Commercial Logging of Timber Species Enhances Amazon (Brazil) Nut Populations: Insights from Bolivian Managed Forests

Marlene Soriano,Juan Carlos Licona,Frits Mohren,Cristina Barber,Nataly Ascarrunz,Pieter A Zuidema,Marielos Peña-Claros

doi:10.3390/f12081059

Marlene Soriano, Juan Carlos Licona + Show 5 more

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https://doi.org/10.3390/f12081059

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Abstract

A typical case of multiple-use forest management (MFM) in Southwestern Amazon is the commercial harvesting of Amazon or Brazil nut (Bertholletia excelsa) seeds and of timber of other tree species. Although the Amazon nut is the most important non-timber forest product (NTFP) in the Amazon basin, the species is under serious threat due to deforestation and may also be affected by overharvesting. However, selective logging of other tree species coexisting with Bertholletia may positively affect Bertholletia populations, thus enabling a special case for MFM. For this research, we investigated the impact of the intensity of Amazon nut harvesting and timber logging on Bertholletia populations in the Bolivian Amazon. We used demographic data from 72 two-hectare transects located within 24 community-based household forests varying in the intensity of nut collection (0–100%) and timber logging (0–15% of logging-disturbed forest area). Simulated Bertholletia population size increased with logging intensity but decreased with Amazon nut harvesting intensity. Bertholletia populations were projected to grow at the average MFM harvesting scenario tested: 57.4% of nut harvesting, 5.3% of logging-disturbed area (λ100 = 1.011). Our simulations also revealed that up to 89% of Amazon nut seeds can be harvested while sustaining Bertholletia populations, under 15% of logging-disturbed area, and applying liana cutting. Modest levels of timber logging and application of liana cutting may compensate for the negative effect of Amazon nut collection on Bertholletia populations for the next century. Our study demonstrates that Amazon nut and timber production could be combined in a sustainable MFM scheme, thus increasing the economic value of managed tropical forests and its promotion to reduce the increasing pressure by deforestation.

Highlights

We found that the effect of Amazon nut harvesting, logging, and liana cutting intensities on Bertholletia vital rates varied with Bertholletia size, especially when it came to growth and reproduction (Table 1)
Simulated liana cutting of 21% and 90% of the reproductive Amazon nut trees allowed for an increase of 15% and 4.5% of Amazon nut harvesting intensity under the average logging disturbance intensities of 5.3% and 15%, respectively; the provided population growth rates were above 1 (Figure 2)
Bertholletia growth of liana cuttingdisturbance on the fruit intensity production played aseedling key role in Bertholletia population rate and of liana growth cutting rate on the fruit production rate played a key role in Bertholletia pop- more intensely after 100 years. This implies that Amazon nuts can be harvested ulation growth rate after years

Summary

Introduction

Multiple-use forest management (MFM) entails the provision of multiple goods and services within a forest management unit area [1,2]. It has the potential to ensure the conservation of tropical forests in the face of increasing demand for food, changing land access rights, and trends in markets [2,3,4]. Harvesting of Amazon nut (Bertholletia excelsa, Lecythidaceae) seeds (considered a superfood) and timber of other tree species is a common market-oriented multiple use practice among rural communities in a significant part of the Bolivian, Peruvian, and Brazilian Amazon. Amazon nut harvesting contributes to household income in the range of 12–71% [5]. Bolivia’s export of Amazon nuts represents 25% of global exports and a third of it ends in EU markets [6]

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