CONICET | Buscador de Institutos y Recursos Humanos

Forests are used for multiple purposes, generating conflicts between timber production and biodiversity conservation. A management approach modelled on natural processes that can reduce such conflicts is Variable Retention-VR. In Tierra del Fuego (Argentina), a portion of the original stand is left unlogged (30% as aggregated-AR and 15% as dispersed-DR retention) to provide continuity of structural and compositional diversity. Meta-analysis combines results of several studies that address a set of related research hypotheses, to synthetize the individual findings. Most of the studies are based on literature review, introducing biases due to differences in the sampling design, while long-term plots in forestry allowed generate large quantity of data bases with the same sampling design. The objective was to identify impacts and benefits of VR in the management of Nothofagus pumilio forests through the use of meta-analysis. Here, we describe a meta-analysis with 710 variables (113 types along the first 9 years-after-harvesting) of long-term plots analyzing the following comparisons for forest structure, reproductive, abiotic and biotic variables: primary forests-PF vs. AR, PF vs. DR, AR vs. DR, and AR/PF vs. DR/PF. For each comparison we used F and p values, where effect sizes were calculated through Fisher´s Z-transformation and using random-effect models with categorical data in the Metawin 2.1 software. Effect sizes for PF vs. AR were negative for forest and positive for other variables (mean effect size-MES 0.153). Effect sizes for PF vs. DR were negative for forest, non-significant for reproductive, and positive for other variables (MES 0.071). Finally, effect sizes for AR vs. DR and AR/PF vs. DR/PF were negative for forest and reproductive, and positive for other variables (MES -0.067 and -0.090, respectively). Greater changes were observed in the DR, while AR showed lower impacts maintained PF values.

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