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Publications

Abrahamson, L.P., Robison, D.J., Volk, T.A., White, E.H., Neuhauser, E.F., Benjamin, W.H., Peterson, J.M. (1998). Sustainability and environmental issues associated with willow bioenergy development in New York (U.S.A.). Biomass and Bioenergy, 15(1), 17-22.

Abrahamson, L. P., White, E. H., Nowak, C. A., Briggs, R. D., & Robison, D. J. (1990). Evaluating hybrid poplar clonal growth potential in a three-year-old genetic selection field trial. Biomass, 21(2), 101-114.

Abrahamson, L.P., D.J. Robison, and E.H. White.  1988.  Site preparation, weed control and herbicide use in fast- growing hardwood plantations.  In M.C. Vodak (Ed.), Proceedings: Forestry Herbicides in the Northeast 1988 March 15-16, New Brunswick, NJ. Cook College, Rutgers University. (Pp. 73-81).

Abrahamson, L.P.  (1992). Managing insect pests of fast-growing hardwoods. In D.C. Allen & L.P. Abrahamson (Eds.), Proceedings: North American Forest Insect Work Conference, March 25-28, 1991 Denver, CO. General Technical Report PNW-GTR- 294. (Pp. 119ff).

Abrahamson, L.P., R.C. McKittrick, E.H. White, R.F. Kopp, & C.A. Nowak. (1992).  Successful no-till hybrid poplar establishment in New York (Abstract only). Forestry Chronicle, 68(2), 218.

Abrahamson, L.P., T.A. Volk, R.F. Kopp, E.H. White, and J.L. Ballard.  (2002).  Willow Bioenergy Producer’s Handbook (revised).  Syracuse, NY: State University of New York College of Environmental Science and Forestry.  31pp.

Abrahamson, L. P., White, E. H., Nowak, C. A., & Kopp, R. F. (1990). Yield potential of willow in New York State. evidence from two years research in an ultrashort-rotation system. Energy from Biomass and Wastes XIII, New Orleans, LA, USA. 261-174.

Adegbidi, H.G., Briggs, R.D., Volk, T.A., White, E.H., Abrahamson, L.P. (2003). Effect of organic amendments and slow-release nitrogen fertilizer on willow biomass production and soil chemical characteristics. Biomass and Bioenergy, 25(4), 389-398.

Adegbidi, H.G., Volk, T.A., White, E.H., Abrahamson, L.P., Briggs, R.D., Bickelhaupt, D.H. (2001). Biomass and nutrient removal by willow clones in experimental bioenergy plantations in New York State. Biomass and Bioenergy, 20(6), 399-411.

Arevalo, C.B.M., Drew, A.P., Volk, T.A. (2005). The effect of common Dutch white clover (trifolium repens L.), as a green manure, on biomass production, allometric growth and foliar nitrogen of two willow clones. Biomass and Bioenergy, 29(1), 22-31.

Arevalo, C.B.M., Volk, T.A., Bevilacqua, E., Abrahamson, L.P. (2007). Development and validation of aboveground biomass estimations for four Salix clones in central New York. Biomass and Bioenergy, 31(1), 1-12.

Ballard, B.D., S.V. Stehman, R.D. Briggs, T.A. Volk, L.P. Abrahamson & E.H. White. (1999).  Aboveground biomass equation development for five Salix and one Populus clone.  Misc. Report New York Center for Forestry Research and Development (NYCFRD – 99- 01), Syracuse, NY: SUNY-ESF.

Bickelhaupt, D.H., C.A. Nowak, E.H. White, & L.P. Abrahamson. (1988).  Biomass produc­tion and nutrient accumulation of ultrashort-rotation willow and poplar plantations in New York State. Soil Science Society of America Annual Meeting, Nov.27-Dec.2, Anaheim, CA., Agronomy Abstracts, p.290.

Buchholz, T., Luzadis, V.A., Volk, T.A. (2009). Sustainability criteria for bioenergy systems: Results from an expert survey. Journal of Cleaner Production,17(Supplement 1), S86-S98.

Buchholz, T., Rametsteiner, E., Volk, T.A., Luzadis, V.A. (2009). Multi criteria analysis for bioenergy systems assessments. Energy Policy, 37(2), 484-495.

Buchholz, T.S., Volk, T.A., Luzadis, V.A. (2007). A participatory systems approach to modeling social, economic, and ecological components of bioenergy. Energy Policy, 35(12), 6084-6094.

Cameron, K., R.F. Kopp, I. Philips, T.A. Volk, L.P. Abrahamson and L.B. Smart. 2008. Quantitative genetics of traits indicative of biomass production and heterosis in 34 full-sib F1 Salix eriocephala families. BioEnergy Research.1(1), 80-90.

Castellano, P.J., Volk, T.A., Herrington, L.P. (2009). Estimates of technically available woody biomass feedstock from natural forests and willow biomass crops for two locations in New York State. Biomass and Bioenergy, 33(3), 393-406.

Clinch, R.L., Thevathasan, N.V., Gordon, A.M., Volk, T.A., Sidders, D. (2009). Biophysical interactions in a short rotation willow intercropping system in southern Ontario, Canada. Agriculture, Ecosystems and Environment, 131(1-2), 61-69.

Downing, M., Volk, T.A., Schmidt, D.A. (2005). Development of new generation cooperatives in agriculture for renewable energy research, development, and demonstration projects. Biomass and Bioenergy, 28(5), 425-434.

Fain, J.J., Volk, T.A., Fahey, T.J. (1994). Fifty years of change in an upland forest in south-central New York: General patterns. Bulletin of the Torrey Botanical Club, 121(2), 130-139.

Heller, M.C., Keoleian, G.A., Mann, M.K., Volk, T.A. (2004). Life cycle energy and environmental benefits of generating electricity from willow biomass. Renewable Energy, 29(7), 1023-1042.

Heller, M.C., Keoleian, G.A., Volk, T.A. (2003). Life cycle assessment of a willow bioenergy cropping system. Biomass and Bioenergy, 25(2), 147-165.

Keoleian, G.A., Volk, T.A. (2005). Renewable energy from willow biomass crops: Life cycle energy, environmental and economic performance. Critical Reviews in Plant Sciences, 24(5-6), 385-406.

Kopp, R. F., Abrahamson, L. P., White, E. H., Burns, K. F., & Nowak, C. A. (1997). Cutting cycle and spacing effects on biomass production by a willow clone in New York. Biomass and Bioenergy, 12(5), 313-319. doi:10.1016/S0961-9534(96)00077-3

Kopp, R.F., L.P. Abrahamson, C.A. Nowak, & E.H. White. (1991).  Pre-emergent her­bicides for site preparation in ultrashort-rotation willow plantings: Early first-year results. In P. Williams (Ed.), Agroforestry in North America, Proceedings of the First Conference on Agroforestry in North America, August 13-16, 1989. (Pp. 116-121). Guelph, Ontario, Canada:  University of Guelph.

Kopp, R.F., D.H. Bickelhaupt, E.H. White, & L.P. Abrahamson. (1993).  Effect of fertilization on willow biomass production and nutrient removal in a bioenergy system. Soil Science Society of America Annual Meeting, Nov. 7-12, 1993. Cincinnati, OH, Agronomy Abstracts, p. 337.

Kopp, R.F., L.P. Abrahamson, C.A. Nowak, & E.H. White. (1992). Pre-emergent her­bicides for site preparation in Salix plantings. Forestry Chronicle 68(2), 218- 219.

Kopp, R.F., E.H. White, L.P. Abrahamson, C.A. Nowak, & K.F. Burns. (1993). Willow biomass trials in central New York State.  Biomass and Bioenergy 5(2), 179-187.

Kopp, R. F., Abrahamson, L. P., White, E. H., Nowak, C. A., Zsuffa, L., & Burns, K. F. (1996). Woodgrass spacing and fertilization effects on wood biomass production by a willow clone. Biomass and Bioenergy, 11(6), 451-457. doi:10.1016/S0961-9534(96)00055-4

Kopp, R.F., Abrahamson, L.P., White, E.H., Volk, T.A., Nowak, C.A., Fillhart, R.C. (2001). Willow biomass production during ten successive annual harvests. Biomass and Bioenergy, 20(1), 1-7.

Kopp, R. F., Castello, J. D., & Abrahamson, L. P. (1999). Viruses in salix grown for bioenergy. European Journal of Forest Pathology, 29(2), 117-122.

Kopp, R. F., Maynard, C. A., De Niella, P. R., Smart, L. B., & Abrahamson, L. P. (2002). Collection and storage of pollen from Salix (Salicaceae). American Journal of Botany, 89(2), 248-252.

Kopp, R. F., Smart, L. B., Maynard, C. A., Isebrands, J. G., Tuskan, G. A., & Abrahamson, L. P. (2001). The development of improved willow clones for eastern North America. Forestry Chronicle, 77(2), 287-292.

Kopp, R. F., Smart, L. B., Maynard, C. A., Tuskan, G. A., & Abrahamson, L. P. (2002). Predicting within-family variability in juvenile height growth of Salix based upon similarity among parental AFLP fingerprints. Theoretical and Applied Genetics, 105(1), 106-112. doi:10.1007/s00122-001-0855-3

Kuzovkina, Y.A., Volk, T.A. (2009). The characterization of willow (Salix L.) varieties for use in ecological engineering applications: Co-ordination of structure, function and autecology. Ecological Engineering, 35(8), 1178-1189.

Lo, M.H., Abrahamson, L.P., White, E.H., & Manion, P.D. (1995). Early measures of basal area and canker disease predict growth-potential of some hybrid poplar clones. Canadian Journal of Forest Research 25(7), 1113-1118.

Lo, M. H., & Abrahamson, L. P. (1996). Principal component analysis to evaluate the relative performance of nine year old hybrid poplar clones. Biomass and Bioenergy, 10(1), 1-6.

Luzadis, V., Buchholz, T. and Volk, T.A. (2009). A Co-evolutionary Complex Adaptive Systems Approach for Assessing Bioenergy Sustainability. In Renewable Energy from Forest Resources in the United States. (Pp. 196-210). New York, NY: Routledge Press. 

Minor, M.A., Volk, T.A., Norton, R.A. (2004). Effects of site preparation techniques on communities of soil mites (acari: Oribatida, acari: Gamasida) under short-rotation forestry plantings in New York, USA. Applied Soil Ecology, 25(3), 181-192.

Mirck, J., Volk, T.A. (2010). Response of three shrub willow varieties (Salix spp.) to storm water treatments with different concentrations of salts. Bioresource Technology,101(10), 3484-3492.  

Mirck, J. and T.A. Volk, (2010). Seasonal Sap Flow of Four Salix Varieties Growing on the Solvay Wastebeds in Syracuse, NY, USA. International Journal of Phytoremediation.12(1), 1.

Nowak, C.A., E.H. White, L.P. Abrahamson, & B. Barkley. (1988).  Site considerations for the culture of Populus hybrids in New York State. Soil Science Society of America Annual Meet­ing, Nov.27-Dec. Anaheim, CA., Agronomy Abstracts p. 297.

Nowak, C.A., R.F. Kopp, L.P. Abrahamson, E.H. White, & J.G. Sah. (1989).  Biomass production and nutrient accumulation among 1-year-old willow clones grown in a "wood grass" system. SUNY College of Environmental Science and Forestry Faculty of Forestry Technological Publication No. 3 (ESF 89-003), 18p.

Nowak, C.A., E.H. White, L.P. Abrahamson, & R.F. Kopp. (1989).  Physiological basis for increased willow wood biomass with fertilization. Agronomy Abstracts, Madison, WI. p.241.

Nowak, C.A., T.A. Volk, B.D. Ballard, L.P. Abrahamson, R.C. Fillhart, R.F. Kopp, D. Bickelhaupt & E.H. White. (1999).  The role and process of monitoring willow biomass plantations In O.P. Overend & E. Chornet (Eds.), Proceedings of the 4th Biomass Conference of the Americas -   Biomass: A Growth Opportunity in Green Energy and Value-added Products August 29-September 2, 1999, Oakland, CA.  V. 1. (Pp. 25-29). Oxford: Pergamon.

Nordman, E.E., Robison, D.J., Abrahamson, L.P., Volk, T.A. (2005). Relative resistance of willow and poplar biomass production clones across a continuum of herbivorous insect specialization: Univariate and multivariate approaches. Forest Ecology and Management, 217(2-3), 307-318.

Park, B.B., Yanai, R.D., Sahm, J.M., Lee, D.K., & Abrahamson, L.P. (2005). Wood ash effects on plant and soil in a willow bioenergy plantation. Biomass & Bioenergy, 28(4), 355-365.

Park, B. B., Yanai, R. D., Sahm, J. M., Ballard, B. D., & Abrahamson, L. P. (2004). Wood ash effects on soil solution and nutrient budgets in a willow bioenergy plantation. Water, Air, and Soil Pollution, 159(1), 209-224. doi:10.1023/B:WATE.0000049177.60761.37

Pian, C.C.P., Volk, T.A., Abrahamson, L.P., White, E.H., Jarnefeld, J. (2006). Biomass gasification for farm-based power generation applications. Waste Management and the Environment 3(1), 267-276.

Pian, C.C.P and T.A. Volk. 2009. Willow biomass gasification feasibility study. In: Badeau, J-P. and A. Levi. (eds). Biomass Gasification: Chemistry, Process and Applications. (pp. 71-86). Hauppage, NY: Nova Science Publishers.

Robison, D.J., L.P. Abrahamson, & E.H. White. (1994).  Silviculture of wood biomass crops as an energy feedstock. The New York Forest Owner, Sept./Oct., 4-5.

Robison, D.J., T. Rooney, L.P. Abrahamson, & E.H. White. (1994). Wood energy issues in New York. The New York Forest Owner, July/Aug., 5.

Sahm, J.M., E.H. White, & L.P. Abrahamson. (1993). Wood ash applications in willow bioenergy plantations. Soil Science Society of America Annual Meeting, Nov. 7-12, 1993, Cincinnati, OH, Agronomy Abstracts, 338-339

Sahm, J.M., T. Koch, C.A. Nowak, L.P. Abrahamson, & E.H. White. (1994). Utilization of wood boiler ash: An annotated bibliography. SUNY College of Environmental Science & Forestry, Faculty of Forestry Technological Publication Series. No. 5., 44pp.

Sahm, J.M., E.H. White, L.P. Abrahamson, & C.A. Nowak.  (1994). Wood ash applications in willow bioenergy plantations. 85th Annual Meeting of the American Society of Agonomy, 1993 November 7-12, Cincinnati, OH. Madison, WI: Agronomy Abstracts, 339

Smart, L.B., Volk, T.A., Lin, J., Kopp, R.F., Phillips, I.S., Cameron, K.D., White, E.H., Abrahamson, L.P. (2005). Genetic improvement of shrub willow (Salix spp.) crops for bioenergy and environmental applications in the United States. Unasylva, 56(221), 51-55.

Teece, M.A., Zengeya, T., Volk, T.A., Smart, L.B. (2008). Cuticular wax composition of Salix varieties in relation to biomass productivity. Phytochemistry, 69(2), 396-402.

Tharakan, P. J., Robison, D. J., Abrahamson, L. P., & Nowak, C. A. (2001). Multivariate approach for integrated evaluation of clonal biomass production potential. Biomass and Bioenergy, 21(4), 237-247. doi:10.1016/S0961-9534(01)00038-1

Tharakan, P.J., Volk, T.A., Abrahamson, L.P., White, E.H. (2003). Energy feedstock characteristics of willow and hybrid poplar clones at harvest age. Biomass and Bioenergy, 25(6), 571-580.

Tharakan, P.J., Volk, T.A., Lindsey, C.A., Abrahamson, L.P., White, E.H. (2005). Evaluating the impact of three incentive programs on the economics of co-firing willow biomass with coal in New York State. Energy Policy, 33(3), 337-347.

Tharakan, P.J., Volk, T.A., Nowak, C.A., Abrahamson, L.P. (2005). Morphological traits of 30 willow clones and their relationship to biomass production. Canadian Journal of Forest Research, 35(2), 421-431.

Tharakan, P.J., Volk, T.A., Nowak, C.A. and G. Ofezu. (2008). Canopy Structure, Light Interception, and Light-Use Efficiency in Willow. BioEnergy Research. 1(3-4), 229 – 238.

Tharakan, P.J., C.A. Nowak, L.P. Abrahamson, D.J. Robison & T.A. Volk. (1999). Characterization of willow bioenergy clones: A step towards improving yield. Abstract In Proceedings of the 4th Biomass Conference of the Americas - A Growth Opportunity in Green Energy and Value-added Products August 29-September 2, 1999, Oakland, CA.  Addendum to the Proceedings, 26.

Tharakan, P.J., L.P. Abrahamson, D. J. Robison, J.G. Isebrands, C.A. Nowak, T.A. Volk & E.H. White. (2000). Coppice effects on willow and hybrid poplar stem attributes and biomass production. In J.G. Isebrands & J. Richardson (Compilers). 21st Session of the International Poplar Commission (IPC 2000). Poplar and Willow Culture: Meeting the Needs of Society and the Environment. USDA Forest Service General Technical Report NC-215, 175.

Tharakan, P.J., T.A. Volk, C.L. Lindsey, S. Edick, J. Dickerson, P. Ray & L. P. Abrahamson. (2001). A technical and economic analysis of willow biomass crops grown on conservation reserve program land in New York State. Fifth Biomass Conference of the Americas. Sept. 17-21, 2001, Orlando, FL. 2pp.

Tharakan, P.J., C.A. Nowak, L.P. Abrahamson, T.A. Volk, E.H. White, D.J. Robison, & J.G. Isebrands. (2001). Coppice effects on willow and hybrid poplar stem attributes and biomass production. In T.A. Volk, J. Ballard & L.P. Abrahamson (Compilers). Proceedings of the Third Biennial Short-Rotation Woody Crops Operations Working Group Conference, Syracuse, NY October 10-13. Syracuse, NY: SUNY-ESF, 193.

Ulzen-Appiah, F., R.D. Biggs, L.P. Abrahamson & D.H. Bickelhaupt. (2001). Soil carbon pool in a short-rotation willow (Salix dasyclados) plantation four years after establishment. In T.A. Volk, J. Ballard & L.P. Abrahamson (Compilers). Proceedings of the Third Biennial Short-Rotation Woody Crops Operations Working Group Conference, Syracuse, NY October 10-13. Syracuse, NY: SUNY-ESF, 153.

Volk, T.A., Abrahamson, L.P., Nowak, C.A., Smart, L.B., Tharakan, P.J., White, E.H. (2006). The development of short-rotation willow in the northeastern United States for bioenergy and bioproducts, agroforestry and phytoremediation. Biomass and Bioenergy, 30(8-9), 715-727.

Volk, T.A., Ballard, B., Robison, D.J., Abrahamson, L.P. (2004). Effect of cutting storage conditions during planting operations on the survival and biomass production of four willow (Salix L.) clones. New Forests, 28(1), 63-78.

Volk, T.A., Fahey, T.J. (1994). Fifty-three years of change in an upland forest in south-central New York: Growth, mortality and recruitment. Bulletin of the Torrey Botanical Club, 121(2), 140-147.

Volk, T.A. and Luzadis, V. 2009. Willow biomass production for bioenergy, biofuels and bioproducts in New York. In Renewable Energy from Forest Resources in the United States. (pp.  238-260). New York, NY: Routledge Press.

Volk, T. A., Tharakan, P. J., Abrahamson, L. P., White, E. H., & Pimentel, D. (2003). Greater potential for renewable biomass energy. Bioscience, 53(7), 620-621.

Volk, T.A., L.P. Abrahamson, E.H. White, R.F. Kopp, & C.A. Nowak.  (1999).  Producing short-rotation crops in the Northeastern United States. In Proceedings of the Second Short-Rotation Wood Crops Operations working Group Conference, Vancouver, WA, August 24-28, 1998, 7-16.

Volk, T.A., L.P. Abrahamson, E.H. White & M. Downing. (2000). Developing a Willow Biomass Crop Enterprise in the United States. In L. Christersson & L. Wright (Eds). Proceedings of the Third Meeting of IEA Bioenergy Task 17 Short-Rotation Crops for Bioenergy, Auburn, AL, Sept. 6 – 9, 1999. Oak Ridge National Laboratory, Rep. No. ORNL/TM-2000/311. 49 – 56.

Volk, T.A., B. Ballard, D.J. Robison & L.P. Abrahamson. (2000). Effect of cutting storage conditions on the survival and early growth of four willow clones. In J.G. Isebrands & J. Richardson (Compilers). 21st Session of the International Poplar Commission (IPC 2000). Poplar and Willow Culture: Meeting the Needs of Society and the Environment. USDA Forestry Service General Technical Report NC-215, 197.

 Volk, T.A., D.J. Robison & L.P. Abrahamson. (2000). Alternative methods of site preparation for willow and poplar biomass crops in the Northeastern United States. In J.G. Isebrands & J. Richardson (Compilers). 21st Session of the International Poplar Commission (IPC 2000). Poplar and Willow Culture: Meeting the Needs of Society and the Environment. USDA Forestry Service General Technical Report NC-215, 196.

Volk, T.A., B.D. Kiernan, R.F. Kopp & L.P. Abrahamson. (2001). First- and second-rotation yields of willow clones at two sites in New York State. Fifth Biomass Conference of the Americas. Sept. 17-21, 2001, Orlando, FL. 2pp.

Volk, T.A., L.P. Abrahamson & S. Edick. (2002). Outreach, education efforts and landowner participation in the Salix Consortium’s willow biomass project. In L. Christerson & L. Kuiper (eds). Proceedings of the Last Meeting of IEA Bioenergy Task 17: Short-Rotation Crops for Energy Purpose, in the Netherlands and Sweden, Dec. 11 – 16, 2000, Report 70, Swedish University of Agricultural Sciences, Uppsala, Sweden 2002, 6-12.

Volk, T.A., Verwijst, T., Tharakan, P.J., and Abrahamson, L.P. (2004). Growing energy: Assessing the sustainability of willow short-rotation woody crops. Frontiers in Ecology and the Environment. 2(8), 411-418.

Wagner, J.E., C.A. Nowak & L.P. Abrahamson. (2001). Herbicide screening trial for willow biomass crops: Applied at pre-emergence and post-emergence. In T.A. Volk, J. Ballard & L.P. Abrahamson (Compilers). Proceedings of the Third Biennial Short-Rotation Woody Crops Operations Working Group Conference, Syracuse, NY October 10-13. Syracuse, NY: SUNY-ESF, 109.

White, E.H., L.P. Abrahamson, R.L. Gambles, & L. Zsuffa.  (1988).  Experiences with willow as a wood biomass species.  Bio-Joule, 10(5), 4-7.

White, E.H., L.P. Abrahamson, R.L. Gambles, & L. Zsuffa. (1989).  Experiences with willow as a wood biomass species. In D.L. Klass (Ed.), Proceedings "Energy from Biomass and Wastes XII.”(Pp. 125-152).Chicago: Institute Of Gas Technology.

White, E.H., L.P. Abrahamson, R.F. Kopp, C.A. Nowak,  J. Sahm.  (1991).  Technological and economic aspects of biomass production from short rotation hardwood planta­tions. In Proceedings of the Fifth ABC International Biotechnology Meeting, May 13-16, 1991, Washington, DC. (Pp. 110-117).

White, E.H., L.P. Abrahamson, R.F. Kopp, C.A. Nowak, L. Zsuffa & R.L. Gambles. (1991).  Increased willow wood biomass yields by breeding, fertilization and irrigation. In D.L. Klass (Ed.), Energy From Biomass and Wastes XIV Conference, Jan. 28-Feb. 2, 1990, Orlando, FL. (Pp. 371-388). XIV-91. Chicago, IL: Institute of Gas Technology.

White, E.H., L.P. Abrahamson, R.F. Kopp, & C.A. Nowak.  (1992). Bioenergy plantations in New York - 10-year results (Abstract only). Forestry Chronicle 68(2), 221.

White, E.H., L.P. Abrahamson, R.F. Kopp, C.A. Nowak, & J. Sahm. (1992).  Integrated woody biomass systems in Eastern North America. In C.P. Mitchell, L. Sennerby-Forsse, & L. Zsuffa (Eds.), XIX IUFRO Congress, Problems and Perspec­tives of Forest Biomass Energy,  International Workshop of Project Group P1.09-00, P3.04-07 and P5.03-00, August 1990, Montreal, Canada. (Pp. 68-75). Swedish University of Agricultural Sciences, Report 48, Uppsala 1992.

White, E.H., L.P. Abrahamson, C.A. Nowak, R.F. Kopp, & L. Zsuffa.  (1992).  Integrated woody bioenergy plantations in Eastern North America. In D.L. Klass (Ed.), Energy From Biomass and Wastes XV Conference, Mar. 25-29, 1991, Washington, DC. Chicago, IL: Institute of Gas Technology.

White, E.H., L.P. Abrahamson, R.F. Kopp, & C.A. Nowak. (1993). Willow bioenergy plantation research in the Northeast. In Proceedings, First Biomass Conference of the Americas: Energy, Environment, Agriculture, and Industry, Aug. 30-Sept.2, 1993, Burlington, Vermont, Vol.I. (Pp. 199-213).

White, E.H., L.P. Abrahamson, & D.J. Robison. (1995).  Commercialization of willow bioenergy - A dedicated feedstock supply system. In Proceedings, Second Biomass Conference of the Americas: Energy, Environment, Agriculture, and Industry, Aug. 21-24, 1995, Portland, OR.  (Pp. 1534-1546).

White, E.H., L.P. Abrahamson, D.J. Robison, E.F. Neuhauser, W.H. Benjamin, & J.M. Peterson.  (1996).  Developing the willow biomass-bioenergy industry in New York: Challenges for commercializing the crop production system. In BIOENERGY ‘96 Conference Proceedings, Sept. 15-19, 1996, Nashville, TN. (Pp. 60-67).

White, E.H., E.F. Neuhauser, L.P. Abrahamson, T.A. Volk, C.A. Nowak, J.M. Peterson, E. Gray, C. Demeter & C. Lindsey. (1999).  Progress towards making willow biomass crops the fuel of the future in the northeastern United States.  In Proceedings of the 4th Biomass Conference of the Americas - Biomass: A Growth Opportunity in Green Energy and Value-added Products August 29-September 2, 1999, Oakland, CA.  Volume 1, 75-78.

White, E.H., T.A. Volk, A.J. Stipanovic, T.E. Amidon, E. Neuhauser, L.P. Abrahamson, E. Gray, C. Lindsey, J. Jarnefeld, D.J. Aneshansley, R.C Fillhart, B.D. Kiernan & S. Edick. (2001). Growing willow biomass crops for bioproducts and bioenergy in the Northeastern and Midwestern United States. Fifth Biomass Conference of the Americas. Sept. 17-21, 2001, Orlando, FL. 2pp.

Abstracts

TOP
Abrahamson, L.P., Robison, D.J., Volk, T.A., White, E.H., Neuhauser, E.F., Benjamin, W.H., Peterson, J.M. (1998). Sustainability and environmental issues associated with willow bioenergy development in New York (U.S.A.). Biomass and Bioenergy, 15(1), 17-22.

Abstract
Biomass-for-bioenergy cropping and production systems based on willow (and poplar) planted and managed at high densities and short (3-4 year) coppice harvest cycles, providing fuel for co-firing with Coal (or other types of energy conversion) must be ecologically and environmentally sustainable to be commercially successful. Current knowledge arid ongoing research and development indicate that the production and utilization systems involved are environmentally and ecologically sustainable. Therefore two primary constraints to commercialization are being met. The remaining constraint is economic viability based on cost of production and use, the value of environmental externalities (such as atmospheric emissions), and potential government/public policy actions to promote this system of providing a locally produced and renewable farm Crop and fuel. The environmental and ecological benefits of the system should act as a catalyst for developments needed to overcome the economic constraints of the system.

Biomass-for-bioenergy cropping and production systems based on willow (and poplar) planted and managed at high densities and short (3-4 year) coppice harvest cycles, providing fuel for co-firing with coal (or other types of energy conversion) must be ecologically and environmentally sustainable to be commercially successful. Current knowledge and ongoing research and development indicate that the production and utilization systems involved are environmentally and ecologically sustainable. Therefore two primary constraints to commercialization are being met. The remaining constraint is economic viability based on cost of production and use, the value of environmental externalities (such as atmospheric emissions), and potential government/public policy actions to promote this system of providing a locally produced and renewable farm crop and fuel. The environmental and ecological benefits of the system should act as a catalyst for developments needed to overcome the economic constraints of the system.

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Abrahamson, L. P., White, E. H., Nowak, C. A., Briggs, R. D., & Robison, D. J. (1990). Evaluating hybrid poplar clonal growth potential in a three-year-old genetic selection field trial. Biomass, 21(2), 101-114.

Abstract
Survival, growth, and insect and disease damage of 54 hybrid poplar clones were compared in a three-year-old genetic selection field trial located in the St Lawrence River Valley, near Massena, New York, USA. Clones were grouped into growth potential classes using cluster analysis and indices of total growth and canker severity. Statistical significance of growth potential classes was tested using discriminant analysis. Seven of the 54 clones examined (DN16, NM6, NE17, D51, DN38, DN55 and NE21) were recommended for additional evaluations in larger scale clone-site trials. The technique presented in this report facilitates hardwood clone performance evaluation for a wide variety of desired products.

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Abrahamson, L. P., White, E. H., Nowak, C. A., & Kopp, R. F. (1990). Yield potential of willow in New York State. evidence from two years research in an ultrashort-rotation system. Energy from Biomass and Wastes XIII, New Orleans, LA, USA. 261-174.

Abstract
A recently developed concept for maximizing wood biomass production for energy is the ultrashort-rotation, or 'wood grass', system. While researchers in Europe have shown that 20 to 40 oven dry (o.d.) t ha-1 yr-1 can be attained using willow in short-rotation intensive culture systems, ultrashort-rotation plantations of willow are expected to produce even higher yields on a 1- or 2-year harvest schedule. A clone-site trial of phenotypically superior willow represents one of the first efforts in the United States to test willow for use in wood grass systems. It is shown that Salix viminalis, S. hastata L. and S. purpurea clones, all shrub-type willows, produced the most biomass during both years.

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Adegbidi, H.G., Briggs, R.D., Volk, T.A., White, E.H., Abrahamson, L.P. (2003). Effect of organic amendments and slow-release nitrogen fertilizer on willow biomass production and soil chemical characteristics. Biomass and Bioenergy, 25(4), 389-398.

Abstract
Lime-stabilized sewage sludge and composted poultry manure, at a rate of 250 m3 ha-1 each, and slow-release N fertilizer (Scott's Osmocote) at 100, 200 and 300 kg N ha-1, were applied to plots of willow biomass crops during the first season of a three-year growth cycle. Stem biomass production was measured annually and soil chemical characteristics were assessed at the end of the growth cycle. Average annual stem biomass production was 8-11 Mg ha-1 in slow-release N fertilized plots corresponding to a yield increase of 7-33% relative to control plots. In organically amended plots, annual stem biomass production increased by 30-38% relative to control plots. The study suggests that organically amended willows grew at a slightly faster rate than slow-release N fertilized willows. Statistically, the relationship between slow-release N application rate and stem biomass production was not highly significant; applications of slow-release N in excess of 100 kg N ha-1 provided no additional yield benefits. Differences in soil characteristics were most strongly expressed in surface soil. The pH at 0-10 cm depth was 1 and 2 units higher on lime-stabilized sludge and composted poultry manure plots, respectively. Concentrations of soil K, P and Mg were dramatically higher in the composted poultry manure soils. The highest soil organic matter and N levels were observed in the surface horizons of organically amended soils. Utilization of organic residuals increases biomass production, provides beneficial use for wastes, reducing production costs and contributing to the sustainability of biomass production systems. © 2003 Elsevier Ltd. All rights reserved.

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Adegbidi, H.G., Volk, T.A., White, E.H., Abrahamson, L.P., Briggs, R.D., Bickelhaupt, D.H. (2001). Biomass and nutrient removal by willow clones in experimental bioenergy plantations in New York State. Biomass and Bioenergy, 20(6), 399-411.

Abstract
The development of short-rotation intensive cultural (SRIC) willow systems as a source of bioenergy and bioproducts is growing in the northeastern and midwestern United States. Important data for sustainable management such as nutrient removal and nutrient use efficiency in willow bioenergy plantations is lacking. This study reports wood biomass production, annual removal of nutrients, and nutrient use efficiency in experimental plantings of SRIC willow and poplar at Tully, New York. Effects of clone, fertilization, irrigation, planting density, and harvest cycle were analyzed. Annual biomass production of 15-22 dry Mg/ha removed 75-86, 10-11, 27-32, 52-79 and 4-5 kg/ha/year of N, P, K, Ca and Mg; respectively. For all the variables studied, the responses depended on clone. Fertilization and irrigation increased rates of nutrient removal by means of increased biomass production. Unlike planting density, harvest cycle significantly affected rates of nutrient removal and nutrient use efficiency. For clone SV1 (Salix dasyclados), an irrigated and fertilized planting with a density of 36,960 trees/ha harvested on a 3-year rotation had the highest biomass production and nutrient use efficiency, and the lowest rates of nutrient removal. The annual harvest cycle had the lowest nutrient use efficiency and the highest annual removal of nutrients suggesting that this choice would be most appropriate for biomass crops that are to be used as buffer strips to manage nutrient runoff from agricultural fields. An appropriate choice of clone, planting density, and harvest cycle could tailor the rates of nutrient removal and nutrient use efficiency to match the objective of the planting. © 2001 Elsevier Science Ltd.

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Arevalo, C.B.M., Drew, A.P., Volk, T.A. (2005). The effect of common Dutch white clover (trifolium repens L.), as a green manure, on biomass production, allometric growth and foliar nitrogen of two willow clones. Biomass and Bioenergy, 29(1), 22-31.

Abstract
There is potential for soil erosion and non-point source pollution during the establishment of short-rotation woody crops (SRWC) in northern climates as a limited amount of cover remains on soils from the time of site preparation until SRWC occupies the site early in the second growing season. To counteract these impacts, green manure crops may be established and turned under early in the growing season. The effects of a green manure crop, white clover (Trifolium repens L.), on growth rates, biomass allocation, and foliar nitrogen concentrations of two willow clones (Salix sachalinensis and S. discolor) were compared in a field experiment to nitrogen fertilizer and control treatments over a period of 4 months. Willows were grown in rooting envelopes and harvested four times during the growing season to assess differences in allometric growth. White clover was found to increase the foliar nitrogen concentration of willow without compromising aboveground biomass. Fertilizer induced a 24% increase in total biomass of willow relative to the control. The rate of biomass allocation aboveground was greater relative to belowground under all treatments, and allometric coefficients were greater than 1.0. The differences in nitrogen uptake patterns and nitrogen use efficiencies of willow corresponded to the differences in biomass and foliar nitrogen concentrations between clones. © 2005 Elsevier Ltd. All rights reserved.

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Arevalo, C.B.M., Volk, T.A., Bevilacqua, E., Abrahamson, L.P. (2007). Development and validation of aboveground biomass estimations for four Salix clones in central New York. Biomass and Bioenergy, 31(1), 1-12.

Abstract
Commercial and research scale plantings of short-rotation woody crops require reliable and efficient estimations of biomass yield before time of harvest. Biomass equations currently exist but the accuracy and efficiency of estimation procedures at the level of specificity needs to be quantified for clones being used in North America. Diameter-based allometric equations for aboveground biomass for four clones of willow (Salix discolor, Salix alba, Salix dasyclados, and Salix sachalinensis), between two sites (Canastota and Tully, NY), and across four years (1998-2001), were developed using ordinary least-squares regression (OLSR) on log-transformed variables, weighted least squares regression (WLSR) on log-transformed variables, and nonlinear regression (NLR) methods and validated using independent data sets. Biomass estimations derived from clone, age, and site (Specific) using OLSR equations had highest R2 and lowest percent bias (<2.3%) allowing for accurate estimations of standing biomass. Values for specific equations using WLSR were similar, but bias was higher for NLR (0.7-12.5%). However, the amount of time and effort required to develop specific equations, is large and in many situations prohibitive. Biomass estimates derived from clone and age, regardless of site (Intermediate), resulted in small increases in prediction error and a small increase in percent bias using OLSR (<0.4%) and WLSR (<1.7%). The increase in percent bias was larger (1.1-5.7%) for NLR equations. Intermediate models correspond to the loss of only a small amount of accuracy while gaining more efficiency in estimating standing biomass. Estimates of biomass derived from clone alone (general) equations, considering neither age nor site, had the weakest prediction abilities that may lead to large errors for biomass estimations using OLSR (7.0-9.5%), WLSR (1.1-21.7%) or NLR (31.9-143.4%). © 2006 Elsevier Ltd. All rights reserved.

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Buchholz, T., Luzadis, V.A., Volk, T.A. (2009). Sustainability criteria for bioenergy systems: Results from an expert survey. Journal of Cleaner Production,17(Supplement 1), S86-S98.

Abstract
Environmental impacts associated with the use of fossil fuels, rising prices, potential limitations in supply and concerns about regional and national security are driving the development and use of biomass for bioenergy, biofuels and bioproducts. However, the use of biomass does not automatically imply that its production, conversion and use are sustainable. In order to operationalize sustainability assessments of biomass systems, it is crucial to identify critical criteria, but keep their number and measurement at a manageable level. The selection of these criteria can vary depending on individual's expertise, geographical region where they work, and spatial scale they are focused on. No clear consensus has yet emerged on what experts consider as critical indicators of sustainability. Objectives of this paper were to analyze how key experts perceive the 35 sustainability criteria for bioenergy found in emerging sustainability assessment frameworks and to identify levels of agreement and uncertainty. Experts were asked to rate the criteria for attributes of relevance, practicality, reliability, and importance. Perceptions of the importance of the 35 criteria varied among the experts surveyed. Only two criteria, energy balance and greenhouse gas balance, were perceived as critical by more than half of the respondents. Social criteria and locally applied criteria were generally ranked low for all four attributes. Seven of the 12 criteria scored as most important focused on environmental issues, four were social and only one was economic. Of the 12 most important criteria, seven were ranked low in practicality and reliability indicating that mechanisms to assess a number of important criteria need to be developed. The spatial scale the experts worked at and their profession explained most of the differences in importance ranking between experts, while regional focus had minimal effect. Criteria that were ranked low for importance were characterized by a lack of consensus, suggesting the need for further debate regarding their inclusion in sustainability assessments. Outcomes of the survey provide a foundation for further discussions and development of sustainability assessments for bioenergy systems and may also provide a basis for assessing individual bioenergy projects within their specific geographic, ecological, societal, and technological context and scale. © 2009 Elsevier Ltd. All rights reserved.

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Buchholz, T., Rametsteiner, E., Volk, T.A., Luzadis, V.A. (2009). Multi criteria analysis for bioenergy systems assessments. Energy Policy, 37(2), 484-495.

Abstract
Sustainable bioenergy systems are, by definition, embedded in social, economic, and environmental contexts and depend on support of many stakeholders with different perspectives. The resulting complexity constitutes a major barrier to the implementation of bioenergy projects. The goal of this paper is to evaluate the potential of Multi Criteria Analysis (MCA) to facilitate the design and implementation of sustainable bioenergy projects. Four MCA tools (Super Decisions, DecideIT, Decision Lab, NAIADE) are reviewed for their suitability to assess sustainability of bioenergy systems with a special focus on multi-stakeholder inclusion. The MCA tools are applied using data from a multi-stakeholder bioenergy case study in Uganda. Although contributing to only a part of a comprehensive decision process, MCA can assist in overcoming implementation barriers by (i) structuring the problem, (ii) assisting in the identification of the least robust and/or most uncertain components in bioenergy systems and (iii) integrating stakeholders into the decision process. Applying the four MCA tools to a Ugandan case study resulted in a large variability in outcomes. However, social criteria were consistently identified by all tools as being decisive in making a bioelectricity project viable. © 2008 Elsevier Ltd. All rights reserved.

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Buchholz, T.S., Volk, T.A., Luzadis, V.A. (2007). A participatory systems approach to modeling social, economic, and ecological components of bioenergy. Energy Policy, 35(12), 6084-6094.

Abstract
Availability of and access to useful energy is a crucial factor for maintaining and improving human well-being. Looming scarcities and increasing awareness of environmental, economic, and social impacts of conventional sources of non-renewable energy have focused attention on renewable energy sources, including biomass. The complex interactions of social, economic, and ecological factors among the bioenergy system components of feedstock supply, conversion technology, and energy allocation have been a major obstacle to the broader development of bioenergy systems. For widespread implementation of bioenergy to occur there is a need for an integrated approach to model the social, economic, and ecological interactions associated with bioenergy. Such models can serve as a planning and evaluation tool to help decide when, where, and how bioenergy systems can contribute to development. One approach to integrated modeling is by assessing the sustainability of a bioenergy system. The evolving nature of sustainability can be described by an adaptive systems approach using general systems principles. Discussing these principles reveals that participation of stakeholders in all components of a bioenergy system is a crucial factor for sustainability. Multi-criteria analysis (MCA) is an effective tool to implement this approach. This approach would enable decision-makers to evaluate bioenergy systems for sustainability in a participatory, transparent, timely, and informed manner.

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Cameron, K., R.F. Kopp, I. Philips, T.A. Volk, L.P. Abrahamson and L.B. Smart. 2008. Quantitative genetics of traits indicative of biomass production and heterosis in 34 full-sib F1 Salix eriocephala families. BioEnergy Research.1(1), 80-90.

Abstract
This project examined the heritability of traits that affect biomass production of Salix eriocephala, a shrub willow native to North America and an essential species in the breeding of bioenergy crop varieties. Using an incomplete factorial design, seven females and eight males were crossed to produce 34 full-sib F1 families. Five to 12 entries per family were planted in four-plant plots in a randomized complete block design on two sites. Melampsora rust incidence was scored in the fall of the first growing season (prior to coppice). Height of the tallest stem, cross-sectional stem area per stool, and number of stems per stool were recorded in the winter after the first growing season post-coppice. Plants were harvested 3 years post-coppice and biomass yield was determined. A large percentage of the total variance was additive for all of the traits studied and heritability estimates were low to moderate, suggesting that phenotypic expression of these traits is predictable and can be improved through breeding. Based on yield 3 years after coppice, 29 of the 34 families displayed midparent heterosis, ranging from 1–115%, for the composite trait—biomass yield, strongly indicating that offspring often perform better than their parents in this population. This study will assist in selecting parents which may produce superior progeny in the breeding program.

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Castellano, P.J., Volk, T.A., Herrington, L.P. (2009). Estimates of technically available woody biomass feedstock from natural forests and willow biomass crops for two locations in New York State. Biomass and Bioenergy, 33(3), 393-406.

Abstract
A Geographic Information System (GIS) was used to estimate the technically available woody biomass from forests and willow biomass crops within a 40 km radius of Syracuse and Tupper Lake, NY. Land cover and land use data were used to identify the available land base and restrictions were applied for slope, parcel size and designated wetlands. Approximately 222,984 oven-dry tonnes (odt) of forest biomass are technically available annually around Syracuse, from 165,848 hectares (ha) of timberland. There are 67,880 ha of agricultural land technically available for growing willow biomass crops, which could produce 38,181 odt yr-1 if 5% of this land was used and yields were 11.25 odt ha-1 yr-1. There are approximately 215,300 odt of forest biomass technically available annually around Tupper Lake from 211,500 ha of timberland. There are 781 ha of technically available agricultural land in this area so willow biomass production would be minimal. While these two areas have different land cover and land use characteristics, both have the potential to produce significant amounts of woody biomass. © 2008 Elsevier Ltd. All rights reserved.

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Clinch, R.L., Thevathasan, N.V., Gordon, A.M., Volk, T.A., Sidders, D. (2009). Biophysical interactions in a short rotation willow intercropping system in southern Ontario, Canada. Agriculture, Ecosystems and Environment, 131(1-2), 61-69.

Abstract
Recently, there has been interest in shifting to carbon-neutral sources of energy, including bioenergy from short rotation woody crops. This study looked at the growth and yields of short rotation willow in an agroforestry intercropping system compared to a conventional single variety plot system used as a control. Three willow clones (Salix dasyclados SV1, Salix miyabeana SX67 and Salix purpurea 9882-41) were established in each field setup, where in the agroforestry field willow plots were located between 15 m wide rows of 20-year-old mixed tree species. Differences in photosynthetic photon flux density (PPFD), soil temperature, soil moisture and soil/foliar nitrogen between the two field setups were investigated from 2006 to 2007. Willow yields were significantly higher in the agroforestry fields during both years of the study, with 0.8 and 0.5 odt ha-1 for the agroforestry and control fields, respectively, in 2006, and 3.0 and 1.1 odt ha-1 respectively, in 2007. There were opposite trends in clonal yields between the two field setups in 2006, but in 2007, clonal yields were in the same order across fields with averages of 2.8, 2.2 and 1.2 odt ha-1 for SV1, SX67 and 9882-41, respectively. Daily average photosynthetic photon flux density was 210 μmol m-2 s-1 (16%) lower in the agroforestry system, and PPFD was correlated with soil temperatures that were on average 0.4 °C and 2.7 °C lower in the agroforestry field in 2006 and 2007, respectively (r = 0.82 and 0.93). Soil temperatures were negatively correlated with soil moisture levels that were on average 1.4% and 1.9% higher in the agroforestry field in 2006 and 2007, respectively (r = -0.54 and -0.41), and soil moisture content was positively correlated with willow yields (r = 0.49 and 0.72). There was less soil available nitrogen in the agroforestry field, but no difference in foliar nitrogen between fields. An experiment excluding root competition in the top 1 m of soil between intercropped trees and willows in the agroforestry field found no significant competition for soil moisture or nitrogen in the first two years of growth. Results of this study suggest that moderate shading in an intercropping setup can result in a buffering effect on microclimate conditions, where there is less variation in soil moisture content and soil temperature across a range of weather conditions. © 2009 Elsevier B.V. All rights reserved.

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Downing, M., Volk, T.A., Schmidt, D.A. (2005). Development of new generation cooperatives in agriculture for renewable energy research, development, and demonstration projects. Biomass and Bioenergy, 28(5), 425-434.

Abstract
Any of several business structures may be used to operate a farm enterprise. Models have been developed showing advantages and disadvantages of sole proprietorships, partnerships, and corporations when applied as farm enterprises. In recent years, the farm cooperative business structure has taken on a different complexion, especially when faced with new crops and uses, mixed, multiple, and international markets, and cross-cutting market sectors. These new generation cooperatives have played a particularly strong role in developing renewable energy and agricultural enterprises, especially in the face of proposed new crop rotations, inclusion of perennial crops in these rotations, and different management scenarios based on agro-forestry principles. In this paper, we define conditions under which the farm cooperative is an appropriate business enterprise structure, and review and update the status of four of these new generation cooperative business structures in Minnesota, New York, and Iowa. We assess the status of development of these cooperatives and the market conditions needed for the agriculture, energy, and environmental sectors that comprise these cooperatives. © 2004 Elsevier Ltd. All rights reserved.

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Fain, J.J., Volk, T.A., Fahey, T.J. (1994). Fifty years of change in an upland forest in south-central New York: General patterns. Bulletin of the Torrey Botanical Club, 121(2), 130-139.

Abstract
Long-term changes in the composition and structure of an upland hardwood forest in south-central New York were quantified by resurvey of 22 permanent plots originally established in 1935. In 1935 most of the forest consisted of stands recovering from disturbance by logging in the late 19th century, and most of the plots underwent timber stand improvement in 1934 that reduced basal area by an average of about one-third. Average basal area nearly doubled during the 50 year period, and basal area of the individual plots converged from widely disparate values in 1935 to about 32 m2/ha in 1985. Size structure of the forest changed markedly over the 50-year period reflecting high recruitment of the shade tolerant species-sugar maple, beech, hemlock-as well as a significant decline in density of suppressed sub-canopy trees (10-20 cm DBH) mostly as a result of mortality. Although basal area of the mid-tolerant species-white ash, red maple, basswood-remained high, recruitment of these species was limited and in the continuing absence of large scale disturbance the forest appears to be moving towards a composition dominated by the highly shade tolerant species.

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Heller, M.C., Keoleian, G.A., Mann, M.K., Volk, T.A. (2004). Life cycle energy and environmental benefits of generating electricity from willow biomass. Renewable Energy, 29(7), 1023-1042.

Abstract
Biomass is a key renewable energy source expected to play an important role in US electricity production under stricter emission regulations and renewable portfolio standards. Willow energy crops are being developed in the northeast US as a fuel source for increasing biomass energy and bioproduct demands. A life cycle inventory is presented that characterizes the full cradle-to-grave energy and environmental performance of willow biomass-to-electricity. A willow biomass production model is developed using demonstration-scale field experience from New York. Scenarios are presented that mimic anticipated co-firing operations, including supplemental use of wood residues, at an existing coal-fired generating facility. At a co-firing rate of 10% biomass, the system net energy ratio (electricity delivered divided by total fossil fuel consumed) increases by 8.9% and net global warming potential decreases by 7-10%. Net SO2 emissions are reduced by 9.5% and a significant reduction in NOx emissions is expected. In addition, we estimate system performance of using willow biomass in dedicated biomass gasification and direct-fired generating facilities and demonstrate that the pollution avoided (relative to the current electricity grid) is comparable to other renewables such as PV and wind. © 2003 Elsevier Ltd. All rights reserved.

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Heller, M.C., Keoleian, G.A., Volk, T.A. (2003). Life cycle assessment of a willow bioenergy cropping system. Biomass and Bioenergy, 25(2), 147-165.

Abstract
The environmental performance of willow biomass crop production systems in New York (NY) is analyzed using life cycle assessment (LCA) methodology. The base-case, which represents current practices in NY, produces 55 units of biomass energy per unit of fossil energy consumed over the biomass crop's 23-year lifetime. Inorganic nitrogen fertilizer inputs have a strong influence on overall system performance, accounting for 37% of the non-renewable fossil energy input into the system. Net energy ratio varies from 58 to below 40 as a function of fertilizer application rate, but application rate also has implications on the system nutrient balance. Substituting inorganic N fertilizer with sewage sludge biosolids increases the net energy ratio of the willow biomass crop production system by more than 40%. While CO2 emitted in combusting dedicated biomass is balanced by CO2 adsorbed in the growing biomass, production processes contribute to the system's net global warming potential. Taking into account direct and indirect fuel use, N2O emissions from applied fertilizer and leaf litter, and carbon sequestration in below ground biomass and soil carbon, the net greenhouse gas emissions total 0.68 g CO2 eq. MJbiomass produced-1. Site specific parameters such as soil carbon sequestration could easily offset these emissions resulting in a net reduction of greenhouse gases. Assuming reasonable biomass transportation distance and energy conversion efficiencies, this study implies that generating electricity from willow biomass crops could produce 11 units of electricity per unit of fossil energy consumed. Results from the LCA support the assertion that willow biomass crops are sustainable from an energy balance perspective and contribute additional environmental benefits. © 2003 Elsevier Science Ltd. All rights reserved.

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Keoleian, G.A., Volk, T.A. (2005). Renewable energy from willow biomass crops: Life cycle energy, environmental and economic performance. Critical Reviews in Plant Sciences, 24(5-6), 385-406.

Abstract
Short-rotation woody crops (SRWC) along with other woody biomass feedstocks will play a significant role in a more secure and sustainable energy future for the United States and around the world. In temperate regions, shrub willows are being developed as a SRWC because of their potential for high biomass production in short time periods, ease of vegetative propagation, broad genetic base, and ability to resprout after multiple harvests. Understanding and working with willow's biology is important for the agricultural and economic success of the system. The energy, environmental, and economic performance of willow biomass production and conversion to electricity is evaluated using life cycle modeling methods. The net energy ratio (electricity generated/life cycle fossil fuel consumed) for willow ranges from 10 to 13 for direct firing and gasification processes. Reductions of 70 to 98 percent (compared to U.S. grid generated electricity) in greenhouse gas emissions as well as NOx, SO2, and particulate emissions are achieved. Despite willow's multiple environmental and rural development benefits, its high cost of production has limited deployment. Costs will be lowered by significant improvements in yields and production efficiency and by valuing the system's environmental and rural development benefits. Policies like the Conservation Reserve Program (CRP), federal biomass tax credits and renewable portfolio standards will make willow cost competitive in the near term. The avoided air pollution from the substitution of willow for conventional fossil fuel generated electricity has an estimated damage cost of $0.02 to $0.06 kWh-1. The land intensity of about 4.9 × 10-5 ha-yr/kWh is greater than other renewable energy sources. This may be considered the most significant limitation of willow, but unlike other biomass crops such as corn it can be cultivated on the millions of hectares of marginal agricultural lands, improving site conditions, soil quality and landscape diversity. A clear advantage of willow biomass compared to other renewables is that it is a stock resource whereas wind and PV are intermittent. With only 6 percent of the current U.S. energy consumption met by renewable sources the accelerated development of willow biomass and other renewable energy sources is critical to address concerns of energy security and environmental impacts associated with fossil fuels. Copyright © Taylor & Francis Inc.

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Kopp, R. F., Abrahamson, L. P., White, E. H., Burns, K. F., & Nowak, C. A. (1997). Cutting cycle and spacing effects on biomass production by a willow clone in New York. Biomass and Bioenergy, 12(5), 313-319. doi:10.1016/S0961-9534(96)00077-3

Abstract
An experiment was established in central New York State in 1990 to determine cutting cycle and spacing effects on willow biomass production. Cutting cycles were annual, biennial and triennial, and spacings were 0.3 x 0.3.0.3 x 0.9, and 0.6 x 1.1 m; biomass production and survival by willow clone SV1 (Salix dasyclados) were measured. Beginning in the second growing season, trees were fertilized with N, P and K, and irrigated. Willow clone SV1 harvested triennially with 0.3 x 0.9 m spacing yielded 71.3 odt ha-1 an average annual production of 23.8 odt ha-1 year-1. Spacing of 0.3 x 0.9 m yielded the most biomass, but spacing differences were not significant for biomass production. Triennial harvesting was significantly more productive than cumulative production after 3 years with annual harvesting (64.5 versus 39.2 odt ha-1). Cumulative production from two biennial harvests was significantly larger than cumulative production from four annual harvests (64.3 versus 50.1 odt ha-1). Tree survival was similar among cutting cycles after five growing seasons, averaging 75%. Statistically significant differences in survival were detected among spacings, averaging 88, 80 and 57% at 0.60 by 1.1, 0.3 x 0.9 and 0.3 x 0.3 m spacings, respectively during 1994.

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Kopp, R.F., E.H. White, L.P. Abrahamson, C.A. Nowak, & K.F. Burns. (1993). Willow biomass trials in central New York State.  Biomass and Bioenergy 5(2), 179-187.

Abstract
An experiment was established in central New York State in 1987 to determine the biomass production potential of Salix using ultrashort-rotation intensive culture with annual harvests. Half of the plots were fertilized annually with N, P, and K, and all plots were irrigated during their third, fourth, and fifth growing seasons. The most productive clone, willow clone SV l, yielded 16 o.d. t ha−1 yr−1 during the fifth growing season. Fertilization significantly increased the rate at which clones reached their annual maximum biomass production, but the annual maximum level ultimately achieved was the same with or without fertilization. Total five year biomass production was increased by fertilization for specific clones. Large clonal variation in biomass production potential and survival was observed, along with significant clone-by-fertilizer interaction.

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Kopp, R. F., Abrahamson, L. P., White, E. H., Nowak, C. A., Zsuffa, L., & Burns, K. F. (1996). Woodgrass spacing and fertilization effects on wood biomass production by a willow clone. Biomass and Bioenergy, 11(6), 451-457. doi:10.1016/S0961-9534(96)00055-4

Abstract
An experiment was established in central New York State in 1987 to determine the effect of spacing and fertilization on wood biomass production of one willow clone grown with intensive culture and harvested annually. Spacings were 0.15 x 0.15, 0.30 x 0.30 and 0.46 x 0.46 m. Half of the plots were fertilized annually with N, P and K elemental rates of 336, 112 and 224 kg ha-1. All plots were irrigated during their third, fourth and fifth growing seasons. Fertilizer increased the rate at which trees attained their maximum production, but their maximum estimated production level was reduced compared with non-fertilized trees. Trees responded positively to fertilizer during the first three growing seasons. Trees spaced at 0.46 x 0.46 and 0.30 x 0.30 m had significantly higher maximum estimated production levels than trees spaced at 0.15 x 0.15 m. During the fourth and fifth growing seasons, trees spaced at 0.46 x 0.46 m were most productive, but cumulative production after five successive annual harvests was highest by trees spaced at 0,30 x 0.30 m. Survival remained high (83% averaging spacing and fertilizer treatments) after five harvests and was not affected by spacing or fertilization.

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Kopp, R.F., Abrahamson, L.P., White, E.H., Volk, T.A., Nowak, C.A., Fillhart, R.C. (2001). Willow biomass production during ten successive annual harvests. Biomass and Bioenergy, 20(1), 1-7.

Abstract
Five willow clones and one hybrid poplar clone were planted during 1987 at 0.3 × 0.3m spacing and harvested annually for 10 years. Half of the trees were fertilized annually with N, P and K and all trees were irrigated beginning in the third growing season. Annual biomass production fit the logistic growth curve well for four of the clones with r2 values ranging from 0.91 to 0.54, suggesting that well-adapted willow clones can be consistently productive for at least 10 years with annual harvesting. Fertilizer did not increase the maximum biomass production level attained, but it reduced the time required to reach maximum production by 1 year. The correlation between annual biomass production and the number of growing degree days during years 4-10 was high, ranging from 0.95 to 0.66. © 2001 Elsevier Science Ltd.

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Kopp, R. F., Castello, J. D., & Abrahamson, L. P. (1999). Viruses in salix grown for bioenergy. European Journal of Forest Pathology, 29(2), 117-122.

Abstract
A study was completed to determine if willows propagated vegetatively for bioenergy in New York State were infected by viruses. Unrooted, dormant cuttings from 10 willow clones were planted in a greenhouse. Four months later the young foliage and roots were tested for tomato mosaic tobamovirus, tobacco necrosis necrovirus (TNV), and brome mosaic bromovirus by double-antibody sandwich enzyme-linked immunosorbent assay. All three viruses were detected in the roots of some plants, but rarely in foliage. Every clone was infected with at least one virus. Tobacco mosaic virus and TNV were also transmitted to Chenopodium quinoa from extracts of roots collected from field-grown willows. Imported willow material may be virus-infected.

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Kopp, R. F., Maynard, C. A., De Niella, P. R., Smart, L. B., & Abrahamson, L. P. (2002). Collection and storage of pollen from Salix (Salicaceae). American Journal of Botany, 89(2), 248-252.

Abstract
Genetic improvement of willows through traditional breeding can be facilitated by pollen collection and storage so that female flower receptivity need not be synchronized with pollen shed for breeding. Two experiments were completed to test the effectiveness of various organic solvents for willow pollen collection. In the first experiment, seven pollen collection treatments and an untreated control were tested with two willow clones. The other experiment tested three treatments that showed promise in the initial experiment and an untreated control with eight willow clones. Toluene and carbon tetrachloride were effective for pollen extraction, with average pollen germination percentages that were > 15%, but both chemicals reduced pollen viability by 10-20% compared with an untreated control based on in vitro germination tests. Pollen extracted with carbon tetrachloride or toluene was successfully used in controlled pollination, and > 100 new families were produced with this technique. Pollen viability remained high after 18 mo of storage at -20°C. Based on our results, toluene is the preferred solvent for future willow pollen extractions because it is as effective as carbon tetrachloride, is not a known carcinogen, and is less expensive.

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Kopp, R. F., Smart, L. B., Maynard, C. A., Isebrands, J. G., Tuskan, G. A., & Abrahamson, L. P. (2001). The development of improved willow clones for eastern North America. Forestry Chronicle, 77(2), 287-292.

Abstract
Efforts aimed at genetic improvement of Salix are increasing in North America. Most of these are directed towards developing improved clones for biomass production, phytoremediation, nutrient filters, and stream bank stabilization in the Northeast and North-central United States. Native species are of primary interest, but a small number of clones containing non-native germplasm are also being used in the breeding program to provide valuable traits. Parent combinations for controlled crosses are being selected with the hope of maximizing the probability of producing clones exhibiting heterosis for traits of interest, such as rapid early growth, pest resistance, general adaptability, etc. The present strategy is to test as many parent clone combinations as possible, and then repeat the most promising crosses to produce large families from which the best clones will be selected for further testing. Molecular fingerprinting technology will be applied to accelerate the rate of improvement. National and international cooperation would facilitate regional clone development and promotion of willow as a bioenergy crop.

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Kopp, R. F., Smart, L. B., Maynard, C. A., Tuskan, G. A., & Abrahamson, L. P. (2002). Predicting within-family variability in juvenile height growth of Salix based upon similarity among parental AFLP fingerprints. Theoretical and Applied Genetics, 105(1), 106-112. doi:10.1007/s00122-001-0855-3

Abstract
Willow is being developed as a crop for biomass plantations in the Northeast and North-central United States, but has only recently been the subject of controlled breeding to generate improved genotypes. Maximizing variability among progeny within full-sib families produced by controlled pollination may increase the probability of producing willow clones exhibiting desirable extreme phenotypes. Yet, predicting combinations of parents yielding highly variable progeny is not currently possible. Controlled pollinations were completed among 15 Salix eriocephala clones and the resulting progeny were vegetatively propagated and planted in a greenhouse progeny test. Heights of rooted cuttings were measured after 4 months of growth. Genetic similarity among parents was estimated based on 77 polymorphic AFLP bands. Strong negative correlation (r = -0.88) was detected between mean female-parent similarity indices and the standard deviation of height among half-sib progeny from those females. Parent combinations that had relatively low similarity indices tended to produce progeny that had greater variability in height. This negative relationship suggests that AFLP fingerprints of S. eriocephala parents may be useful for predicting parent combinations that will yield families with large variability.

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Kuzovkina, Y.A., Volk, T.A. (2009). The characterization of willow (Salix L.) varieties for use in ecological engineering applications: Co-ordination of structure, function and autecology. Ecological Engineering, 35(8), 1178-1189.

Abstract
The rapid development of innovative and highly specialized ecotechnologies targeting site-specific problems and pollutants requires precisely tailored designs. The proper selection of remedial plant genotypes that possess the correct structure and function to effectively address a specific problem is a vital step in the design of ecological engineering applications because numerous essential traits must be evaluated to maximize the effectiveness of each installation. Knowledge about the biology of willow species from decades of research as a perennial biomass crop has recently been applied to resolving an array of environmental and ecological problems. Here, essential characteristics of Salix varieties that are pertinent to ecological engineering are described and related to particular ecotechnologies. We identified thirty-six agronomical, physiological, and ecological attributes of willow that provide a framework for species selection and assist in the identification of site-specific functional types of willows for land reclamation, phytoremediation, bioengineering, and agroforestry. © 2009 Elsevier B.V. All rights reserved.

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Lo, M.H., Abrahamson, L.P., White, E.H., & Manion, P.D. (1995). Early measures of basal area and canker disease predict growth-potential of some hybrid poplar clones. Canadian Journal of Forest Research 25(7), 1113-1118.

Abstract
Differences in percent survival, canker disease rating, and basal area (m(2)-. ha(-1)) were quantified for a plantation of 54 hybrid poplar clones in northern New York at ages 3 and 9 years to test the hypothesis that early growth and canker incidence indicate future growth. Differences in growth and canker severity between clones with similar parentage were assessed. Five of the seven clones, which exhibited high basal areas and low disease ratings at 3 years of age, maintained their growth potential at 9 years of age. Four of the five clones, which had 0% survival at 9 years of age, had low basal areas at 3 years of age. The growth potential of the remaining clones was not accurately predicted based on early measures of growth and disease incidence. Variation in basal area and canker rating among clones within the same parentage group made it impossible to use parentage as a predictor of growth potential. Correlations among canker rating and basal area and percent survival increased over time, suggesting that impacts of canker disease became more significant with age. Septoria musiva Peck was suspected to be the primary cause of stem cankers, but isolations revealed the presence of many fungi.

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Lo, M. H., & Abrahamson, L. P. (1996). Principal component analysis to evaluate the relative performance of nine year old hybrid poplar clones. Biomass and Bioenergy, 10(1), 1-6.

Abstract
Previous studies have identified particular hybrid poplar parentage lines associated with a certain level of growth or disease resistance. This study used principal component analysis (PCA) to evaluate the relative performance of 54 hybrid poplar clones based on nine year old measures of growth and canker disease. Growth was characterized by percentage survival and total basal area per clone, while disease was characterized by the number of cankers per living tree and canker appearance. The first principal component which accounted for 85% of the variation in the data set was used to rank the clones. In general, clones which exhibited high growth and low disease measures were ranked at the top of the list. One exception, clone GA88 (ranked near the top), was uncankered and despite having low survival, produced a relatively high basal area. PCA provided an ordering of clones based upon growth and disease which can be used to select clones for larger scale testing. Future applications of multivariate techniques can incorporate additional variables considered important for biomass, wood pulp, or veneer production. © 1996 Elsevier Science Ltd.

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Minor, M.A., Volk, T.A., Norton, R.A. (2004). Effects of site preparation techniques on communities of soil mites (acari: Oribatida, acari: Gamasida) under short-rotation forestry plantings in New York, USA. Applied Soil Ecology, 25(3), 181-192.

Abstract
To address the question of how production of woody biomass crops on retired agricultural land will affect soil biodiversity, we investigated the effects of site preparation techniques associated with production of willow (Salix sp.) on the abundance, species diversity and community structure of two groups of mites (Oribatida and Gamasida). The effects of tillage, herbicide application, cover crop and mode of planting were evaluated in a 4 year-long replicated field experiment. Twenty-eight species of Oribatida and 35 species of Gamasida were represented in willow plantings. The predaceous Gamasida had more pronounced changes in abundance and diversity in response to the site preparation treatments than saprophagous and mycophagous Oribatida. Results indicated that (1) soil cultivation had negative effects on the abundance and diversity of soil mites during the first year of the experiment, later superceded by other factors; (2) the use or lack of tillage contributed to differences in mite community structure; and (3) following the initial disturbances, the abundance and diversity of soil mites increased in all treatments up to the end of the experiment. The success or failure of the willow crop and the changes in soil environments created by the different plant communities could explain the differences in soil mite populations among treatments best, especially 2 and 3 years after the beginning of the experiment. © 2003 Elsevier B.V. All rights reserved.

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Mirck, J., Volk, T.A. (2010). Response of three shrub willow varieties (Salix spp.) to storm water treatments with different concentrations of salts. Bioresource Technology,101(10), 3484-3492.  

Abstract
The effect of recycling storm water with high chloride concentrations on shrub willow growth was examined in a ten-week greenhouse study. Three willow varieties Salix miyabeana (SX64), Salix purpurea (9882-34), and Salix sachalinensis × Salix miyabeana (9870-40) were grown in organically-amended Solvay waste, and irrigated with five storm water concentrations containing 163, 325, 813, 1625, and 8125 mg Cl− L−1 and a tap water control. Stomatal conductance values responded most rapidly to stress (after 4.5 weeks), but height and leaf length measurements, which revealed signs of stress after 6 and 7 weeks, might be more practical stress indicators for large-scale plantations. Even though variety 9870-40 was most sensitive with increasing concentrations of Solvay storm water, this variety had the greatest ET values during the ten-week trial. Storm water with concentrations up to 1625 mg Cl− L−1 had no short-term effects on biomass accumulation and evapotranspiration.

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Mirck, J. and T.A. Volk, (2010). Seasonal Sap Flow of Four Salix Varieties Growing on the Solvay Wastebeds in Syracuse, NY, USA. International Journal of Phytoremediation.12(1), 1.

Abstract
Sap flow of four shrub willow varieties was measured to study their potential use as an evapotranspiration (ET) cover on the Solvay wastebeds to reduce deep percolation and leaching of chloride. Stem and stand-level sap flow and crop coefficients (K...) were different among four willow varieties measured between early June and mid November 2006. Diameter and cross sectional area had a significant impact on stand level sap flow. Peak stand-level sap flow of 7 mm d... occurred in June, due to coupling of the willow with the atmosphere, and not in July or August when peak LAI was measured. The coupling also resulted in high K... values of 3 in June and above 2 in October with an average of 1.1-1.3 for the entire season. Our measurements confirmed the potentials of shrub willow in ET cover applications in the northeastern USA. Total transpiration for the growing season ranged between 494 mm and 533 mm, which was about 45% of the precipitation in 2006. Our calculations showed a significant difference between peak season sap flow in June, July and August and sap flow over the course of the whole growing season, which showed the need for long-term measurements. (ProQuest: ... denotes formulae/symbols omitted.)

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Nordman, E.E., Robison, D.J., Abrahamson, L.P., Volk, T.A. (2005). Relative resistance of willow and poplar biomass production clones across a continuum of herbivorous insect specialization: Univariate and multivariate approaches. Forest Ecology and Management, 217(2-3), 307-318.

Abstract
Short-rotation woody crops (SRWC) are being developed as a sustainable system that simultaneously produces a renewable feedstock for bioenergy and bioproducts and a suite of environmental and rural development benefits. However, damage from defoliating insects can significantly reduce the yield of SRWC and negatively impact their sustainability. Information regarding the relative resistance to defoliation of different SRWC clones is not only useful for deployment and breeding choices, but can also help elucidate ecological patterns of herbivore specialization. Laboratory feeding bioassays tested the resistance of 19 willow (Salix spp.) and six poplar (Populus spp.) biomass production clones to feeding by seven common folivorous insects. Defoliation was measured using a leaf area meter and results were standardized according to leaf area consumed per insect per day. Significant differences in resistance were found among clones (p ≤ .05). The most folivore-resistant groups included the six poplar clones and willow clones SH3, SP3, S546 and S625. Willow clones with S. eriocephala or S. dasyclados parentage were generally less resistant to herbivory than those with other parentages. Comparisons of univariate and multivariate approaches found that the multivariate techniques are robust and conservative, and provide an efficient means of screening a large number of clones in a development program. The multivariate approach provided a clearer sorting of folivores along a continuum of insect specialization. Such sorting may be useful in selecting model folivores to use in tree genetic improvement screening systems to efficiently reveal which clones are more likely to be resistant to multiple insect pests. © 2005 Elsevier B.V. All rights reserved.

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Park, B.B., Yanai, R.D., Sahm, J.M., Lee, D.K., & Abrahamson, L.P. (2005). Wood ash effects on plant and soil in a willow bioenergy plantation. Biomass & Bioenergy, 28(4), 355-365.

Abstract
Intensive management for biomass production results in high rates of nutrient removal by harvesting. We tested whether wood ash generated when burning wood for energy could be used to ameliorate negative soil effects of short-rotation harvesting practices. We measured the temporal and spatial dynamics of soil nutrient properties after wood ash applications in a willow plantation in central New York State and determined the influence of wood ash application on willow growth. Wood ash was applied annually for 3 years at the rates of 10 and 20 Mg ha-1 to coppiced willow, Salix purpurea, clone SP3. Wood ash application significantly increased soil pH in the 0-10 cm soil layer from 6.1 in the control to 6.9 and 7.1 in the 10 and 20 Mg ha-1 treated plots. Wood ash application significantly increased soil extractable phosphorus, potassium, calcium, and magnesium concentrations. Potassium was the element most affected by wood ash treatment at all soil depths. Wood ash had no significant effect on nutrient concentrations of foliar, litter, and stem tissue. Wood ash did not affect either individual plant growth or plot biomass production, which declined over the course of the study; it did increase the size of stems, but this effect was balanced by a decrease in the number of stems. Applying nitrogen as well as wood ash might be required to maintain the productivity of this SRIC system. © 2004 Elsevier Ltd. All rights reserved.

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Park, B. B., Yanai, R. D., Sahm, J. M., Ballard, B. D., & Abrahamson, L. P. (2004). Wood ash effects on soil solution and nutrient budgets in a willow bioenergy plantation. Water, Air, and Soil Pollution, 159(1), 209-224. doi:10.1023/B:WATE.0000049177.60761.37

Abstract
The management of wood ash is an important factor in the environmental and economic analysis of wood burning. Wood ash can be applied to energy crops as a fertilizer, which can help replace nutrients removed during harvest. The objectives of this study were to examine the temporal and spatial dynamics of nutrient elements applied in wood ash to an intensively cultured, short-rotation willow bioenergy system. Wood ash was applied at the rates of 10 and 20 Mg ha-1 yr-1 to coppiced willow, Salix purpurea, clone SP3, from 1992 to 1994. The relative abundance of nutrients in applied wood ash was Ca > K > Mg > P > N. There was little effect of wood ash on N or P concentrations in soil solution measured at 20 and 40 cm depth. Soil solution concentrations of base cations were elevated in the last two years of the study by 30 to 90%, depending on the element and treatment, in plots receiving wood ash. Wood ash treatments had little influence on foliar leaching. Wood ash treatment also had few significant effects on willow growth or on the contents of N, P, K, Ca, and Mg in foliage and stems. The addition of P, K, Ca, and Mg in wood ash was more than enough to compensate for harvest removals and leaching losses. This study demonstrated that wood ash can supply most nutrients removed during harvest in willow plantations, with the exception of N, without adverse effects on groundwater or vegetation. © 2004 Kluwer Academic Publishers.

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Pian, C.C.P., Volk, T.A., Abrahamson, L.P., White, E.H., Jarnefeld, J. (2006). Biomass gasification for farm-based power generation applications. Waste Management and the Environment 3(1), 267-276.

Abstract
Willow biomass crops have been shown to be a good fuel for farm-based power production using advanced gasification technology. The fuel gas can be used for generating electricity, using microturbines modified to operate on low-BTU gas, or for other farm energy needs. Willow biomass was found to make an excellent fuel for ash-rejection gasifiers with a predicted net gasification efficiency of about 85 percent. The main drivers to the cost-of-electricity were found to be associated with the harvesting, handling, and transporting of the willow biomass, accounting for 40 to 50 percent of the annual operating cost. In the present study, analysis showed that developing a method to co-gasify willow with various amounts of low-cost wastes, such as dairy farm animal waste, can be an excellent way to reduce the fuel cost, to increase the overall fuel availability and help work around problems resulting from seasonal availability of bioenergy crops. Co-gasification of dairy farm wastes along with willow offers an economical way to dispose of the wastes and manage nutrient flows on a dairy farm. The power generated from the animal waste can be used on the farm or sold to offset the cost of waste treatment.

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Pian, C.C.P and T.A. Volk. 2009. Willow biomass gasification feasibility study. In: Badeau, J-P. and A. Levi. (eds). Biomass Gasification: Chemistry, Process and Applications. (pp. 71-86). Hauppage, NY: Nova Science Publishers.

Abstract
Willow biomass is found to be an excellent fuel for farm-based power generation by utilizing an advanced gasifier system that uses high-temperature preheated air as the gasification medium. The gasifier’s product fuel gas can be used in microturbines to generate electricity or used for other farm energy needs. The gasifier performance under various operating conditions is estimated using a previously developed gasifier model. The net gasification efficiency is about 85 percent under nominal operating conditions. The capital cost of a small, farm-based power system is estimated to be about $2,800/kW. Using the latest published information on willow biomass production cost, the cost of electricity is estimated to be 9 cents/kWh and is reduced to 7.2 cents/kWh when willow is grown on Conservation Reserve land. The costs associated with harvesting, handling, and transporting the willow biomass account for 40 to 50 percent of the annual operating cost. Results also show that co-gasification of willow with low-cost wastes, such as dairy farm animal wastes, can reduce fuel cost, increase the overall fuel availability and help work around problems resulting from seasonal availability of biomass crops. Co-gasification of willow biomass with manure waste also benefits the dairy industry by providing an economical way to dispose of farm wastes and manage nutrient flows.

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Smart, L.B., Volk, T.A., Lin, J., Kopp, R.F., Phillips, I.S., Cameron, K.D., White, E.H., Abrahamson, L.P. (2005). Genetic improvement of shrub willow (Salix spp.) crops for bioenergy and environmental applications in the United States. Unasylva, 56(221), 51-55.

Abstract
The willow breeding programme at the College of Environmental Science and Forestry of the State University of New York (SUNY-ESF) is the largest in North America, with over 730 accessions collected from natural sites across the United States and provided by international collaborators. This article describes controlled breeding work carried out at SUNY-ESF which has produced some crosses with growth improved 20 to 40 percent over that of a standard cultivar. The authors believe that such results, if confirmed in regional trials over the long term, could help encourage widespread adoption of willow crops in the United States.

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Teece, M.A., Zengeya, T., Volk, T.A., Smart, L.B. (2008). Cuticular wax composition of Salix varieties in relation to biomass productivity. Phytochemistry, 69(2), 396-402.

Abstract
The leaf cuticular waxes of six Salix clones (one Salix miyabeana, one Salix dasyclados, one Salix eriocephala, two Salix purpurea, and one interspecific hybrid of Salix eriocephala × interior) with different biomass productivities were characterized by gas chromatography-mass spectrometry. Total wax content ranged from 6.3 to 16.8 μg cm-2, and two distinct patterns of wax were measured. The wax from leaves of S. dasyclados 'SV1' differed from all other clones and was dominated by fatty acids (42%), high concentrations of n-alkanes (25%) and n-alcohols (28%), with low n-aldehyde content (4%). All other clones produced cuticular wax dominated by n-alcohols (32-51%), particularly 1-hexacosanol, with fatty acids (14-37%) and n-aldehydes (19-26%) present in lower abundances. Clones of Salix grown under identical environmental conditions produce noticeably different amounts of cuticular wax. In contrast to previous studies of Salix, total wax content was independent of biomass productivity, measured as basal area, suggesting that wax production is not directly linked with woody biomass production by shrub willows under these site conditions. © 2007 Elsevier Ltd. All rights reserved.

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Tharakan, P. J., Robison, D. J., Abrahamson, L. P., & Nowak, C. A. (2001). Multivariate approach for integrated evaluation of clonal biomass production potential. Biomass and Bioenergy, 21(4), 237-247. doi:10.1016/S0961-9534(01)00038-1

Abstract
Evaluating the performance of clones to be used in short rotation intensive culture (SRIC) plantations for biomass production is critical for identifying superior clones and matching them with sites on which they will perform best. This will lead to increased production and a strengthening of the commercial prospects of these plantations. The primary objective of this study was to use a multivariate approach to evaluate the relative clonal performance of 38 willow and hybrid poplar clones, deployed in a genetic selection trial based on a coppice rotation system established in central New York State (NY) in 1997. Cluster analysis was conducted using survival, several individual plant growth attributes, and insect defoliation, all measured during or at the end of 1998. Two linear functions developed using discriminant analysis, comprising primarily of attributes related to tree vigor and site adaptability; tree volume index and length of growing period, explained most of the variation (98.5%) among the clusters. Eight of the 38 clones evaluated are expected to be high biomass producers, and are recommended for more extensive clone-site trials and commercial scale plantations across central NY and the northeastern United States (US). The results of this study indicate a possible approach to more effective juvenile selection in tree improvement programs, and insights for a refinement of the current SRIC tree ideotype. © 2001 Elsevier Science Ltd. All rights reserved.

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Tharakan, P.J., Volk, T.A., Abrahamson, L.P., White, E.H. (2003). Energy feedstock characteristics of willow and hybrid poplar clones at harvest age. Biomass and Bioenergy, 25(6), 571-580.

Abstract
Woody biomass feedstock produced from willow and hybrid poplar can be converted into bioenergy via thermochemical and biochemical processes. Variation in key properties that relate to the quality of biomass feedstock and determine its value for energy conversion were determined at rotation age (3 years), in 30 willow and seven hybrid poplar clones, grown in a short-rotation intensive culture (SRIC) system in central NY. Substantial clonal variation in the concentrations of nitrogen (2.9-5.0 g kg-1), phosphorus (0.4-0.8 g kg-1) potassium (1.2-2.4 g kg-1), sodium (0.09-0.20 g kg-1), calcium (3.9-8.9 g kg-1), magnesium (0.2-0.6 g kg-1), ash (13.2-27.2 g kg-1) and bark percentage (3.6-8.1%) was found in stem (bark + wood) samples. A lower amount of variation was documented for specific gravity (0.33-0.48 g cm-3) and percent moisture (49-56%). Bark had a higher concentration of inorganic elements and ash, relative to wood. Willow clones as a group had a higher specific gravity, bark percentage and calcium concentration relative to hybrid poplar clones, which had a higher potassium concentration. The two groups were similar in terms of the concentrations of other elements and ash. Clonal variation in these characteristics present opportunities for manipulating feedstock quality through selection, breeding and plantation management. © 2003 Elsevier Ltd. All rights reserved.

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Tharakan, P.J., Volk, T.A., Lindsey, C.A., Abrahamson, L.P., White, E.H. (2005). Evaluating the impact of three incentive programs on the economics of co-firing willow biomass with coal in New York State. Energy Policy, 33(3), 337-347.

Abstract
Plantations of fast-growing willow shrubs are being promoted as a source quality biomass feedstock for bioenergy and bioproducts in New York State (NY). In the near-term, co-firing of the feedstock-in combination with other woody biomass-with coal in existing utility power boilers is considered to be the most promising conversion method for energy generation. Despite the clear technological viability and associated environmental benefits, co-firing of willow has not been widely adopted. The relatively high production cost of the willow feedstock, which is over twice that of coal, is the primary reason for this lack of interest. Taxes that account for some of the social costs of using coal and/or incentives that appropriate value for some of the social benefits of using willow are essential for eliminating most or the entire current price differential. This paper presents an integrated analysis of the economics of power generation from co-firing willow biomass feedstock with coal, from the perspective of the grower, aggregator and the power plant. Emphasis is placed on analyzing the relative impact of a green premium price, a closed-loop biomass tax credit, and payments to growers under the proposed Conservation Reserve Program (CRP) harvesting exemption policy. The CRP payments reduced the delivered cost of willow by 36-35%, to $ 1.90 GJ-1 and $ 1.70 GJ-1, under current and increased yield conditions, respectively. These prices are still high, relative to coal. Other incentives are required to ensure commercial viability. The required levels of green premium price (0.4-1.0 cents kWh-1) and biomass tax credit (0.75-2.4 cents kWh-1) vary depending on whether the incentives were being applied by themselves or in combination, and whether current yield or potential increased yields were being considered. In the near term, co-firing willow biomass and coal can be an economically viable option for power generation in NY if the expected overall beneficial effects associated with the production and use of the biomass is accounted for. © 2003 Elsevier Ltd. All rights reserved.

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Tharakan, P.J., Volk, T.A., Nowak, C.A., Abrahamson, L.P. (2005). Morphological traits of 30 willow clones and their relationship to biomass production. Canadian Journal of Forest Research, 35(2), 421-431.

Abstract
The relatively high cost of willow (Salix spp.) biomass feedstock compared with fossil fuels makes it imperative to reduce production costs by increasing yields and reducing input costs. This can be addressed by harnessing the genetic potential of willow based on an understanding of the variation in key traits and how they interact to influence biomass production. Variation in 11 morphological traits among 30 willow clones at the end of a 3-year rotation was analyzed to determine its relationship to biomass production. We found significant differences (p ≤ 0.001) among the 30 clones in all traits. Across all clones, several significant trait correlations were detected. Cluster analysis revealed that high-yielding clones could be separated into two distinct "functional types" characterized by alternate growth strategies. One set of clones was characterized by a large number of small diameter stems, relatively low leaf area index and specific leaf area, but high foliar nitrogen and wood specific gravity. The other was characterized by a small number of large diameter stems, high leaf area index and specific leaf area, but low foliar nitrogen and wood specific gravity. The differences in strategies were apparent at the species level as well. These results suggest that multiple ideotypes need to be incorporated into willow breeding and selection efforts and in the management of willow biomass crops. © 2005 NRC Canada.

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Tharakan, P.J., Volk, T.A., Nowak, C.A. and G. Ofezu. (2008). Canopy Structure, Light Interception, and Light-Use Efficiency in Willow. BioEnergy Research. 1(3-4), 229 – 238.

Abstract

According to the light-use efficiency model, differential biomass production among willow varieties may be attributed either to differences in the amount of light intercepted, the efficiency with which the intercepted light is converted to aboveground biomass, or both. In this study, variation in aboveground biomass production (AGBP) was analyzed in relation to fraction of incoming radiation intercepted (IPARF) and light-use efficiency (LUE) for five willow varieties. The plants were grown in a short-rotation woody crop (SRWC) system and were in their first year of regrowth on a 5 year old root system. The study was conducted during a two-month period (June 15th–August 15th, 2001) when growing conditions were deemed most favorable. The objectives were: (1) to assess the relative importance of IPARF in explaining variation in AGBP, and (2) to identify the key drivers of variation in LUE from a suite of measured leaf and canopy-level traits. Aboveground biomass production varied nearly three-fold among genotypes (3.55–10.02 Mg ha−1), while LUE spanned a two-fold range (1.21–2.52 g MJ−1). At peak leaf area index (LAI), IPARF ranged from 66%–92%. Nonetheless, both IPARF and LUE contributed to AGBP. An additive model combining photosynthesis on leaf area basis (Aarea), leaf mass per unit area (LMA), and light extinction coefficient (k) produced the most compelling predictors of LUE. In a post-coppice willow crop, the ability to maximize IPARF and LUE early in the growing season is advantageous for maximizing biomass production.

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Volk, T.A., Abrahamson, L.P., Nowak, C.A., Smart, L.B., Tharakan, P.J., White, E.H. (2006). The development of short-rotation willow in the northeastern United States for bioenergy and bioproducts, agroforestry and phytoremediation. Biomass and Bioenergy, 30(8-9), 715-727.

Abstract
Research on willow (Salix spp.) as a locally produced, renewable feedstock for bioenergy and bioproducts began in New York in the mid-1980s in response to growing concerns about environmental impacts associated with fossil fuels and declining rural economies. Simultaneous and integrated activities-including research, large-scale demonstrations, outreach and education, and market development-were initiated in the mid-1990s to facilitate the commercialization of willow biomass crops. Despite technological viability and associated environmental and local economic benefits, the high price of willow biomass relative to coal has been a barrier to wide-scale deployment of this system. The cost of willow biomass is currently $ 3.00 GJ- 1 ($ 57.30 odt- 1) compared to $ 1.40 - 1.90 GJ- 1 for coal. Yield improvements from traditional breeding efforts and increases in harvesting efficiency that are currently being realized promise to reduce the price differential. Recent policy changes at the federal level, including the provision to harvest bioenergy crops from Conservation Reserve Program (CRP) land and a closed-loop biomass tax credit, and state-level initiatives such as Renewable Portfolio Standards (RPS) will help to further reduce the difference and foster markets for willow biomass. Years of work on willow biomass crop research and demonstration projects have increased our understanding of the biology, ecophysiology and management of willow biomass crops. Using an adaptive management model, this information has led to the deployment of willow for other applications such as phytoremediation, living snowfences, and riparian buffers across the northeastern US. © 2006.

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Volk, T.A., Ballard, B., Robison, D.J., Abrahamson, L.P. (2004). Effect of cutting storage conditions during planting operations on the survival and biomass production of four willow (Salix L.) clones. New Forests, 28(1), 63-78.

Abstract
Planting vigorous cuttings that quickly develop shoots and roots is essential to the biological and economic success of willow biomass crops. Current recommendations are that cuttings should be planted within 24 days of being removed from long-term cold storage at -4°C. However, maintaining this short time period is not always feasible. Results from greenhouse and field experiments indicated that leaving cuttings out of -4°C long-term cold storage for up to 12 days before planting did not have a significant impact on survival or biomass production. For cuttings removed from long-term cold storage 23 days before planting, survival and per tree biomass production were lower for three of the four clones tested in a field trial. Returning cuttings to a -20°C freezer 59 days after removal from -4°C long-term cold storage, reduced the proportion of cuttings that developed roots or shoots, and shoot biomass of all clones. However, returning cuttings to either a +2°C cooler or a -4°C freezer had no effect on shoot biomass after 3 weeks of growth. Returning cuttings to supplemental cold storage at +2 to -4°C may extend the time that cutting viability can be maintained after being removed from long-term cold storage and thawed. Returning cuttings to a -20°C freezer for supplemental storage is not recommended.

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Volk, T.A., Fahey, T.J. (1994). Fifty-three years of change in an upland forest in south-central New York: Growth, mortality and recruitment. Bulletin of the Torrey Botanical Club, 121(2), 140-147.

Abstract
The contributions of growth, mortality and recruitment to long-term changes in the composition and structure of an Allegheny northern hardwood forest were quantified for a set of four permanent plots in south-central New York. Increment cores, taken from all trees ≥ 10 cm dbh, indicated that more than half (53.3%) of the stems inventoried in 1935 died before 1988. Mortality was highest on an unthinned plot (62.8%) and least (37.5%) on the plot with the lowest initial basal area. Mortality was highest for the short lived, shade intolerant species (e.g., black cherry [100%] and black birch [83%]) and lowest for longer lived, more shade tolerant species (e.g., sugar maple [34%] and beech [51%]). Relative growth rates of overstory trees were significantly lower on an unthinned plot than on three thinned plots for two decades after thinning. Sugar maple appeared to be the most responsive species to thinning. Growth rates of basswood declined markedly from 1930-1987. These results suggested that sugar maple would continue to dominate these plots while basswood and beech would become less important in the future forest.

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Volk, T.A., Verwijst, T., Tharakan, P.J., and Abrahamson, L.P. (2004). Growing energy: Assessing the sustainability of willow short-rotation woody crops. Frontiers in Ecology and the Environment. 2(8), 411-418.

Abstract

Global energy use projections predict that biomass will be an important source of renewable energy in the coming decades. Short-rotation woody crops will be the prime source of this biomass. However, the sustainability of woody crops has been questioned. Using internationally accepted forest sustainability criteria, an assessment of willow biomass crops indicates that they are sustainable compared to agricultural land and the fossil fuel-based energy systems they will replace. Assessing each criterion also reveals aspects of willow crop systems that should be addressed to further improve sustainability. Biological characteristics and management of willow create a structurally diverse habitat for an array of species and protect soil and water resources. Biomass from willow crops can be used to produce energy with no net addition of CO2 to the atmosphere. The implementation of good management practices will maintain productivity over multiple rotations. Rural development and environmental benefits associated with deployment and use will accrue to the local community because of the willow system's short supply chain. The economic valuation of these benefits are necessary for the deployment of woody crops, which in turn can help society become more sustainable.


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