The Department of Energy has been involved in the development of suitable plant materials and techniques for short-rotation woody crops since 1979 for energy and wood products. As program managers for the energy program, Oak Ridge National Laboratory scientists developed a regionally and nationally integrated approach to improving, testing and deploying woody crop plant materials. This has involved integration among universities, the USDA Forest Service, private and state nurseries and many pulp and paper companies. The most integrated regional program and the best progress has occurred in the Pacific Northwest where over 20 new hybrid poplar clones are in commercial use for fiber production, over 65,000 acres are in commercial production, and two industry research cooperatives have formed. In the North-central region, only 6-8 clones are currently suitable for commercial use but over 60 new hybrid poplar clones are in their 3(rd) year of clone/site testing and over 200 are in early selection phases. Disease and pest resistance is a major selection criteria. In the South, a new breeding effort for poplars is building on a few selections released by the USDA Forest Service in the 70's plus new germplasm being collected several major river drainages. Other species recently or currently under investigation in the south include sweetgum, sycamore and black locust. The Northeast has the newest crop development program focusing on hybrid willows. All crops are being developed for multiple product use.

We update the technical status of wood feedstock production and highlight areas where the technology used to produce energy crops has changed since publication of an earlier paper. Most of the research findings presented earlier still hold, but the target dates for achieving them are in the distant future. We estimate current delivered costs in the range of about $2.30/GJ in the Pacific Northwest to a high of about $3.30/GJ in the Midwest cornbelt. Elsewhere costs are about $2.60 to $2.90/GJ. Increasing productivity and lowering harvesting costs can reduce delivered costs by about $0.50/GJ in the Northeast, Southeast, and Lake States, $0.70/GJ in the Midwest cornbelt, and $0.40/GJ in the Pacific Northwest. Whether woody crops become viable commercial commodities in the $2.00 to $2.40/GJ price range depends on a number of circumstances related to price and performance comparisons with conventional fuels.

If, as many climate change analysts speculate, industrial and other emissions of CO2 can be offset by substitution of biofuels, large areas of land, including agricultural land, may be converted to the production of biomass feedstocks. This paper explores the feasibility for the Missouri–Iowa–Nebraska–Kansas (MINK) region of the US of converting some agricultural land to the production of switchgrass (Panicum virgatum L.), a perennial warm season grass, as a biomass energy crop. The erosion productivity impact calculator (EPIC) crop growth model simulated production of corn (Zea mays L.), sorghum (Sorghum bicolor (L.) Moench), soybean (Glycine max L.), winter wheat (Triticum aestivum L.) and switchgrass at 302 sites within the MINK region. The analysis is done for both current climatic conditions and a regional climate model-based scenario of possible climate change. Daily climate records from 1983 to 1993 served as baseline and the NCAR-RegCM2 model (RegCM hereafter) nested within the CSIRO general circulation model (GCM) provided the climate change scenario. Crop production was simulated at two atmospheric CO2 concentrations ([CO2]) at 365 and 560 ppm to consider the CO2-fertilization effect. Simulated yields of the perennial switchgrass increased at all sites with a mean yield increase of 5.0 Mg ha−1 under the RegCM climate change scenario. Switchgrass yields benefited from temperature increases of 3.0–8.0°C, which extended the growing season and reduced the incidence of cold stress. Conversely, the higher temperatures under the RegCM scenario decreased yields of corn, soybean, sorghum and winter wheat due to increased heat stress and a speeding of crop maturity. With no CO2-fertilization effect, EPIC simulated maximum decreases from baseline of 1.5 Mg ha−1 for corn, 1.0 Mg ha−1 for sorghum, 0.8 Mg ha−1 for soybean and 0.5 Mg ha−1 for winter wheat. Simulated yields increased for all crops under the RegCM scenario with CO2 set to 560 ppm. Yields increased above baseline for 34% of the soybean and 37% of the winter wheat farms under RegCM/[CO2] = 560 ppm scenario. Water use increased for all crops under the higher temperatures of the CSIRO scenario. Precipitation increases resulted in greater runoff from the traditional crops but not from switchgrass due to the crop’s increased growth and longer growing season. Simulated soil erosion rates under switchgrass and wheat cultivation were less severe than under corn management. However, simulated erosion under switchgrass was considerable in eastern Iowa during the period of crop establishment because of strong winds at that time.

Several woody and herbaceous energy crop species have been selected as high-potential candidates for supplying biomass feedstocks. Successful methods for their establishment and maintenance have been developed. Recommended species vary as a function of region of the country and soil type. Yields are equally variable. The crops that have received the most research and development include hybrid poplars (fast-growing trees) and switchgrass (a perennial grass). Some information is also available on other tree crops, thick-stemmed perennials and annuals. Supplying large volumes of biomass to energy facilities on a daily basis requires that consideration be taken of the harvest timing, storage and delivery characteristics of different feedstocks as well as their yield, cost and energy properties. Our summary suggests that a combination of crops will be needed to provide large amounts of low-cost and environmentally sustainable year-round supplies of biomass feedstocks.

This paper summarizes reports prepared for the U.S. Environmental Protection Agency (EPA) by researchers at the U.S. Department of Energy's (DOE) Oak Ridge National Laboratory (ORNL). It also presents conclusions from a Biomass Energy Strategies Workshop conducted at ORNL. The Biofuels Feedstock Development Program (BFDP) has largely concentrated on the development of dedicated biomass feedstocks, referred to as energy crops. Two general types of energy crops have received the most attention-short-rotation woody crops (SRWC) and herbaceous energy crops (HEC). These cropping systems use traditional food production technologies as a means of maximizing the production of biomass per unit of land. Research focuses on the development of new crops and cropping technologies. The reports prepared for EPA and summarized by this article include discussions of crop production technologies, available land, economic considerations and environmental trade-offs. The discussion of other sources of biomass occurs only in the context of the workshop on biomass energy strategies.

The Department of Energy`s (DOE`s) Biofuels Feedstock Development Program (BFDP) leads the nation in the research, development, and demonstration of environmentally acceptable and commercially viable dedicated feedstock supply systems (DFSS). The purpose of this report is to highlight the status and accomplishments of the research that is currently being funded by the BFDP. Highlights summarized here and additional accomplishments are described in more detail in the sections associated with each major program task. A few key accomplishments include (1) development of a methodology for doing a cost-supply analysis for energy crops and the application of that methodology to looking at possible land use changes around a specific energy facility in East Tennessee; (2) preliminary documentation of the relationship between woody crop plantation locations and bird diversity at sites in the Midwest, Canada, and the pacific Northwest supplied indications that woody crop plantations could be beneficial to biodiversity; (3) the initiation of integrated switchgrass variety trials, breeding research, and biotechnology research for the south/southeast region; (4) development of a data base management system for documenting the results of herbaceous energy crop field trials; (5) publication of three issues of Energy Crops Forum and development of a readership of over 2,300 individuals or organizations as determined by positive responses on questionnaires.

The concept of planting trees as part of a strategy to confront the possibility of global climate change is now widely accepted. As trees grow they remove CO[sub 2] from the atmosphere and thus slow the atmospheric build-up of CO[sub 2], an important greenhouse gas. Within the global-climate-change context, there are two fundamental problems with managing trees to store carbon. First, the magnitude of fossil-fuel related emissions of CO[sub 2] is so large, 6 billion metric tons of carbon per year that it takes very large areas of tree planting to make a significant impact. Second, as trees mature their rate of growth, and hence rate of net carbon uptake, declines. lie large demand on land area suggests that there is a limit to the fraction of total CO[sub 2] emissions that we might reasonably expect to offset with growing trees. The ultimate maturation of forests suggests that there is a limit on the length of time over which offsets are feasible and that we need to ask what to do as the rate of C uptake declines. Acknowledging a that the availability of land will constrain the ability of tree planting to offset industrial emissions of CO[sub 2], wemore » consider how the land which is available can be used most effectively. This report speculates on how much land might be available for a forest management strategy motivated (at least partially) by concerns about climate change, but our principal focus is on how a given land area can be best used to minimize net emissions of CO[sub 2] and how much might be achieved on a unit of land. We do not suggest that carbon management should be the principal criteria for land management, but we discuss the implications if it were. Confronting global and local changes in climate will be one of many objectives in land management and we explore for the most effective strategy for pursuing this objective.« less

The Short Rotation Woody Crop (SRWC) concept has been applied in the establishment of experimental and commercial plantations in both the United States and Brazil. The SRWC concept involves the application of agricultural principles to the production of tree crops for fiber or fuel. Although extensive SRWC research has occurred in the United States during the past 10 to 16 years, commercial applications have been rather limited. On the other hand, Brazil has made considerable progress in producing SRWC on a large-scale commercial basis while simultaneously conducting research. It seems clear that both countries can gain from each other's experience in SRWC experimentation and commercialization. This paper discusses and compares SRWC system developments in both countries and suggests means of improving and expanding SRWC systems use.

A large amount of information on short-rotation woody crops (SRWC) has been assembled at Oak Ridge National Laboratory, the technical manager for the US Department of Energy's Short Rotation Woody Crops Program (SRWCP). A data base management system was developed to manage this information; it contains detailed information about test design, yearly climate conditions, site descriptions, planting stock, test maintenance, and biomass yields. The data base can be queried to produce species-specific biomass yields, comparisons of annual growth on the state and regional levels, biomass yields by planting density, and graphic representations of cultural treatment differences over time. The SRWCP data base is unique because it contains growth and yield data from more than 25 different species along with the associated cultural and climatic conditions of more than 100 sites within the United States. It is certainly the most complete dataset available documenting the early growth patterns of many species of trees.

Short-rotation energy crops can play a significant role in storing carbon compared to the agricultural land uses they would displace. However, the benefits from these plantations in avoiding further use of fossil fuel and in taking pressure off of native forests for energy uses provides longer term carbon benetfits than the plantation carbon sequestration itself. The fast growth and harvest frequency of plantations tends to limit the amount of above and below-ground carbon storage in them. The primary components of plantation carbon sequestering compared to sustained agricultural practices involve above-ground wood, possible increased soil carbon, litter layer formation, and increased root biomass. On the average, short-rotation plantations in total may increase carbon inventories by about 30 to 40 tonnes per hectare over about a 20- to 56-year period when displacing cropland. This is about doubling in storage over cropland and about one-half the storage in human-impacted forests. The sequestration benefit of wood energy crops over cropland would be negated in about 75 to 100 years by the use of fossil fuels to tend the plantations and handle biomass. Plantation interactions with other land uses and total landscape carbon inventory is important in assessing the relative role plantations play in terrestrialmore » and atmospheric carbon dynamics. It is speculated that plantations, when viewed in this context. could trencrate a global leveling of net carbon emissions for approximately 10 to 20 years.« less

Reduction of feedstock costs is necessary, and genetic techniques can be used to increase productivity, thereby lowering costs. Current regional average productivities in the SRWCP range from 7 to 17 dry Mg ha/sup /minus/1/ year/sup /minus/1/ and the best average productivity found in the Pacific Northwest is 32.8 dry Mg ha/sup /minus/1/ year/sup /minus/1/ on hybrid poplar. Average regional productivities in screening trials of the HECP for lignocellulosic crops range from 3.6 to 21.4 dry Mg ha/sup /minus/1/ year/sup /minus/1/. Average annual rapeseed seed yields varied from 0.7 to 4.21 Mg/ha depending on the planting site, with a maximum yield of 5.53 Mg/ha. Breeding and biotechnology are or will be used to improve the yields of the energy crops. SRWCP productivity goals have been met and exceeded in small plots when genetically improved clones have been used. The SRWCP is currently performing genetic improvement research on five tree species and has inserted genes for herbicide tolerance into a hybrid poplar clone. The HECP plans to initiate genetic improvement of selected grass species in the near future. 28 refs., 4 figs., 7 tabs.

Short-rotation woody crops (SRWC) have a significant potential for permanently mitigating carbon dioxide buildup in the atmosphere. The greatest benefit can be derived from growing large amounts of woody crops dedicated to substitute for fossil energy resources. Assuming current production and conversion technologies and a conservative estimate of the viable US land base (35 million acres), SRWC energy could displace 34 to 67 million tons of fossil carbon releases, 3 to 5% of current annual US emissions. Assuming predicted technology advancements and a high estimate of the US land base available for SRWC (103 million acres), SRWC energy could displace 272 to 470 million tons of annual fossil fuel carbon releases. The carbon mitigation potential of SRWC-based electricity production would be equivalent to about 7.5% of current global fossil fuel emissions and 35% of current total US fossil fuel emissions. This document discusses the strategies to mitigate carbon dioxide in the atmosphere. Topics include planting new trees, managing forests, improving forest utilization and using wood as a renewable energy source to replace fossil fuels. 16 refs., 2 figs., 4 tabs.

Annual dry matter production of two different clones of intensively cultured hybrid Populus in two locations was successfully simulated using a model which assumes that dry-matter production by plant communities is proportional to the radiant energy absorbed by the canopy. The model requires as inputs solar radiation and the leaf-area index at any time. Information on Populus growth parameters was obtained from experimental data from Pennsylvania State University (PSU) in College Station, Pennsylvania, and the United States Department of Agriculture (USDA) Forest Experimental Station at Rhinelander, Wisconsin. Long-term average daily values of incident solar radiation were used. The energy absorbed each year by each crop was calculated using Beer's law. The required information on time-course of leaf-area index through a season was simulated using an equation constrained by maximum leaf area, the date of leaf emergence, and the end of leaf fall. Analysis of the PSU and USDA data was performed to evaluate how well it conformed to the energy-conversion model's assumptions and to derive parameter values for a computerized simulation model. Total above-ground production plotted against total absorbed energy gave the expected straight-line relationship for the data from both sites. The PSU data included 1-year production figures resulting in a slope (ϵ) of the dry-matter/absorbed-energy line of 0.00016 kg MJ−1. For 2-year-old and older crops, both PSU and USDA data indicated that ϵ = 0.0007 kg MJ−1 was a reasonable estimate for the clones being evaluated.

Journal Article Hardwood Energy Crops: The Technology of Intensive Culture Get access J. Warren Ranney, J. Warren Ranney 1Task Leader of Genetics and Biotechnology, Short Rotation Woody Crops Program, Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN. Search for other works by this author on: Oxford Academic Google Scholar Lynn L. Wright, Lynn L. Wright 2Task Leader of Genetics and Biotechnology, Short Rotation Woody Crops Program, Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN. Search for other works by this author on: Oxford Academic Google Scholar Patricia A. Layton Patricia A. Layton 3Task Leader of Genetics and Biotechnology, Short Rotation Woody Crops Program, Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN. Search for other works by this author on: Oxford Academic Google Scholar Journal of Forestry, Volume 85, Issue 9, September 1987, Pages 17–28, https://doi.org/10.1093/jof/85.9.17 Published: 01 September 1987