University of Hawai‘i at Manoa
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Travis  Idol

Name :

Travis Idol

Title :

Associate Professor & Department Undergraduate Advisor

Unit :

Department of Natural Resources and Environmental Management

Address :

1910 East-West Road
                    Honolulu, HI 96822

Room :

Sherman Lab 125

Phone :


Fax :


E-mail :

Website :

Specialties :

Forestry, agroforestry

Professional Prep/Appointments :

B.S. Wake Forest University M.S. Purdue University P.h.D. Purdue University

Projects :

Shade Coffee Agroecosystems in Hawaii
Prodcutivity, Silviculture, and Regeneration of Acacia koa
Restoration Agroforestry
Silvopasture with Leucaena

Courses Taught:

NREM 292/492: NREM Internship
NREM 306: Environmental Ethics
NREM 380: Tropical Forestry and Agroforestry
NREM 480: Applied Forest Ecology
NREM 691: Forest Nutrition and Biogeochemistry
NREM 695/696: MEM Capstone

Research Interests :

Forest nutrition
Ecosystem nutrient cycling
Fine root dynamics
Silviculture & reforestation
Agroforestry design & analysis
Conservation agriculture

Selected Publications :

Peer-Reviewed Journal Articles

Idol TW, RM Morales, JB Friday, and PG Scowcroft. 2017. Precommercial release thinning of potential Acacia koa crop trees increases stem and crown growth in dense, 8-year-old stands in Hawaii. Forest Ecology and Management 392:105-114. doi: 10.1016/j.foreco.2017.02.029

Idol TW and G. Diarra. 2017. Mycorrhizal colonization is compatible with exponential fertilization to improve tree seedling quality. Journal of Plant Nutrition 40: 283-297. doi: 10.1080/01904167.2016.1240188

Pradhan A, Idol T and Roul PV. 2016. Conservation agriculture practices in rainfed uplands of India improve maize-based system productivity and profitability. Frontiers in Plant Science 7 (1008). doi: 10.3389/fpls.2016.01008.

Youkhana A and TW Idol. 2016. Leucaena-KX2 mulch additions incerase growth, yield and soil C and N in a managed full-sun coffee system in Hawaii. Agroforestry Systems 90:325-337. doi: 10.1007/s10457-015-9857-z.

Lai C, C Chan, J Halbrendt, L Shariq, P Roul, T Idol, C Ray, and C Evensen. 2012. Comparative economic and gender, labor analysis of conservation agriculture practices in tribal villages in India. International Food and Agribusiness Management Review 15:73-86.

Martinez Morales R, Idol TW, Friday JB, and Chen Q. 2012. Differentiation of koa forest stands across an elevation gradient in Hawaii using fine resolution remotely sensed imagery. International Journal of Remote Sensing 33:3492-3511. doi:10.1080/01431161.2011.629234

Brandeis T, Kuegler O, Pattison R, …Idol T, et al. 2011. Pacific rim forestry. Journal of Forestry 109:485-490.

Coufal J, Wiedemann C, Gorman J,…Idol T, et al. 2011. Consulting forestry/certification and ecosystem services. Journal of Forestry 109:530-537.

Martinez Morales R, Idol T, and Friday JB. 2011. Assessment of Acacia koa forest health across environmental gradients using fine resolution remote sensing and GIS. Sensors 11:5677-5694. doi:10.3390/s110605677

Moore S, Sills E, Allen L, ...Idol T, et al. 2011. Global competency and issues in contemporary education/agroforestry. Journal of Forestry 109:545-552.

Steiman S, Idol TW, and Bittenbender HC. 2011. Shade coffee in Hawaii-exploring some aspects of quality, growth, yield, and nutrition. Scientiae Horticulturae 158:152-158. doi:10.1016/j.scienta.2011.01.011.

Youkhana A and Idol T. 2011. Addition of Leucaena-KX2 mulch in a shaded coffee agroforestry system increases both stable and labile soil C fractions. Soil Biology and Biochemistry 43:961-966. doi:10.1016/j.soilbio.2011.01.011

Youkhana A and Idol T. 2011. Allometric models for predicting above- and belowground biomass of Leucaena-KX2 in a shaded coffee agroecosystem in Hawaii. Agroforestry Systems. 83:331-345 doi: 10.1007/s10457-011-9403-6.

Youkhana A and Idol T. 2011. Growth, yield and value of managed coffee agroecosystem in Hawaii. Pacific Agriculture and Natural Resources. 2:12-19.

Scowcroft PG, Friday JB, Haraguchi J, Idol TW, and Dudley N. 2010. Poor stem form as a potential obstacle to private investment in koa plantation forestry in Hawaii. Small-Scale Forestry 9:243-262. doi: 10.1007/s11842-009-9107-1

Youkhana A and Idol TW. 2009. Tree pruning mulch increases soil carbon and nitrogen in shade and full sun coffee agroecosystems in Hawaii. Soil Biology and Biochemistry. 41:2527-2534.

Meason DF, Idol TW, Friday JB, and Scowcroft PG. 2009. Persistence of elevated phosphorus availability after fertilisation in the volcanic soil of a managed tropical forest. Forest Ecology and Management 258:2199-2206.

Meason D and Idol TW. 2008. Comparison of ion exchange resin membranes (PRS-probes) with resin bags in the field: effects of incubation time, soil depth, and P fertilization. Soil Science Society of America Journal 72:1806-1814.

Youkhana A and Idol T. 2008. First-year biomass production and soil improvement in young Leucaena and Robinia stands under different pollarding systems. Journal of Tropical Forest Science 20:181-187.

Martinez Morales R, Miura T, and Idol T. 2008. An assessment of Hawaiian dry forest condition and restoration potential with fine resolution remote sensing. Forest Ecology and Management 255:2524-2532.

Steiman SR, Idol TW, and Bittenbender HC. 2007. Analysis of kaolin particle film usage and its application on coffee. HortScience 42:1605-1608.

Idol TW, Baker PJ, and Meason D. 2007. Indicators of forest ecosystem productivity and nutrient status across precipitation and temperature gradients in Hawaii. Journal of Tropical Ecology 23:693-704.

Scowcroft PG, Friday JB, Idol TW, Dudley N, Haraguchi J, and Meason D. 2007. Growth response of Acacia koa trees to thinning, grass control, and phosphorus fertilization in a secondary stand in Hawaii. For. Ecol. Manage. 239:69-80.

Idol TW, Pope PE, and Ponder Jr F. 2003. N mineralization, nitrification, and N uptake across a 100-year chronosequence of upland hardwood forests. For. Ecol. Manage. 176:509-518.

Idol TW, Pope PE, and Ponder Jr F. 2002. Changes in microbial nitrogen across a 100-year chronosequence of upland hardwood forests. Soil Sci. Soc. Am. J. 66:1662-1668.

Idol TW, Holzbaur KA, Pope PE, and Ponder Jr F. 2002. Control-bag correction for forest floor litterbag contamination. Soil Sci. Soc. Am. J. 66:620-623.

Idol TW, Figler RA, Pope PE, and Ponder Jr F. 2001. Characterization of coarse woody debris across a 100 year chronosequence of upland oak-hickory forests. For. Ecol. Manage. 149:153-161.

Idol TW, Pope PE, and Ponder Jr. F. 2000. Fine root dynamics across a chronosequence of upland temperate deciduous forests. Forest Ecology and Management

Book Chapters

Idol T. 2015. A brief history of conservation agriculture. In C. Chan-Halbrendt and J. Fantle-Lepczyk (eds.) Conservation Agriculture in Susbsistence Farming: Case Studies from South Asia and Beyond. CABI, Oxford. pp. 1-21.

Pradhan A, T. Idol, P.K. Roul, K.N. Mishra, C. Chan-Halbrendt, J. Halbrendt, and C. Ray. 2015. Effect of tillage, intercropping and residue cover on crop productivity, profitability and soil fertility under tribal farming situations of India. In C. Chan-Halbrendt and J. Fantle-Lepczyk (eds.) Conservation Agriculture in Susbsistence Farming: Case Studies from South Asia and Beyond. CABI, Oxford. pp. 77-94.

Roul P.K., A Pradhan, P. Ray, K.N. Mishra, S.N. Dash, C. Chan-Halbrendt, T. Idol and C. Ray. 2015. Influence of maize-based conservation agricultural production systems (CAPS) on crop yield, profitability and soil fertility in rainfed uplands of Odisha, India. In C. Chan-Halbrendt and J. Fantle-Lepczyk (eds.) Conservation Agriculture in Susbsistence Farming: Case Studies from South Asia and Beyond. CABI, Oxford. pp. 95-108.

Idol T, Haggar J, and Cox L. 2011. Ecosystem services from smallholder forestry and agroforestry in the tropics. p. 209-270 In WB Campbell and SL Lopez (eds.) Integrating agriculture, conservation, and ecotourism: examples from the field. Springer, New York.

Conference Proceedings Papers

Idol T. 2017. Stand management of koa: thinning and fertilization. Acacia koa in Hawaii: facing the future. 2016 Conference Proceedings. Hilo, HI.

Lai, C., C. Chan-Halbrendt, J. Halbrendt, P. Roul, T. Idol, C. Ray and C. Evensen. 2011. Comparative economic analysis of conservation agricultural practices in tribal villages in India. Proceedings of the 21st Annual IFAMA World Forum and Symposium in Frankfurt, Germany (June 2011).

Idol TW, Steiman S, Bittenbender HC, Gautz L, and Jackson, M. 2007. Not all shade is created equal: reflections on shade management based on preliminary studies from Hawaii. Second International Symposium on Multi-Strata Agroforestry Systems with Perennial Crops. Sept. 17-22, 2007. CATIE, Turrialba, Costa Rica.

Steiman S, Bittenbender HC, Idol TW, Gautz LD, Jackson MC. 2007. Shade coffee in Hawaii --the impact of light on coffee quality. 21st International Conference on Coffee Science, Montpellier, France, 11-15 September, 2006. Paris: Association Scientifique Internationale du Cafe (ASIC), p.1214-1216.

Steiman S, Idol TW, Bittenbender HC, Gautz LD, Jackson MC. 2007. Physiological response of coffee to different shading regimes. 21st International Conference on Coffee Science, Montpellier, France, 11-15 September, 2006. Paris: Association Scientifique Internationale du Cafe (ASIC), p.1212-1213.

Jackson MC, Steiman SR, Gautz LD, Bittenbender HC, Idol TW. 2007. Quality determination and group discrimination of shade grown coffee using solid phase microextraction as a means of coffee discrimination. 21st International Conference on Coffee Science, Montpellier, France, 11-15 September, 2006. Paris: Association Scientifique Internationale du Cafe (ASIC), p. 306-309.

Idol TW, Pope PE, and Ponder Jr F. 2002. The effects of harvesting on long-term soil productivity in southern Indiana oak-hickory forests. pp. 233-238 In Outcalt, K.W. (Ed.) Proc. 11th Bienn. South. Silvic. Res. Conf., Mar. 20-22, 2001, Knoxville, TN. Gen. Tech. Rep. SRS-48. U.S. Dept. Agric., For. Serv., South. Res. Stn, Asheville, N.C.

Idol TW, Pope PE, Tucker J, and Ponder Jr F. 1998. The role of fine root dynamics in the N and P cycles of regenerating upland oak-hickory forests. pp. 136-140 In Waldrop, T.A. (Ed.) Proc. 9th Bienn. South. Silv. Res. Conf., Feb. 25-27, 1997, Clemson, SC. Gen. Tech. Rep. SRS-20, US Dept. Agric., Forest Service, Southern Research Station, Asheville, NC.

Technical Papers, Trade Journals, and Other Reports

Idol TW and G. Diarra. 2013. Sustainable practices to boost tree seedling performance. Hanai Ai Spring 2013. 7 pp.

Idol TW. 2012. History of forestry in Hawaii: an overview. Hawaii Forest Journal 6:1-2.

Idol TW. 2012. Ecosystem services from trees in coffee agroecosystems. Hanai Ai, Spring 2012. 4 pp.

Idol TW and Youkhana A. 2010. Managing shade trees for coffee can benefit the soil. Hanai Ai, Winter 2010. 2 pp.

Elevitch C., Idol T, Friday J. B., Lepczyk C., Easton Smith V., and Nelson S. C. 2009. Shade-grown coffee for Hawaii: results of a twelve farm study in Kona. Permanent Agriculture Resources, Holualua, HI. 22 pp.

Idol TW, Scowcroft PG, Dudley N, Dancil K, and Simmons P. 2007. The value of managing Acacia koa forests. Hawaii Forest Journal 2:8-11.

Radovich T, LJ Cox, J Sugano, and T Idol. 2009. Benefits and costs of using perennial peanut as living mulch for fruit trees in Hawaii. SCM-27. University of Hawaii, College of Tropical Agriculture and Human Resources, Soil and Crop Management report.

Book Reviews

Idol TW. 2007. Rev. of Tropical homegardens: a time-tested example of sustainable agroforestry. Edited by B.M. Kumar and P.K.R. Nair. Forest Science. 53:710.

Idol TW. 2005. Rev. of Profiles in the history of the U.S. soil survey. Edited by D. Helms, A.B.W. Effland, and P.J. Durana. Journal of Southern History 71:971-972.