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Adisnei Barzotto Ribeiro

Forestry Harvesting Manager at Tanac


Harvesting and mechanization for black wattle

The Acacia genus belongs to the Fabaceae family . There are around 1,350 species of Acacia found across the world and around 1,000 of those are found in Australia. Most species are short-lived, about 10 to 15 years. The main species planted in the world are Acacia mangium , Acacia saligna and Acacia mearnsii , the main planting countries being South Africa and Brazil, where it arrived around 1918.

Showing characteristics in its wood indicated for firewood, charcoal, cellulose, paper, wood panels, among other indications, Acacia can constitute a promising alternative for forestry, although it presents a smaller volume of wood produced per hectare when compared to other forests. cultivated. The possibility of multiple uses has always kept the species as an economically viable option, including for small producers, allowing income diversification on the property.

The Acacia mearnsii (Black Acacia) stands out in southern Brazil for presenting specific characteristics and is historically recognized for the quality of its bark, from which vegetable extracts are obtained, rich in tanning agents and phenols, compounds for the most diverse purposes.

Tanac , a Brazilian company created in 1948 in Rio Grande do Sul, is a world leader in the production of Black Acacia plant extracts, chips and pellets . A reference in sustainability, based on its strategy for environmental, social and governance practices, it conducts activities in a responsible manner, minimizing impacts on the environment and promoting socioeconomic development in the communities in which it operates.

Tanac products are sold in more than 60 countries on all continents, being present in the most varied industrial processes and day-to-day applications. The bark of the tree is the main source of tannin extraction, with the most diverse applications: leather tanning, oil and grease separation, effluent treatment, animal nutrition and other specialties. Wood chips are produced for cellulose and pellets for renewable energy generation.

The supply guarantee for the Tannins and Chips units starts at the Florestal unit, Tanagro , which is present in more than 20 municipalities in Rio Grande do Sul and supplies the manufacturing units with raw material, bark and wood, through the best practices, with sustainable and responsible forest management. In addition, the company has long-standing partnerships with producers, which guarantee the supply of raw materials and encourage the perennial cultivation of the species.

The Black Wattle harvest predominantly occurs between 6 and 10 years after planting, considering 7 years as the ideal age due to the concentrations and better quality of the tannin content contained in the bark. The particularity recognizable by the use of the bark as an important economic product, associated with the morphological characteristics of this species, mainly the tortuosity of the stem and concentration of branches, means that the harvest requires certain care and special attention, imposing some challenges in the implementation of a harvest and peel 100% mechanized. In this way, this species differs from other forest crops, such as eucalyptus and pine, in which the primary product is wood, and the bark is treated as a by-product or waste disposal.

For many years, due to the reduction of its market value, Acacia wood was considered a secondary product; on the other hand, the bark has become a great commercial attraction.

Due to the lack of mechanized debarking equipment that met specific requirements, manual work was encouraged in the short log harvesting and debarking operations, resulting in better use of the bark and causing the postponement of the mechanization process.

In 2002, with the increase in production scale and its manufacturing demands, associated with concern for the safety of its employees and shortage of manpower, Tanac carried out the first works related to the mechanization of forest harvesting in Acácia Negra in Rio Grande do Sul. That same year, keeping the focus on the maximum use of the bark, in the best conditions to meet the manufacturing requirements, the harvest began to be carried out experimentally by harvesters of 20 tons, with debarking heads, which was a great challenge in its implementation.

At the time, the production system of short logs was adopted, which was possible thanks to advances in partnerships with companies in the sector, enabling equipment that was suitable for harvesting Black Acacia and processing it.

After a period of carrying out the mechanized felling, delimbing , fractioning and debarking process, a reduction in the use and quality of the bark was observed , which generated many efforts to maintain the factory service levels compared to manual extraction, involving large number of people in post-barking to collect the bark and pack it optimally, which resulted in a retrogression to the previous model .

Later, gains in productivity were achieved with the maintenance of the harvester in the harvest and with the introduction of mobile peelers with rings, adapted with cranes to carry out the peeling. In this operation, the harvester provides the fractionated wood with bark in eitos, where the debarker performs the debarking procedure and packs the bark in bags ; thus facilitating subsequent transfer and maintaining characteristics similar to the manual method, avoiding loss of product quality.

Recently, several improvements and adaptations in the process have also brought significant gains in productivity and safety in operations. Different tests of wood cutting lengths were carried out in the mechanized harvesting system, in addition to debarking methodologies and alternatives, always seeking to maintain quality and gains in production scale.

With the advancement in solutions for the energy market, also envisioning the optimization of the harvesting process and the sustainability of operations, the use of black wattle residue (coivara) has been analyzed as an alternative source of biomass, with high calorific value. In this way, the integration of wood, bark and coivara products tends to provide a new advance in the Black Wattle harvest.

Tanac has been studying opportunities to adapt the whole tree harvesting system in its operations with Acacia, allowing whole trees to be dragged and processed at the edge of stands, optimizing the transfer of the three products, in addition to increasing the safety of operations in sites with controlled lands.