as the number of facilities using wood for energy continues to grow, more forest landowners will be able to use wood energy harvests as a tool to improve their forestland and improve their economic bottom line as well. New opportunities for utilization of forest biomass will depend on markets, government policies for renewable energy, and government subsidy programs to encourage the construction of new facilities as well as reduce collection and transportation costs.
Landowners should be thinking about their woody biomass as a product that may have low value now but with the potential that it will increase in value over time. Most forest stands can benefit from the utilization of biomass for bioenergy. If biomass harvesting is not done properly, however, it could lead to degraded forest conditions and openings for unwanted and invasive species. Finally, opportunities exist for intensively managed plantations of short-rotation woody crops on marginal or idle lands.
For More Information
See the following Penn State Extension Renewable and Alternative Energy Fact Sheets for further information:
These and other fact sheets are available on the Penn State Extension website. More information is also available online at the forest bioenergy encyclopedia. Contact your Penn State Extension educator or state forester for more site-specific recommendations.
Prepared by Mike Jacobson, associate professor of forest resources, and Daniel Ciolkosz, extension associate, Department of Agricultural and Biological Engineering