Floristics and Structure of Arboreal Components in a Restored Atlantic Forest Area

Background: Coffee and livestock degrade Seasonal Semideciduous Forests in the Zona da Mata region of the Atlantic Forest biome in Brazil. The oristic composition must be studied to preserve and conserve forest remnants. The objective was to evaluate the arboreal structure, characterize the seed dispersal syndrome and the ecological group of forest species of a 45-year-old restored area in Viçosa, Minas Gerais state, Brazil. The phytosociological parameters density, frequency, dominance and importance value, Shannon's diversity and Pielou's equability were evaluated considering individuals with DBH (diameter at breast height) ≥ 5 cm in sixteen contiguous plots (25 x 25 m). Results: A total of 1,323 individuals from 109 species and 35 botanical families were registered, of which 90 were native and 15 exotic species. The importance value (VI= 11.9%) was highest for Guarea guidonia (Fabaceae). The Shannon's diversity (H') was 3.46 and the equability (J') was 0.74. The number of species (33%) was largest for the initial secondary successional class and the number of individuals with zoochoric dispersion syndrome for the late secondary class (38.3%). The basal area was 44.1 m² ha -1 and the average height was 13 m (ranging from 2 to 32 m). Conclusion: The restored Semideciduous Seasonal Forest is in an advanced successional stage with zoochoric species and a great number of late secondary species.


Background
The Atlantic Forest in Minas Gerais state, Brazil includes different formations, with a predominance of seasonal semi-deciduous forests degraded by coffee and livestock (IBGE, 2012). Forest fragmentation increases the importance of restoring these areas to conserve biodiversity and establishing representative populations of regional native ora and genetic diversity (Braga et  Phytosociological analyzes allows to assess environmental impact for the sustainable use, conservation and restoration of the ecosystems (Durigan, 2009). The successional stages and interventions to recover a forest closer to a stage of balance are evaluated by analyzes of the oristics and structure of the arboreal component and in this study a reference area for comparison is used a lot, and whether the area is really restored or close to a natural area (Souza et  In addition, understanding the successional dynamics of a forest community in its different stages allows guiding its management (Pinto et al., 2007).  (Brancalion et al., 2015), allowing a better understanding of the restoration progress of areas as well as determining the period it takes to reach satisfactory values of naturalness, i.e., as close as possible to a natural ecosystem (Londe et al., 2020).
The objective was to evaluate the arboreal component and structure, characterize the seed dispersal syndrome and the ecological group of species of a 45-year-old restored area by planting in Viçosa, Minas Gerais stage, Brazil.

Study area
The study was carried out in a forest

Analysis of data
The sampled species were divided into successional categories as pioneers (P), initial (IS) and late (LS) secondary and the in the categories of initial, medium and advanced succession (Budowski 1965, Gandol et al., 1995. Species without ecophysiological information and not included in any of the categories were referred as non-characterized (NC). The species were also classi ed as anemochoric (Ane), autochoric (Auto) or zoochoric according to their seed spread syndrome (Zoo) (van der PIJL, 1982).

Floristic
A total of 1,323 individuals of 109 species (91 natives, 15 exotics and 3 uncharacterized) of 35 botanical families were recorded in the restored Semideciduous Seasonal Forest. A total of According to the ecological group, 25, 34, 35 and 15 species were P, IS, LS and NC, respectively, according to their ecological group (Table 1 -supplementary material). The exclusive species of the non-planted tree strata (regenerating) represented 56% of the total species sampled, being 51 natives, six exotics and four NC (Fig. 1). The IS species occupied 42%, 34.4% and 33% of the tree strata, non-planted ones and the total planted area, respectivelly. The proportion of individuals of those species planted was higher for the IS species (43.7%), and the individuals of the LS class prevailed in the non-planted tree strata (38.9%) and in the total area (38.3%) (Fig. 2).
The Zoo dispersion syndrome predominated with 58 species, followed by Ane and Auto syndromes with 28 and 16 species, respectively. Sixty-two species in the area were not planted in 1967 and 1969. The number of species and individuals with Zoo dispersion syndrome and the non-planted tree strata were higher, 48.6% and 52.1 species and 58.4% and 59.6% individuals, respectivelly. The Ane syndrome was found for 38,0% and 32.5% of for the planted species and individuals, respectively (Fig. 3).

Forest struture
The H' and J' indexes of the 45-year-old restored area were 3.46 and 0.74, respectively. The importance value of the Guarea guidonia and Archontophoenix cunninghamiana 4.7 and 1.6%, respectively (Fig. 4). However, the A. cunninghamiana was concentrated in a few plots.

Vertical and horizontal strati cation
The majority of individuals G. guidonia and A. cunninghamiana present in the restored forest are in diametric classes of 7.5, 12.5 and 17.5 cm in diameter (Fig. 5). The height of the trees ranged from 2 to 32 m with an average of 13 m. The height of Archontophoenix cunninghamiana was highest (32 m) followed by P. gonoacantha and A. peregrina, both up to 30-m height, G. guidonia with 28 m, L.

Discussion
The density of species sampled (1,323 individuals ha − 1 ) was higher than in a 9-year-old restored area a similar pattern between secondary forest plots and propagation sources. In addition, the higher species richness in older secondary than in primary forests is due to the coexistence of P and LS species (Bongers et al., 2009;Huston and Smith, 1987). This indicator of tree species richness in planted areas was similar to the reference areas present in the surroundings, showing that efforts have been made so that naturally diverse areas are restored from a large set of species, which is more e cient for permanent  (Tang et al., 2020). The high J' was similar to that in a well-preserved vegetation fragment in a Seasonal Semideciduous Forest representative of the original condition in the Uberaba, Minas Gerais state (J '= 0.73) (Dias Neto et al., 2009) and higher than that of restored areas (J'= 0.89) (Colmanetti and Barbosa, 2013). The oristic results in the Semideciduous Seasonal Forest area were similar to the present study but factors such as succession stage, degree of disturbance and site characteristics can affect them (Gonçalves and Souza, 2014). The highest VIs of G. guidonia and A. cunninghamiana was due to the diametric distribution in the inverted J-pattern, i.e., a large number of individuals in the smaller diameter classes and that G. Guidonia being an LS species and well adapted to shaded environments (Lorenzi, 2002). The current intermediate-advanced succession stage of the study area allowed the propagation and development of this species, which did not occur in the initial successional stage after planting. In addition, G. guidonia takes longer to enter reproductive age because it is an IS (Lorenzi, 2002). Archontophoenix cunninghamiana is an exotic and invasive species in the understory of forest fragments or mature restored forests and this palm coexists with other native species tolerant to shade (Dislich et al., 2002;Miranda Neto et al., 2012). The presence of this species in a high-density value in a few plots makes an imbalance distribution of this species in the area. The lower number of shade-tolerant exotic species compared to that of heliophytes increases the impact of the rst species threatening best-preserved environments and the conservation value (Martin et al., 2009).
The average height of arboreal individuals was greater than that of a forest fragment in good conservation stage in the Minas Gerais state (Campos et al. 2006). The average tree height greater than 12 m represents forests in advanced succession stage in the Atlantic Forest of the Minas Gerais state (CONAMA Resolution 392/2007) and its structural diversity shows a succession stage as found for primary forests. This is due to the establishment of multilayer strata at early stages of forest vegetation development, allowing the forest system to e ciently use nutrients, light, water and other resources

Conclusions
The restoration of Seasonal Semideciduous Forest provided conditions to regenerating regional native species with a predominance of those with initial secondary successional zoochoric dispersion syndrome. The low frequency of pioneer species shows the progress of the restored area. Secondary forest succession is a viable and e cient strategy in fragmented environments and modi ed landscapes, as it increases forest coverage and the conservation of the biodiversity and ecosystem services. Availability of data and materials: The datasets analyzed during the current study are available from the corresponding author on reasonable request.
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Declaration of Competing Interest:
The authors declare that they have no know competing nancial interests or personal relationships that could have appeared to in uence the work reportaded in this paper.