From the end of the 1980s and beginning of the 90s, demands and forest restoration projects began to emerge, initially aimed at recovering riparian forests from water reservoirs. In common, these first forest restoration projects, which were undoubtedly extremely important for the development of the science and practice of forest restoration in Brazil, used concepts and techniques from traditional forestry.

Most of these pioneering projects took as base and theoretical foundation, the classic paradigm of succession, seeking to reproduce a final stage, that is, the climax of ecosystems, with the planting of species that occur in forests at an advanced stage. To achieve this, everything needed to be very predictable and in a certain way “plastered” with many rules and standardized definitions of spacing, number of species, etcetera.

Following the advancement of research into ecological succession, forest restoration began, in the last two decades, to gain a more flexible connotation, following the contemporary paradigm in which the important thing is to guarantee the advancement of the process, the gain of diversity over time, the recovery of ecosystem functions and the exploitation of its potential for self-recovery or resilience.

In this new approach to forest restoration, natural regeneration has passed and is being increasingly valued in projects, aiming not only to reduce the high costs of implementing and maintaining reforestation with planting in a total area, but also seeking to imitate the ecological processes that guarantee the natural advancement of ecological succession.

It is worth highlighting that in the context of large-scale restoration, such as large projects that involve restoration at the level of landscapes and even territories, a heterogeneity of situations is normally found, from areas with high potential for natural regeneration, in which the simple enclosure is sufficient for the return of the forest, even areas of low resilience pastures, occupied by aggressive exotic grasses such as brachiaria (Urochloa decumbens) and with remnants of native forests that are absent or very isolated and degraded, in which planting seedlings in an area is the best option.

Between these two extremes there are intermediate situations, in which it is more viable to adopt assisted natural regeneration, in which actions to stimulate natural regeneration are applied, such as crowning and covering fertilization of regenerants in pastures, the implantation of seedling cores and seeds, the control of invasive species that inhibit succession, among others.

In this current scenario of forest restoration, in the projects we develop at the Forest Restoration Laboratory at the Federal University of Viçosa, we always seek to make actions more flexible, directing more appropriate techniques for each situation of degradation and regeneration potential.

In the context of mining, as an example of the application of both natural regeneration and assisted natural regeneration and planting in a total area, we can mention the large project of the Renova Foundation in the Doce river basin, which has a partnership with the Forest Restoration Laboratory of Federal University of Viçosa in research and technical guidance.

In this, which is one of the largest large-scale forest restoration projects in Brazil, different scenarios were identified based on soil use and regeneration potential, making it possible to precisely define the areas destined for planting in the total area, as well as those in that natural regeneration alone or its conduction (Assisted Natural Regeneration) are sufficient.

A similar situation, which also has a partner with the Forest Restoration Laboratory, is Vale's large forest restoration program in areas affected by waste and compensation areas in Brumadinho, Minas Gerais, in which we contribute with research into monitoring the forest restoration of plantings in the total area, but also with nucleation techniques such as topsoil transposition and natural engineering techniques or soil bioengineering, via revegetation experiments on the banks of the Paraopeba River, with the planting of living cuttings.

Still in mining, it is worth highlighting the research and innovation initiatives carried out by Companhia Brasileira de Alumínio, in the Zona da Mata of Minas Gerais, in partnership with the Forest Restoration Laboratory since 2011. Through this major project, we have carried out research to monitor the forest restoration carried out by the company, both in mined areas and in compensation areas, using various indicators, such as natural regeneration, soil fertility, biodiversity of flora and fauna, analysis of forest cover through images, among others.

Furthermore, several innovations have been produced over these 12 years of partnership, with emphasis on the planting of tall seedlings (with an average height of 2 meters) on a large scale, which has enabled the rapid formation of canopies and soil coverage, overcoming the competition with brachiaria and reducing maintenance costs, in addition to promoting the attraction of fauna, since many seedlings are already planted with flowers and fruits.

As an example of a successful case with the application of assisted natural regeneration and other alternative techniques, we can mention the important forest restoration project carried out by CMPC Celulose Riograndense, in which the Forest Restoration Laboratory has also contributed since 2012. In this project, which involves forest gardens of the company in different regions of Rio Grande do Sul, the CMPC Florestal Restoration Laboratory partnership made it possible to convert the forest restoration system from planting in a total area to the planting of seedling cores, which resulted in a significant reduction in costs and in the occupation of Permanent Preservation Areas for regional native species in a few years.

In this partnership, we also took the seedling rescue technique to Rio Grande do Sul, which we were already using in Minas Gerais in projects with mining companies. Thus, currently almost all of the seedlings of native species in the centers implemented in the Permanent Preservation Areas by the company come from the rescue of seedlings from the understorey of eucalyptus plots.

Therefore, we can conclude that the forest restoration of mined areas, Permanent Preservation Areas and compensation areas should not be “tied” to a single technique, as there is a menu of different options, and decision-making must take into account several aspects, such as the state of degradation, available financial resources, local resilience and landscape level, among others.