Progress 09/01/13 to 08/31/16
Outputs
Target Audience:Researchers, policymakers, and landowners interested in the productivity and economics of woody biomass crops. Changes/Problems:As mentioned in the annual report for the first year, the work was slowed for Objectives 1 and 2 by the need to develop a methodology to account for the various management practices (e.g. planting densities, fertilizer rates, weed control, etc.) which greatly influenced the productivity reported in the different yield studies from the literature. In order to complete the remaining work, a request for a one-year no-cost extension was submitted on July 7, 2015. Under the extension, it is anticipated that Objective 3 will be completed by August 31, 2016. Also in July 2015, this grant was relinquished from Iowa State University to the University of Arkansas, and we are in the process of converting this fellowship award into a standard grant. Thus plans for the next/final year, completing the economic analyses and publishing the results of the research in a peer-reviewed journal, will take place under a University of Arkansas project. What opportunities for training and professional development has the project provided?Training in Responsible Conduct of Research (RCR) was completed under the project. Also, I had the opportunity to provide training to an undergraduate honors student on the subject of data management (~8 hours). Finally, the project directors' meeting provided the opportunity to meet and network with NIFA personnel and other fellowship researchers from around the country. How have the results been disseminated to communities of interest?A poster presentation for the project was given in August, 2015 (see publications section). What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
The goal of this project is to better inform woody crop selection and improve economic performance on marginal lands in the southeastern USA. The modeling efforts for this project have resulted in the development of productivity estimates for three major woody biomass crops for the Southeastern region. This information has in turn been used to develop maps showing the estimated productivity of each crop across the gradients of soil and climate conditions in the region. In combination with the ongoing economic evaluations, these results are expected to provide valuable information to policymakers and landowners about the potential yields of these crops, the amount of time for the crops to reach maximum productivity (aka rotation length), and the possible economic returns associated with each crop. Objective 1. Adapt the 3-PG model for poplars, loblolly pine, and eucalypts within the region, using previously-published calibrations for these species as a starting point, and further calibrating and validating the model with existing plantation yield data. Using the yield, soil, and climate data compiled during the first year of the project, the model fitting procedures were completed during the second year of the project. More specifically, regression modeling was used to quantify species responses to various management actions (irrigation, fertilization, weed control, etc.). After accounting for these differences in management practices, the model fitting procedures were completed and the performance of the model was improved in comparison to using only climate and soils data to fit the model. Objective 2. With the validated model from Objective 1 and existing GIS layers for soils and climate, generate productivity estimates for marginal lands within the region by climate zone and soil type. Using the compiled climate and soils data from the first year along with the fitted model from the second year, regional productivity estimates were generated for each species. More specifically, productivity estimates for each species were generated for each soil type (as broadly defined in the 3PG model) within each climate division (multi-county areas with a common climate as defined by NOAA). The resulting estimates were used to develop regional productivity maps for each species, and provide a basis for comparing optimal rotation lengths and economic value of each species for different areas within the region. Objective 3. With the productivity estimates from Objective 2, determine the optimum rotation age and land expectation value (LEV) for each species, as well as the economically optimum species (i.e. highest LEV) by climate zone and soil type. A request for a one-year no-cost extension was submitted on July 7, 2015. Under the extension, the productivity estimates generated from Objectives 1 and 2 will be used to complete this final objective of comparing the optimal rotation ages and economic value of each species. This information is expected to be useful for helping policymakers and landowners make better-informed decisions about which species are most suitable and economically viable under the different combinations of soil and climate conditions within the region.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2015
Citation:
Headlee W, Hall R, Zalesny R, Langholtz M. Optimizing Woody Biomass Management and Economics in the Southeastern USA. Proceedings of USDA NIFA Fellowship Project Directors' Meeting, August 4-5, 2015, Washington, DC. p. 31-32.
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Progress 09/01/13 to 08/31/14
Outputs
Target Audience: Students, researchers, and other professionals from the academic, government, and corporate sectors who are interested in the productivity and economics of short rotation woody crops. More specifically, those who attended the 10th Short Rotation Woody Crop Operations Working Group Conference (list of presenters available at: http://www.woodycrops.org/NR/rdonlyres/FDB6F2EF-F47B-4908-BB82-7CE3D494CD3E/4095/agendaSRWC.pdf)and the 6th International Poplar Symposium (list of attendees available at: http://www.2014ipsvi.com/images/stories/List_of_IPS_VI_Participants_Final.pdf). Changes/Problems: We have not encountered major changes/problems in approach during the first year of the project, but we anticipate that we may encounter such a challenge in the second year, specifically in relation to the budgeting for fringe benefits. We budgeted for a fringe benefit rate of 22%, which was the average provided by our Office of Sponsored Programs Administration (OSPA). While the actual rate during the first year of the project has been closer to 29%, we have been able to compensate for this by assigning the institutional allowance to fringe benefits and reducing my annual pay raise from 3% to 1% (which is the minimum allowedfor an employee with satisfactory performance). However, OSPA has indicated that the average fringe benefit rate is increasing to 33% for the second year of the project, and the actual rate may again be higher than their average. In order to compensate for this unanticipated increase in the fringe benefit rate, we expect that we may need to make significant changes during the second year in terms of re-budgeting, seeking additional funding, and/or ending the project 1 to 2 months earlier than originally planned. What opportunities for training and professional development has the project provided? I traveled to the USFS Northern Research Station Institute for Applied Ecosystem Studies in April 2014 to receive training from my collaborators on how to obtain and process large spatial datasets. This training has allowed me to gather and compile all of the spatial climate and soils data needed for the project. Also, I attended two professional meetings in July of 2014. The first was the 10th Short Rotation Woody Crop Operations Working Group (SRWCOWG) Conference, which is held once every two years. The second was the 6th International Poplar Symposium (IPS) Conference, which is held once every four years. In addition to presenting my research, these conferences allowed me to network with professionals from the academic, government, and corporate sectors, which contributed to my being selected as chair of the technical program for the next SRWCOWG conference in 2016. How have the results been disseminated to communities of interest? As alluded to above, I shared the preliminary results of the project (including the development and testing of crop-specific equations for growth responses to management) at two conferences in July 2014. More specifically, I gave an oral presentation titled “Using Process-Based Modeling to Inform SRWC Species Selection and Management in the Southeastern USA” at the 10th SRWCOWG Conference in Seattle, WA (July 17-19), and a poster presentation titled “Comparing Poplars to Eucalypts and Loblolly Pine on Marginal Lands in the Southeastern USA – Preliminary Results” at the 6th IPS Conference in Vancouver, BC (July 20-23). Per the terms of the grant, I also established a LinkedIn profile that includes a description of the project and can be viewed by my Connections (of which I currently have 53) as well as other LinkedIn users. What do you plan to do during the next reporting period to accomplish the goals? Objective 1: We will use the detailed climate and soils data that we have gathered, along with the crop-specific equations we developed for quantifying responses to management practices, to test the previously-published model calibrations against the calibration data that we have compiled for each woody crop. If needed, we will adjust the model settings to improve the fit of the model to the calibration dataset, and then will test the calibrated model against the validation data that we have compiled for each crop. We expect to complete these final tasks for Objective 1 by the end of October 2014. Objective 2: We will use the validated model, along with the spatial data that we have compiled for climate and soils, to generate productivity estimates for each crop on marginal lands across the study region. We will then add these productivity estimates back into the GIS layers for climate and soils, which will allow us to compare and map productivity for each crop by climate zone and soil type. We anticipate completing these final tasks for Objective 2 by the end of December 2014. Objective 3: We will use the productivity estimates from Objective 2 to determine the most economically feasible crop(s) by climate zone and soil type. Specifically, we will evaluate the productivity estimates to determine the economically optimal rotation age for each crop by climate zone and soil type, determine the land expectation values (LEVs) at these optimal rotation ages, and compare the LEVs for each crop to determine which is economically optimal (highest LEV) for each climate zone and soil type. To support these efforts, I will travel to Oak Ridge National Laboratory and receive training from my collaborators on how to conduct the economic analyses. We anticipate completion of these tasks by the end of the grant period on August 31, 2015.
Impacts
What was accomplished under these goals?
Impact Statement Short rotation woody crops (SRWC) can provide biomass for sustainable bioenergy and stimulate rural economies, while minimizing impacts on the food supply and preserving environmental quality when placed on marginal lands. Although past SRWC research provides valuable insights into the performance of certain species in selected environments, studies comparing an array of species side-by-side across a wide range of conditions are lacking. Computer models that account for environmental influences on tree growth (i.e. process-based models) can be used to directly compare species performance across a range of climate and soil conditions. In this project, the Physiological Principles Predicting Growth (3-PG) model is being adapted to predict the growth and yield of poplars, eucalypts, and loblolly pine on marginal lands in the southeastern USA, in order to better inform woody crop selection and optimize economic performance. With guidance from his collaborating mentors, the project director (Dr. William Headlee) has completed an extensive literature review to identify 45 previously-published studies from the region that contain the necessary site information and growth data to fit (calibrate) and verify (validate) the 3-PG model for these woody crops. From these 45 studies, a total of 1,309 datapoints were extracted, of which approximately half were assigned to the calibration dataset and half to the validation dataset. Detailed climate and soils data needed for model calibration and validation were also compiled for the 28 counties in which the previously-published studies were conducted. Similarly, broad-scale climate and soils data were compiled for the entire five-state area (South Carolina, Georgia, Florida, Alabama, and Mississippi), which along with the validated model will be used to estimate the productivity and economic feasibility of each crop by climate zone and soil type. To account for the effects of management practices on productivity, mathematical equations were developed to predict the growth responses of these woody crops to fertilization, site preparation, and weed control. The resulting equations demonstrated moderately strong to very strong fit statistics; specifically, r2 values of 0.57 to 0.88 (on a scale of 0 to 1, where 1 is the best possible fit) were observed. The equations advance current knowledge in the field of study by providing a method for land managers to estimate the yield gains associated with these management practices and weigh them against the economic costs, in addition to providing researchers with a method to account for the effects of management practices on productivity in modeling projects such as this one. The results of the ongoing modeling work and economic evaluations are also expected to advance current knowledge in the field by providing direct comparisons of the productivity and profitability of these woody crops under a wide range of growing conditions, thereby allowing for more rapid and efficient deployment of SRWC onto marginal lands in the region. Accomplishments Objective 1: Adapt the 3-PG model for poplars, loblolly pine, and eucalypts within the region, using previously-published calibrations for these species as a starting point, and further calibrating and validating the model with existing plantation yield data. An extensive literature review was completed in which 72 studies were identified as being potentially useful for calibrating and validating the 3-PG model for eucalypts, poplars, and loblolly pine. Of these, 57 studies were found to contain site-specific data for our variables of interest (tree height, diameter, biomass, and/or survival). Of these, 45 studies were found to contain sufficiently detailed descriptions of the study sites to allow us to obtain the climate and soils data needed for modeling. From these 45 studies, we identified 180 stands (unique combinations of site, planting year, planting density, and management), for which we were able to extract 1,309 data points (unique combinations of stand, growth variable, and measurement age) to be used in model calibration and validation. Approximately half of these data (88 stands with 685 data points) were assigned to the calibration dataset, and the rest (92 stands with 624 data points) were assigned to the validation dataset. In compiling these data, we recognized that differences in management practices resulted in significant differences in productivity within and among sites. In order to better account for this in our modeling efforts, we used the calibration dataset to statistically analyze the growth responses of these woody crops to various management practices. More specifically, we designed and tested equations that quantify the relative shifts in the slopes and intercepts of the crops’ cumulative growth curves associated with fertilization, site preparation, and weed control, under the assumption that the growth response per unit of application would diminish with increasing application rates. The resulting equations showed moderately to verystrong fits (r2 of 0.57 to 0.88) for the various woody crops and growth variables, and will be incorporated into the subsequent calibration, validation, and productivity estimation phases of the project. As their usefulness may extend beyond the current modeling applications, we believe these equations represent an important change in knowledgeworthy of a standalone publication, in addition to those that will be produced from the modeling efforts. The locations of the 45 previously-published studies were used to determine the final study area for the project (i.e., South Carolina, Georgia, Florida, Alabama, and Mississippi). This information was also used to produce a map of the study area, which specifically highlights the 28 counties in which the previously-published studies were conducted. In addition, we have finished compiling detailed soils data (SSURGO) and climate station data (monthly temperature, precipitation, and solar radiation from 1961 to 2010) for these 28 counties, which will be used to complete the model calibration and validation phase of the project. Objective 2: With the validated model from Objective 1 and existing GIS layers for soils and climate, generate productivity estimates for marginal lands within the region by climate zone and soil type. We have obtained the broad-scale spatial soils (STATSGO) and climate (NARR) data needed for the productivity modeling phase of the project, with 100% spatial coverage. Using the soils data, we have also identified and mapped the land base thatmeets our definition of marginal lands (i.e., NRCS Land Capability Classes II through IV), which consists of about 40 million hectares or approximately 60% of the total land area in the region. We will use this land base whichwe have identified asmarginal landsto generate productivity estimates with the validated model upon completion of Objective 1 (above). Objective 3: With the productivity estimates from Objective 2, determine the optimum rotation age and land expectation value (LEV) for each species, as well as the economically optimum species (i.e. highest LEV) by climate zone and soil type. Awaiting completion of Objective 2 (above).
Publications
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2014
Citation:
Headlee W, Hall R, Zalesny R, Langholtz M. Using Process-Based Modeling to Inform SRWC Species Selection and Management in the Southeastern USA. 10th Short Rotation Woody Crop Operations Working Group Conference in Seattle, WA, July 17-19 2014. (oral presentation)
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2014
Citation:
Headlee W, Hall R, Zalesny R, Langholtz M. Comparing Poplars to Eucalypts and Loblolly Pine on Marginal Lands in the Southeastern USA Preliminary Results. 6th International Poplar Symposium Conference in Vancouver, BC, July 20-23 2014. (poster presentation)
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