Contents lists available at ScienceDirect Forest Ecology and Management journal homepage: www.elsevier.com/locate/foreco Clonal composites: An alternative to improve the sustainability of production in eucalypt forests Gabriel Dehon Sampaio Peçanha Rezende a, ⁎ , José Luis Lima a , Donizete da Costa Dias a , Bruno Marco de Lima a , Aurélio Mendes Aguiar a , Fernando de Lellis Garcia Bertolucci a , Magno Antônio Patto Ramalho b a Fibria Celulose S.A, Brazil b Federal University of Lavras, Brazil ARTICLE INFO Keywords: Eucalypt sustainable plantations Eucalypt breeding Clonal deployment Clonal composites Clonal mixtures ABSTRACT The use of eucalypt clonal composites framed by improved, phenotypically similar and unrelated clones may be an important strategy to help breeders prevent commercial eucalypt plantations from unpredictable future ad- verse events, as well as to promote sustainable productivity gains. The present study was conducted to test this hypothesis by comparing the growth (MAI) at ages three to four years of a significant number of clones in clonal composite (CC) and monoclonal (MC) typologies under distinct environmental conditions, both at experimental and commercial scales. The CC presented MAI performance superior to MC in both experimental (9.8%) and commercial (6.3%) conditions. In each region, different clones respond differently to allo (CC) and auto-com- petition (MC), but most of them (73%) performed better in CC. Furthermore, CC commercial plantations pre- sented growth uniformity, at different ages, similar to MC plantations, as well as lower genetic vulnerability given by the proportion of replanting before the end of the rotation age due to biotic or abiotic damage agents. 1. Introduction The contribution of breeding programs to eucalypt productivity in Brazil, especially in the pulp and paper business, is unquestionable. This success is mostly due to the identification of adapted species and pro- venances, and to interspecific hybridization programs (e.g. E. grandis × E. urophylla) with further selection of the best individuals for clonal deployment (Ferreira and Santos, 1997; Assis and Mafia, 2007; Rezende et al., 2014). In Brazil, the use of monoclonal stands (MC) on a commercial scale began in the 1980s. Currently, this model is widely employed in many other countries, such as China, South Africa, Por- tugal, Spain, Chile, Argentina, and Uruguay. Forest companies gen- erally report that, historically, the employment of clonal plantations has provided at least a 25% gain in wood volume per hectare compared to seedling plantations established in the same locations, under the same management systems (Rezende et al., 2014). This advantage is mostly explained by the fact that cloning superior individuals allows full uti- lization of all kinds of genetic effects (additive and non-additive), which does not happen when using seeds produced from superior parents, regardless of their improvement level. The primary objective of any eucalypt breeder is to recommend new clones that are better than the preexisting ones. This is an enormous challenge, given that the best clones are recommended in the present, based on cumulative information from the past, aiming at future per- formance under different environmental conditions. This challenge is becoming even more important with the growing evidence on climate changes in recent decades. The use of clonal composites (CC), here defined as “mixtures of improved, phenotypically similar, genotypically distinct clones”, for the establishment of commercial stands, instead of the traditional mono- clonal (MC) approach, is a possible alternative to reduce breeders’ uncertainty regarding future conditions and to mitigate the genetic vulnerability of plantations to biotic and abiotic stresses. A greater in- trinsic genetic diversity of commercial plantations may contribute to attenuate the growing risks associated with new pests and diseases, to improve the plantations adjustment to climatic fluctuations (home- ostasis or phenotypic stability), and to promote a better balance in the use of the environmental resources. These hypothesis are supported by several studies conducted with both natural populations and commer- cial crops (National Academy of Science, 1972; Vellend, 2006; Bruzi et al., 2007; Boyden et al., 2008; Botelho et al., 2011; Forrester and Smith, 2012; Keneni et al., 2012; Fu, 2015; Soares et al., 2016; https://doi.org/10.1016/j.foreco.2019.06.042 Received 26 November 2018; Received in revised form 15 June 2019; Accepted 29 June 2019 ⁎ Corresponding author at: Rua Afonso César de Siqueira, 101/201C, Vila Adyana, São José dos Campos, SP CEP 12243-710, Brazil. E-mail address: grezende@bracell.com (G.D.S.P. Rezende). Forest Ecology and Management 449 (2019) 117445 0378-1127/ © 2019 Elsevier B.V. All rights reserved. T