SEASONALITY OF THE BARK TANNINS CONTENT OF FIVE-YEAR-OLD Acacia mangium TREES GROWN IN NORTHEAST BRAZIL

Jaltiery Bezerra De Souza,Alexandre Santos Pimenta,João Gilberto Ucella Meza Filho,Tatiane Kelly Barbosa De Azevêdo,Bruna Rafaella Ferreira Da Silva,João Paulo Silva Gomes

doi:10.1590/1806-908820210000023

Abstract

ABSTRACT This study aimed to assess the influence of the seasonality on the bark tannins content of Acacia mangium trees grown in the Northeastern Brazilian Region and the effect of soil preparation on the results. Two experimental plots of 1.0 ha each were submitted to different soil preparation methods, with two different intensities. The experimental design consisted of four treatments, two types of soil preparation and, two different bark collection seasons (end of the rainy and dry seasons). The bark of the trees was collected in each treatment and the contents of condensed tannins were determined. For each experimental treatment, 15 trees were harvested and debarked. Bark material was submitted to extraction with hot water, obtaining the total solids content (TSC), Stiasny index (I), and the condensed tannins content (CTC). There was no influence of the soil preparation method on the TSC, I, and CTC. However, there was a significant difference in these parameters for tree bark collected in the rainy season, with higher values. The less intensive soil preparation method is recommended due to its lower cost, and bark should be collected at the end of the rainy season for the best yield of condensed tannins.

Highlights

Tannins have several industrial applications, such as plastic production, oil well drilling, water treatment (Nepomuceno et al, 2018), paint manufacture, wood adhesive production (Hoong et al, 2011; Zhou and Pizzi, 2014; Souza et al 2020) and manufacture of pharmaceuticals (Carvalho et al, 2018), including fungicides and products to kill cariogenic bacteria (Araújo et al, 2018)
Bark material was submitted to extraction with hot water, obtaining the total solids content (TSC), Stiasny index (I), and the condensed tannins content (CTC)
A. mangium is recommended to planting in agroforestry systems and for honey production (Oliveira, 2017)

Summary

Introduction

Tannins have several industrial applications, such as plastic production, oil well drilling, water treatment (Nepomuceno et al, 2018), paint manufacture, wood adhesive production (Hoong et al, 2011; Zhou and Pizzi, 2014; Souza et al 2020) and manufacture of pharmaceuticals (Carvalho et al, 2018), including fungicides and products to kill cariogenic bacteria (Araújo et al, 2018). In Northeastern Brazilian Region, tannins are used mainly for leather tanning (Paes et al, 2006). According to Paes et al (2006), other native tree species are potential sources of tannins in Brazil, such as Stryphnodendron adstringens (Mart.) Coville (barbatimão), Mimosa tenuiflora (Mart.) Benth. The last species is exclusively used to obtain tannins for leather tanning, but is threatened with extinction. It and Acacia auriculiformis are the two most planted species of this genus. A. mangium is grown in more than 600,000 hectares of planted forests in the world, providing wood as raw material for pulp and paper, low-cost furniture, civil construction, plywood, firewood and charcoal (Souza et al, 2010). The species has fast growth, low nutritional requirements, is tolerant of acidic soils and compaction, and has high nitrogen fixation rate

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