Prospects for commercial tree farming in Colombia

Main Article Content

Robert R. Davis https://orcid.org/0009-0005-2493-4400
Rafael De la Torre https://orcid.org/0000-0002-9761-8442
Frederick Cubbage https://orcid.org/0000-0001-8375-3945
Bruno Kanieski da Silva https://orcid.org/0000-0002-4007-2717

Keywords

acacia, carbon sequestration, Colombia, eucalyptus, forestry, growth rates, investment returns, pine, risks, tree planting

Abstract

Over the next few decades, the area of planted forests required to satisfy worldwide demand for fiber, timber, and environmental services will need to increase by tens of millions of hectares (Mha). As no single nation can accommodate this expansion, planting sites in multiple countries must be identified. One prospective location is Colombia, which boasts nearly 26 Mha of land suitable for commercial tree planting, fair-to-excellent growth rates for major industrial species, good professional expertise, seaports on the Pacific and Caribbean coasts, and low-to-moderate land prices. Yet, despite these outstanding assets, tree plantations in Colombia cover only 542 thousand hectares (ha), with almost 90 percent located in three distinct regions: the Andean, Orinoco, and Caribbean. Constraints to commercial tree farming in Colombia include cultural preferences for non-wood products in construction and domestic applications, low capacity for processing industrial roundwood, and lack of reliable wood supplies needed for firms to scale up operations. While land prices are attractive in the remote Orinoco Region, they are considerably higher in more accessible regions, such as the Andean and Caribbean, which are closer to markets, mills, and ports. These factors along with security problems, low levels of formal land titling, and property rights issues in rural areas can complicate operations and add risk to investments in plantation forestry. With land for tree planting at a premium and increasing global demand for wood, fiber, and carbon sequestration, Colombia’s plantation sector stands to profit, provided it can successfully address the barriers to its growth.

Abstract 320 | View Full Text Downloads 0 Download PDF Downloads 67

References

Aldana-Domínguez J, Montes C, Martínez M, Medina N, Hahn J, Duque M. Biodiversity and ecosystem services knowledge in the Colombian Caribbean: progress and challenges. Tropical Conservation Science. 2017;10. https://doi.org/10.1177/1940082917714229

Arango J. 2018. Collective land tenure in Colombia data and trends. Info brief. CIFOR. Bogor, Indonesia: https://www.cifor.org/knowledge/publication/6877/. Accessed March 16, 2023.

Ariza A, Gutiérrez E, Calvo L. 2022. Consecuencias del conflicto armado en la producción del sector agrícola de Colombia. Artículo de revisión bibliográfica para optar por el título de especialista en gerencia financiera. Fundación Universitaria Del Área Andina. Facultad de Ciencias Administrativas Económicas y Financieras. Bogotá D.C. Available from: https://digitk.areandina.edu.co/bitstream/handle/areandina/5076/Trabajo%20de%20grado.pdf?sequence=1&isAllowed=y#:~:text=En%20Colombia%20la%20violencia%20del,población%20rural%2C%20desempleo%20y%20pobreza. Accessed February 9, 2024.

Bartholomäus A, Cortés A, Gutiérrez, J, Duarte LE, Moosbrugger, W. 1998. El manto de la tierra: flora de los Andes. Corpinus Autónoma Regional de las Cuencas de los Rios Bogotá, Ubaté y Suárez (CAR). Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ). Kreditanstaff für Wiederaufbau (KFW). Bogotá, Colombia.

Bloomberg. 2022. Carbon offset price may rise 3,000% by 2029 under tighter rules. Functions for the Market March 02, 2022. Available from: https://www.bloomberg.com/professional/blog/carbon-offsets-price-may-rise-3000-by-2029-under-tighter-rules/. Accessed November 12, 2023.

Braun F, Held C (eds.). 2017. Análisis de las cadenas de valor y de la logística de plantaciones forestales con fines comerciales en Colombia. PROFOR. The World Bank. Washington, DC: https://www.profor.info/sites/profor.info/files/Análisis%20de%20las%20cadenas%20de%20valor%20y%20de%20la%20log%C3%ADstica%20de%20plantaciones%20forestales%20con%20fines%20comerciales%20en%20Colombia.pdf. Accessed March 16, 2023.

Brazilian Tree Industry (IBÁ). 2022. Annual Report 2022. Available from:
https://iba.org/eng/datafiles/publicacoes/relatorios/relatorio-iba2022-en-2022-12-06-compressed.pdf. Accessed November 1, 2023.

Britannica, The Editors of Encyclopaedia. “Llanos”. Encyclopedia Britannica, 23 Aug. 2023, https://www.britannica.com/place/Llanos. Accessed November 1, 2023.

Calderón M. 2021. Resumen Público, Plan de Manejo Forestal Aldea Forestal S.A. Bogotá, Colombia: https://forliance.com/wp-content/uploads/2021/10/SIG-PN-Resumen-Publico-V3-OCT-2021.pdf. Accessed March 16, 2023.

CarbonCredits.com. 2023. Latest Carbon Prices. https://carboncredits.com. Accessed October 9, 2023.

Castaño CJ. 2023. (Manager of Silvotecnia). Personal communication to Rafael de la Torre, co-author, on October 25, 2023. Bogotá, Colombia.

Cbonds. 2023. S&P Global Ratings affirms Colombia at BBB-. January 23, 2023: https://cbonds.com/news/2134366/. Accessed March 16, 2023.

Cipreses de Colombia S.A. 2017. Plan de manejo forestal de la empresa Cipreses de Colombia S.A. Cipreses de Colombia S.A.: https://nucleosdemadera.com/wp-content/uploads/2017/10/RESUMEN-PÚBLICO-PLAN-DE-MANEJO-2017.pdf. Accessed March 16, 2023.

Convention on Biodiversity (CBD). n.d. Colombia – main details, biodiversity facts, status and trends of biodiversity, including benefits from biodiversity and ecosystem services: https://www.cbd.int/countries/profile/?country=co. Accessed March 9, 2023.

Cubbage F, Rubilar R, Mac Donagh, P, Kanieski Da Silva, B, Bussoni A, Morales V, Balmelli G, Afonso Hoeflich V, Lord R, Hernández C, Zhang P, Tran Thi Thu h, Yao R, Hall P, Korhonen J, Díaz-Balteiro L, Rodríguez-Soalleiro R, Davis R, Chudy R, De La Torre R, Jaime Lopera G, Phimmavong S, Garzón S, Cubas-Baez A. 2022. Comparative global timber investment costs, returns, and applications, 2020. Journal of Forest Business Research 1(1):90-121. https://doi.org/10.62320/jfbr.v1i1.16

Departamento Administrativo Nacional de Estadística. 2014. Censo Nacional Agropecuario. Bogotá D.C., Colombia, Departamento Nacional de Estadística: https://www.dane.gov.co/index.php/estadisticas-por-tema/agropecuario/censo-nacional-agropecuario-2014. Accessed March 16, 2023.

Departamento Administrativo Nacional de Estadística. 2022. Nota Estadistica. Propiedad rural en Colombia. Bogotá D.C., Colombia, Departamento Nacional de Estadística: https://www.dane.gov.co/files/investigaciones/notas-estadisticas/jul_2022_nota_estadistica_propiedad_rural.pdf. Accessed March 16, 2023.

De La Torre, R. 2023. (Manager of Forest Planning and Analysis, ArborGen Inc.) Personal communication to Robert Davis, lead author on October 25, 2023. South Carolina, USA.

FAO. 2007. Overview of forest pests, Colombia. Forest Health and Biosecurity Working Papers. FAO. Rome, Italy: https://www.fao.org/3/ak986e/ak986e00.pdf. Accessed March 16, 2023.

FAO. 2020. Global Forest Resources Assessment 2020, Main Report. Food and Agriculture Organization of the United Nations. Rome, Italy. Available from: https://www.fao.org/documents/card/en?details=ca9825en. Accessed January 18, 2024.

Financiamiento del Sector Agropecuario (FinAgro). 2016. Base de datos obtenido bajo el acuerdo entre el fondo para el financiamiento del sector agropecuario – FinAgro y Rafael Eduardo de la Torre Sosa, firmado 12 de Agosto de 2016. Bogotá, Colombia.

FinAgro. 2018. Ficha de inteligencia, reforestación comercial. Bogotá, Colombia: https://www.finagro.com.co/sites/default/files/node/basic-page/files/ficha_reforestacion_version_ii.pdf. Accessed November 1, 2023.

FinAgro. 2020a. AgroGuía. Pinus patula. MADR. Available from: https://www.finagro.com.co/sites/default/files/2022-05/pinus_patula_mra.pdf. Accessed November 1, 2023.

FinAgro. 2020b. AgroGuía. Eucalyptus pellita. MADR. Available from: https://www.finagro.com.co/sites/default/files/2022-05/eucaliptus_pellita_mra_13092021.pdf. Accessed November 1, 2023.

Federación Nacional de Industriales de la Madera (FEDEMADERAS). 2023a. ¿Cómo se monitorea la venta de madera legal en Colombia? Febrero 2, 2023. https://fedemaderas.org.co/como-se-monitorea-la-venta-de-madera-legal-en-colombia/. Accessed February 14, 2024.

FEDEMADERAS. 2023b. About Us.https://fedemaderas.org.co/quienes-somos/nosotros/fedemaderas-en/. Accessed October 5, 2023.

Florida Institute of Human and Machine Cognition (IHMC). n.d. Florida University System. USA. Available from: https://cmapspublic2.ihmc.us/rid=1JT1B9QVK-1RW6N49-DR/regionesnaturales.gif Accessed October 5, 2023.

Forest First S.A.S. 2020. Project description. Forest First S.A.S. Colombia: https://www3.dfc.gov/Environment/EIA/forestfirst/Post_ESIA_Description_Status.pdf. Accessed March 16, 2023.

Forest Stewardship Council (FSC). 2023. FSC Connect: https://connect.fsc.org/impact/facts-figures. Forest Stewardship Council. Accessed November 28, 2023.

Forest Trends’ Ecosystem Marketplace. 2022. The art of integrity: state of voluntary carbon markets, Q3 Insights Briefing. Washington DC: Forest Trends Association.

Global Forest Watch. 2023. Monitoreo de bosques diseñado para la acción. Colombia, Incendios: https://www.globalforestwatch.org. Accessed March 16, 2023.

Google Maps. n.d. Map of Colombia. Available from: https://www.google.com/maps/place/Colombia/@4.5651674,-85.0224795,5z/data=!3m1!4b1!4m6!3m5!1s0x8e15a43aae1594a3:0x9a0d9a04eff2a340!8m2!3d4.570868!4d-74.297333!16zL20vMDFsczI?entry=ttu. Accessed November 25, 2023.

Guadua Bamboo. 2023. Finding perfect farmland in Colombia: https://www.guaduabamboo.com/blog/finding-perfect-farmland-in-colombia. Accessed March 16, 2023.

Herrera LP. 2021. Legal Guide to do Business in Colombia: https://investincolombia.com.co/sites/default/files/2021-10/legal-guide-to-do-business-in-colombia.pdf. Accessed March 16, 2023.

iContainers. 2020. Colombia’s top five ports: https://www.icontainers.com/us/2020/01/31/top-5-ports-colombia/. Accessed March 16, 2023.
Insituto Forestal. 2023. Inventario Forestal Nacional de Chile. Santiago, Chile: https://ifn.infor.cl. Accessed January 30, 2024.

International Tropical Timber Technical Association (ATIBT). 2023. Timber Trade Portal, Colombia: https://www.timbertradeportal.com/en/colombia/131/timber-sector. Accessed November 16, 2023.

Inverbosques. 2020. Resumen Publico, Plan de Manejo Forestal Sostenible 2020. Inverbosques. Colombia: https://www.inverbosques.com/wp-content/uploads/2021/10/20200430-RESUMEN-PUBLICO-PLAN-MANEJO-FORESTAL-INVERBOSQUES-2.pdf. Accessed March 16, 2023.

Korhonen J, Nepal P, Prestemon JP, Cubbage F. 2021. Projecting global and regional outlooks for planted forests under the shared socio-economic pathways. New Forests 52, 197–216 (2021). Accessed January 18, 2024.
https://doi.org/10.1007/s11056-020-09789-z

La Unidad de Planificación Rural Agropecuaria (UPRA). 2023. Sistema de información para la planificación rural agropecuaria (SIPRA). Ministerio de Agricultura y Desarrollo Rural (MARD). Bogotá, Colombia. https://sipra.upra.gov.co/nacional. Accessed on October 3, 2023.

Lopera G. 2022. Global timber template 2020. Provided by Fred Cubbage, personal communication. Used in Cubbage et al. (2022) (see above).

Madrigal C. 1993. La reforestación y su situación entomología en Colombia. In Proceedings: Conferência Regional da Vespa da Madiera, Sirex noctilio, na America do Sul, EMBRAPA, Colombo, Brazil, ppinus 59-64.

Medina J, Rodriguez C, Coronado M, Garcia L. 2021. Scoping review of thermal research in Colombia. Buildings. https://doi.org/10.3390/buildings11060232

Merle C, Octavio López Y, Castellanos FM, Valderrama M, Reyes P, Parrot I, Osorio JR. 2018. Estudios de economía forestal en el marco de la misión de crecimiento verde en Colombia, Resumen Ejecutivo. Gobierno de Colombia, Department Nacional de Planificaciòn.

Ministerio de Agricultura y Desarrollo Rural (MADR). 2006. Colombia: Un país de oportunidades para la inversión forestal. Bogotá, Colombia. https://repository.agrosavia.co/bitstream/handle/20.500.12324/18894/43943_55704.pdf?sequence=1&isAllowed=y. Accessed March 16, 2023.

MADR. 2013. Certificado de Incentivo Forestal - CIF 2013. https://www.minagricultura.gov.co/tramites-servicios/apoyos-incentivos/Paginas/v1/Certificado-de-Incentivo-Forestal-CIF-2013.aspx Bogotá, Colombia. Accessed on November 7, 2023.

MADR. 2015. Zonificación para plantaciones forestales con fines comerciales, escala 1:100,000. Memoría Técnica. Bogotá, Colombia: https://repository.agrosavia.co/handle/20.500.12324/12715. Accessed March 16, 2023.

MADR. 2020. Cadena forestal. Presentacion de marzo de 2020. Bogotá, Colombia. Available from: https://sioc.minagricultura.gov.co/Forestal/Documentos/2020-03-31%20Cifras%20Sectoriales.pdf.
Accessed February 9, 2024.

MADR. 2022. Boletín Estadístico Forestal No. 6, Septiembre 2022. Bogotá, Colombia: https://fedemaderas.org.co/boletin-estadistico-forestal-2022/. Accessed February 9, 2024.

MADR. 2023. Boletín Estadístico Forestal No. 7, Marzo 2023. Bogotá, Colombia: https://fedemaderas.org.co/wp-content/uploads/2023/05/07_BOLETIN_FORESTAL_DICIEMBRE_2022_WEB-comprimido.pdf. Accessed November 28, 2023.

Ministerio de Ambiente y Desarrollo Sostenible (MADS). 2016. Guía de exportación e importación de productos maderables. Bogotá, Colombia: https://www.minambiente.gov.co/wp-content/uploads/2021/10/Guia-Exportación-e-Importación-de-Productos-Maderables.pdf. Accessed March 16, 2023.

Ministerio de Ganaderia, Agricultura y Pesca. 2023. Superficie forestal de bosques plantados del Uruguay. Montevideo, Uruguay: https://www.gub.uy/ministerio-ganaderia-agricultura-pesca/datos-y-estadisticas/estadisticas/superficie-forestal-bosques-plantados-del-uruguay. Accessed March 16, 2023.

Mitula. 2023. Fincas, Colombia: https://casas.mitula.com.co/casas/fincas-colombia. Accessed March 16, 2023.

Nepal P, Korhonen J, Prestemon J, Cubbage F. 2019. Projecting global planted forest area developments and the associated impacts on global forest product markets. Journal of Environmental Management. 240. 421-430. Accessed January 24, 2024. https://doi.org/10.1016/j.jenvman.2019.03.126

Observatory of Economic Complexity (OEC). 2020. Papel de fibras de celulosa. OEC: https://oec.world/es/profile/bilateral-product/cellulose-fibers-paper/reporter/col. Accessed March 16, 2023.

Office National des Forets - Andina. 2018. Presentación del estudio sobre economía forestal. Sesión No. 7 Comité Asesor Estratégico, Misión de Crecimiento Verde. Bogotá, Colombia. https://www.dnp.gov.co/LaEntidad_/misiones/mision-crecimiento-verde/Documents/comite/Sesion%207/presentacion%20DNP%2001%2002%202018%20-%202.pdf. Accessed February 14, 2024.

OXFAM. 2017. Radriografía de la desigualdad: lo que nos dice el último censo agropecuario sobre la distribución de la tierra en Colombia. Bogotá D.C., Colombia. OXFAM-America: https://www.oxfam.org/es/informes/radiografia-de-la-desigualdad. Accessed March 16, 2023.

Pinzón-Florián, O. 2020. Pests management in Colombian forest plantations. In: Estay, S. (eds) Forest pest and disease management in Latin America. Springer, Cham. Accessed March 16, 2023. https://doi.org/10.1007/978-3-030-35143-4_10

Preferred by Nature. 2021. Informe de certificación de manejo forestal de evaluación de certificación Forest First Colombia S.A.S. (FFC) en el Departamento de El Vichada, Colombia: https://fscglobal.my.salesforce-sites.com/servlet/servlet.FileDownload?file=00P4y00001VkJAcEAN. Accessed March 16, 2023.

ProColombia. n.d. Commercial plantation forests: https://investincolombia.com.co/en/sectors/agricultural-products-food-production/commercial-plantation-forests. Accessed Feb. 21, 2023.

Puntopropiedad. 2023. Lotes de terrenos en venta en Puerto Carreño: https://www.puntopropiedad.com/venta/lotes-terrenos/vichada. Accessed March 16, 2023.

Reforestadora Integral De Antioquia. Medellín, Colombia. n.d. Sobre Nosotros: https://riaforestal.org/Sobre-nosotros/. Accessed March 16, 2023.

Reforestadora La Paz. 2022. Resumen plan de manejo forestal. Reforestadora La Paz S.A.S. Bogotá, Colombia: https://forliance.com/wp-content/uploads/2022/11/GFR-PL-002-Plan-de-Manejo-Forestal-PMF-Resumen-V3.pdf. Accessed March 16, 2023.

Rodas, CA 1998. Programa manejo de defoliadores en plantaciones forestales en Colombia. In Proceedings: Congresso Internacional de Plagas Forestales, August 18-21, 1997. Pucón, IX Region, Chile. pp. 141-149.

Rodas, CA, Wingfield MJ, Granados GM, Barnes I. 2015. Dothistroma needle blight: an emerging epidemic caused by Dothistroma septosporum in Colombia. Plant Pathol 65(1):53–63. Accessed on February 9, 2024. https://doi.org/10.1111/ppa.12389

Rodas, CA. 2023. Sanidad forestal en programas de mejoramiento y en viveros forestales. Presentation at the Conferencia Forestal, Julio 13-14, 2023. Bogotá, Colombia.

Registro Único Nacional de Áreas Protegidas. 2023. Parque Nacionales Naturales de Colombia. Bogotá, Colombia: https://www.parquesnacionales.gov.co/portal/es/sistema-nacional-de-areas-protegidas-sinap/registro-unico-nacional-de-areas-protegidas/. Accessed March 16, 2023.

Schneider KM. 2021. Colombia Government Flags: https://www.crwflags.com/fotw/flags/co_arg.html. Accessed March 16, 2023.

Segovia A. 2017. The relationships between food security and violent conflicts:
The case of Colombia. FAO Agricultural Development Economics Working Paper 17-06. ISSN 2521-1838. Available from: https://www.fao.org/3/i8339e/i8339e.pdf. Accessed February 9, 2024.

SGS South Africa. 2018. Informe de certificación de manejo forestal, Smurfit Kappa Cartón de Colombia – Reforestadora Andina S.A. Certificate No. SGS-FM/COC-001589. SGS South Africa. South Africa: https://fscglobal.my.salesforce-sites.com/servlet/servlet.FileDownload?file=00Pf300000t0WrEEAU. Accessed March 16, 2023.

Shell plc. 2021. Task force on voluntary carbon markets. Shell plc. Available from: https://www.shell.com/shellenergy/othersolutions/welcome-to-shell-environmental-products.html?utm_source=google&utm_medium=cpc&utm_content=textad&utm_campaign=US_EN_NB_EM_GGL_trading-and-supply_voluntary-carbon-credits&gclid=CjwKCAjw9-KTBhBcEiwAr19igw8UiaWLMvup02wDQSLBw9uwEIob21AtzCauR8T5HRhaeYTCLMRNZhoCROoQAvD_BwE .Accessed March 16, 2023.

Smurfit Kappa. 2022. Resumen del Plan de Manejo 2022-2026 de la División Forestal. Smurfit Kappa. Bogotá, Colombia. https://media.smurfitkappa.com/co/-/m/files/publications---country/colombia/informes-anuales-skcc/resumen-plan-de-manejo-forestal-2022-2026.pdf?rev=d4f35c4a1941464795d92f91d8382571.Accessed March 16, 2023.

Sociedad de Agricultores de Colombia (SAC). 2022. ¿Cuándo será la hora del sector forestal? Revista Nacional de Agricultura, Edición 1028 – Agosto 2022: https://sac.org.co/cuando-sera-la-hora-del-sector-forestal/. Accessed March 16, 2023.

The Colombian Information Site. 2015. Colombian Caribbean region. Available from: http://www.colombiainfo.org/en-us/colombia/regions/caribbean.aspx. Accessed March 16, 2023.

The Economist. 2023. Economic & Financial Indicators, Interest rates. Volume 449, Number 9370, Page 76. November 4, 2023.

Toro A. 2017. Mi pasión está en la reforestación comercial. Revista Fedemaderos. Abril de 2017. Edición 35. Bogotá D.C. ISSN 1909-0242. https://fedemaderas.org.co/wp-content/uploads/2017/05/fedemaderas_35PW.pdf. Accessed February 9, 2024.

Traffic. n.d. Colombia Briefing Document. FLEGT, WWF, IUCN, and the European Commission: https://www.traffic.org/site/assets/files/8617/flegt-colombia.pdf. Accessed March 16, 2023.

Transparency International. 2022. Corruption Perceptions Index: https://www.transparency.org/en/cpi/2021/index/col. Accessed March 16, 2023.

Travel Guide of Colombia. 2016. Map of Colombia Departments: https://www.colombiatravelguide.net/map-of-colombia-departments.html. Accessed March 16, 2023.

The United Nations Statistics Department. 2014. Country Profile – Colombia. Available from: http://data.un.org/en/iso/co.html. Accessed March 16, 2023.

USAID. 2017. Colombia – property rights and resource governance profile. USAID. Washington, DC. Available from: https://www.land-links.org/wp-content/uploads/2017/01/USAID_Land_Tenure_Colombia_Profile_Revised_December-2017.pdf . Accessed March 16, 2023.

The US Department of State. 2021. 2021 Investment climate statements, Colombia: https://www.state.gov/reports/2021-investment-climate-statements/colombia. Accessed March 16, 2023.

The US Department of State. 2023. Colombia Travel Advisory: https://travel.state.gov/content/travel/en/traveladvisories/traveladvisories/colombia-travel-advisory.html. Accessed March 16, 2023.

Verra. 2022. VCS Standards. Verra. https://verra.org/wp-content/uploads/2022/02/VCS-Standard_v4.2.pdf. Accessed March 16, 2023.

Verra. 2023. Registry for Colombia. Verra. https://registry.verra.org. Accessed November 28, 2023.

Vicary, BP. 2023. MAI, Sewall December 2022 Investor Survey, Sewall Forestry & Natural Resource Consulting. Sewall Forestry.

Wingfield MJ, Rodas C, Myburg H, Venter M, Wright J, Wingfield BD. 2001. Cryphonectria canker on Tibouchina in Colombia. Forest Pathology 31(5):297. https://doi.org/10.1046/j.1439-0329.2001.00248.x

World Bank. 2021. International Comparison Program, World Bank. World Development Indicators database, World Bank. Eurostat-OECD PPP Programme, Colombia: https://data.worldbank.org/indicator/NY.GDPINUSMKTPINUSCD?locations=CO. Accessed March 16, 2023.

World Bank. 2023. State and Trends of Carbon Pricing 2023. © http://hdl.handle.net/10986/39796 License: CC BY 3.0 IGO.” URI https://openknowledge.worldbank.org/handle/10986/39796. Accessed November 28, 2023

Wright JA, Isaza N. 1997. Silviculture and genetics of Pinus kesiya for planting degraded pasture land. Southern African Forestry Journal 179:1, 25-27. Accessed March 16, 2023. https://doi.org/10.1080/10295925.1997.9631150

Most read articles by the same author(s)