Contents lists available at ScienceDirect Forest Ecology and Management journal homepage: www.elsevier.com/locate/foreco A 30-year study of the effects of selective logging on a stem-less palm (Astrocaryum sociale) in a central-Amazon forest Emílio Manabu Higashikawa ⁎ , Maria Marcela Ortiz Brasil, William Ernest Magnusson Coordenação de Pesquisas em Ecologia, Instituto Nacional de Pesquisas da Amazônia (INPA), CP2223, 69067-375 Manaus, AM, Brazil ARTICLE INFO Keywords: Selective logging Stem-less palm Understory Amazonia ABSTRACT We studied the long-term effects of different selective-logging intensities on the stem-less palm Astrocaryum sociale in a central Amazonian forest 90 km north of Manaus. The experiment consisted of three blocks of 24 ha, each divided into six 4 ha plots in which the treatments were allocated randomly. Each block had a control plot. Within each block, commercial timber was logged with intensities of 44%, 50% and 67% of basal area in 1987, 1988 and 1993 respectively. Stem-less palms in each plot were measured in 1996 and 2016. The number of individuals decreased slightly from 3229 in 1996 to 2997 in 2016, and there was an increase in the proportion of large palms. The degree of change in size structure was related to time since logging (p = 0.012), which also affected the total number of leaves (p = 0.0001), the sum of all leaf lengths (p = 0.01) and the number of adults (p = 0.056). The volume of timber extracted and in standing dead trees was not related to size-structure change. In the control block, the number of individuals changed slightly during the study period. As the different cutting intensities had little, if any, effect of the size-structure of this understory palm up to 30 years after logging, management concessions can contribute to the conservation of some elements of palm biodiversity. 1. Introduction Well-planned forest management can contribute to global biodi- versity conservation (Chaudhary et al., 2016). Reduced-impact logging (RIL) techniques are considered useful tools for decreasing the rate of tropical-forest deforestation (Darrigo et al., 2016; Putz et al., 2012; Schwartz et al, 2012), can produce more profit than conventional log- ging (Barreto et al., 1998; Boltz et al., 2001; Holmes et al., 2002, Johns et al., 1996) and purportedly guarantee wood for the next logging cycle (Holmes et al., 2002; Johns et al., 1996; Verissimo et al., 1992). There are many studies concerning the effects of RIL on regeneration of commercial trees (Darrigo et al., 2016; de Carvalho et al., 2017; Doucet et al., 2009; Karsten et al., 2013; Rivett et al., 2016; Schwartz et al., 2012, 2013; 2017; Soriano et al., 2011), but few studies of regeneration of species with little commercial value in selectively logged areas (Clark et al., 2001; Costa et al., 2002; Dekker and De Graaf, 2003; Magnusson et al., 1999) and fewer studies evaluating the effects of logging tech- niques on palms (Arevalo et al., 2016). Palms are an abundant and distinctive element in the central Amazon, found from sub-canopy to canopy, in all types of soil and to- pography and they exhibit a large range of growth forms (Kahn and Castro, 1985). The stem-less palm, Astrocaryum sociale, is endemic to the central Amazon region. It occurs on well drained, flat to slightly sloping areas (Kahn and Castro, 1985); the types of areas that are usually selected for logging. In these areas, stem-less palms are often the dominant component of the forest sub-canopy (Guillaumet, 1987; Kahn, 1986). Several studies have evaluated the effects of selective logging on commercial and non-commercial species in the Manaus region (Costa and Magnusson, 2003; Limaet al., 2002; Magnusson et al., 1999). However, there are no studies of the effects of selective logging on A. sociale. The aim of this study was evaluate the effects of different log- ging intensities on A. sociale in an area that was selectively logged in 1987, 1988 and 1993 (Higuchi et al., 1985). 2. Material and methods 2.1. Study site The study was carried out in the ZF2 Forest-Management Station (2°37′S latitude, 60°11′W longitude) of the Instituto Nacional de Pesquisas da Amazônia, 90 km north of Manaus, Brazil. The site is covered by terra firme dense tropical rainforest (Braga, 1979), with an average altitude of 124 m above sea level and undulating topography. The Bionte project was initiated in 1985 to evaluate the effects of dif- ferent intensities of basal-area reduction due to selective logging. The https://doi.org/10.1016/j.foreco.2018.10.003 Received 12 July 2018; Received in revised form 25 September 2018; Accepted 1 October 2018 ⁎ Corresponding author. E-mail address: emilio.higashikawa@gmail.com (E.M. Higashikawa). Forest Ecology and Management 432 (2019) 607–611 0378-1127/ © 2018 Elsevier B.V. All rights reserved. T