Evaluation of the Sustainability of Reforestation Initiatives in Anthropized Forest Habitats in the Lubumbashi Charcoal Production Basin (Haut-Katanga, Dr Congo)

1. Introduction

Forests are terrestrial ecosystems harboring exceptional biodiversity [1]. They are home to 80% of the Earth's biological diversity and numerous endemic plant and animal species [2]. As a result, they play an important role in the sequestration of atmospheric carbon and contribute to the survival of both rural and urban populations through the ecosystem services they provide, such as dendro-energy and various non-timber forest products [3].

These forests cover almost 4.1 billion hectares, or 31% of the planet's land surface [4]. In Africa, forests represent around 675 million hectares [5,6], of which almost 12% is covered by miombo [7,8], a forest dominated-by woody species of the genera Brachystegia, Julbernardia and Isoberlinia [9,10]. This forest covers between 2.7 and 3.6 million km² of the Zambezi ecoregion [11], providing a livelihood for over 100 million people in both rural and urban areas [12,13]. In addition, this forest harbors significant biodiversity with a high rate of endemism, making it a priority for conservation [14,15].

However, increasing anthropogenic pressure on miombo is leading to deforestation and forest degradation [16-18]. The main factors are shifting agriculture and dendro-energy production [19, 20], to which are added timber exploitation and repeated bushfires, contributing to forest loss [21-23]. Thus, the deforestation rate of miombo varies from 2% to 22% in the Zambezi region, reaching high levels in countries where populations are highly dependent on forest resources [24], such as the Democratic Republic of Congo.

Indeed, in the Democratic Republic of Congo, a country with high forestry potential, the annual deforestation rate is the highest in the Congo Basin, at almost −0.4% between 2001 and 2019 [3]. Southeastern Democratic Republic of Congo, where miombo is dominant, has not been spared: its cover fell from over 70% of Katanga in 2000 to 43% in 2010 [25]. In the Lubumbashi Charcoal Production Basin – the administrative areas that supply the city of Lubumbashi with dendro-energy−, the deforestation rate is 1.51%, six times the national average [20], due to the poverty of rural and urban populations [26] and a difficult socio-economic context [27]. Combined with population growth and urbanization, this overexploitation is extending the deforestation of miombo, threatening the survival of dependent populations [2].

To combat deforestation and forest degradation, forest cover restoration is a key solution [8,28]. This process aims to restore the structure, composition, and ecological functions of forests, essential to the survival of communities in anthropized habitats [29]. Natural regeneration, a sustainable alternative, is effective in habitats with a high restoration capacity, dependent on disturbance and the resilience of woody species [13,30,31]. In cases of low resilience, reforestation is crucial to rapidly restore forest cover and ecosystem services [32,33], as in the Lubumbashi Charcoal Production Basin.

However, successful reforestation requires the involvement of local communities in project management, particularly in the selection of habitats and tree species [27,34]. Their involvement facilitates the acceptance and appropriation of reforestation programs, thus contributing to the sustainable management of natural resources [35,36].

Furthermore, several studies emphasize the importance of involving local communities in reforestation projects in Africa [6,37], particularly for the choice of woody species and the management of reforested habitats [38-40]. However, in the Zambezi region [41-43] and the Democratic Republic of the Congo [32,44], studies demonstrate this importance without delving into other aspects of the reforestation process that can lead to its success. In the Lubumbashi region, research on reforestation is limited. Although, studies highlight the need for reforestation in response to deforestation and emphasize the importance of integrating local communities into these processes [45-47], they do not specifically address the importance of this integration. This study fills this gap by showing that the involvement of local communities is crucial to the success and sustainability of reforestation projects. Integrating endogenous knowledge and local perceptions into these programs fosters sustainable involvement in natural resource management [24,32].

Thus, the present study aims to assess the sustainability of reforestation activities carried out in anthropized miombo habitats in the Lubumbashi Charcoal Production Basin. It tests the hypotheses that (i) reforested habitats and tree species were selected concertedly by the various stakeholders, attesting to an inclusive approach. Additionally, community-based planning, maintenance, monitoring, and evaluation practices ensure the sustainability of reforested habitats; (ii) the density/ha, mean square diameter, basal area, and floristic diversity of reforested habitats are statistically equivalent to those of unexploited miombo, because reforested habitats have been set aside to allow the forest cover to be reconstituted, and (iii) there are significant similarities/dissimilarities between the ethnobotanical and floristic lists, due to the varying levels of anthropogenic disturbance experienced by each habitat and the limited diversity of woody species used for reforestation.

2. Materials and Methods

2.1. Study Environment

The present study was carried out in the Lubumbashi Charcoal Production Basin in Haut-Katanga province, Democratic Republic of the Congo (Figure 1). This basin is situated at an altitude between of 1,200 and 1,300 m and at 11° 40'S - 27° 29'E. According to Koppen's classification system, the climate prevailing in this Lubumbashi Charcoal Production Basin is of the Cw type [48], characterized by two seasons including a rainy season (November to March), a dry season (May to September), separated by two transition months (April and October). Average annual rainfall is 1,270 mm, and average annual temperature ranges from 17 to 26°C [9,10].

In the Lubumbashi Charcoal Production Basin, the primary vegetation is miombo, which is gradually being replaced by savannah, particularly around built-up areas, due to human activities [16,20]. The soils in this region are ferralsols with poorly differentiated horizons [49]. The population of the Lubumbashi region remains highly dependent on natural resources, particularly though slash-and-burn agriculture and dendro-energy production [27]. Moreover, most of this population lives on less than $1.25 a day, expressing a high level of poverty, food insecurity, and deprivation [26].

2.1. Methods

2.2.1. Village Areas Selection and Sampling

To assess the effectiveness and sustainability of forest cover restoration activities, two village areas (Milando and Mwawa) in the Lubumbashi Charcoal Production Basin were selected. These village areas were identified as having intense anthropogenic activities, notably agriculture and charcoal production [27]. In addition, Milando and Mwawa benefited from reforestation activities initiated in 2018 as part of the implementation of forest concessions for local communities (FCLC). These activities involved the participation of several categories of stakeholders, including local communities, NGOs (APRONAPAKAT: Action pour la Protection de la Nature et des Peuples Autochtones du Katanga; BUCODED: Bureau Conseil en Développement Durable), the provincial environment coordination and the FAO (Food and Agriculture Organization of the United Nations). In these village areas, 100 individuals, 50 per village area, were selected for ethnobotanical surveys using the snowball method [50,51], between August 3 and September 15, 2024. This number was determined due to the lack of official statistics concerning individuals familiar with reforestation issues in both village areas.

2.2.2. Data collection

Ethnobotanical surveys were carried out using a semi-directive method [52], enabling the participants' discourse to be guided by pre-defined themes [53]. These surveys made it possible to gather qualitative data on the involvement of local communities in reforestation activities, particularly concerning the choice of habitats and woody species for reforestation, as well as the management activities of these habitats (Supplementary material). Forest management refers to all technical and practical actions aimed at preserving, restoring, and sustainably exploiting forests, including planning, reforestation, biodiversity monitoring, fire control, and conservation [54]. The identification of woody species cited under their vernacular names during these ethnobotanical surveys was carried out using existing floras (Flora of Zambia, Flora of Zimbabwe, World Flora) and identification manuals [9,55-57]. Field trips with some of the respondents also enabled to identify species cited and described in the local language, particularly those whose identification was difficult through the manuals.

Additionally, floristic inventories were carried out in reforested habitats and unexploited forests in each village area. Unexploited forest refers to miombo never exploited on a human scale for agriculture and charcoal production [20]. To this end, 40 floristic inventory plots were randomly installed, 20 in Milando village area (10 in reforested habitat and 10 in patches of unexploited forest) and 20 others in Mwawa. Plot dimensions were determined based on previous studies [58,59] which had shown that 50 m x 20 m (1000 m²) are adequate dimensions for floristic studies in miombo [13,59]. In these plots, all woody individuals with a diameter at breast height (DBH) ≥ 10 cm were counted and measured using forest tape [60]. These data on individual diameters allowed the establishment of the diameter structure of each inventoried habitat, while the counting enabled the calculation of individual density per unit area (hectare; [61]).

2.2.3. Data analysis

To determine the criteria used when selecting habitats and woody species for reforestation, the citation frequency (C_f; Equation (1); [62]) was calculated with the ethnobotanyR package under R software version 4.3.2, based on individual interviews. This frequency is based on the principle that the most frequently cited criteria directly influence the choice of habitats and species for reforestation. It is calculated by the equation:

$${\mathrm{C}}_{\mathrm{f}}={\displaystyle \frac{S}{N}}\times 100$$

(1)

where s represents the number of respondents citing the criterion and N, the total number of respondents. If C_f approaches 0, the criterion had little influence on the choice, while an C_f close to 100 indicates a strongly favored criterion.

Furthermore, to characterize and compare reforested and unexploited habitats in both village areas, several indicators were calculated: the diametric structure of inventoried individuals, density per hectare (N; Equation (2)), and the importance value index (IVI; [13,58]). The diametric structure reveals forest composition and dynamics, possibly indicating tree growth and the effects of environmental disturbances [61]. Density measures the number of individuals per hectare, while relative density reflects the proportion of a woody species within the habitat [62].

$$N={\displaystyle \frac{n_i}{a}}$$

(2)

where n_i is the number of individuals of a wood species on a plot and a is the area of the plot expressed in a hectare.

Additionally, the IVI assesses the ecological dominance of woody species, with a higher value indicating greater ecological significance of the species within the forest ecosystem [59,63]. This index is calculated by the following equation (Equation (3)):

$$IVI=\mathrm{R}\mathrm{D}\mathrm{o}+\mathrm{R}\mathrm{D}+\mathrm{R}\mathrm{F}$$

(3)

where RDo represents relative dominance (Equation (4)), while RD and RF correspond to relative density and frequency (Equations (6) and (7), respectively).

Relative dominance measures the basal area occupied by all individuals of a species over a hectare. However, relative density expresses the proportion of individuals of a species about all individuals in the habitat, while relative frequency indicates the proportion of a species out of wood species [58,59].

$$RDo={\displaystyle \frac{g_{i}sp}{g_{i}Tsp}}\times 100$$

(4)

where g_isp is the basal area of a species and g_iTsp, the sum of all basal areas of all woody species inventoried. However, g_i, the basal area of each individual measured (expressed in m²/plot area), is calculated using the equation below (Equation (5)):

$$g_i={\displaystyle \frac{\pi D^2}{4}}$$

(5)

with D, the diameter at breast height (DBH) of an individual, measured at 1.30 m from the ground.

$$RD={\displaystyle \frac{n_i}{N}}\times 100$$

(6)

where n_i is the number of individuals of a species and N is the total number of individuals surveyed.

$$RF={\displaystyle \frac{f}{F}}\times 100$$

(7)

with f the frequency of a woody species (Equation (8)), expressing the probability that a woody species occurs in each of the installed floristic inventory plots (surveys), and F the sum of all frequencies.

$$f={\displaystyle \frac{n}{Np}}$$

(8)

where n is the total number of plots where the species was surveyed, and Np is the total number of plots.

However, mean square diameter (DBH_m, Equation (9)) and basal area (GBA, Equation (10)) were calculated. The mean square diameter, expressed in cm, is used for trees with several trunks at 1.3 m height. In this study, DBH_m was used to determine the mean diameter of trees in both reforested and unexploited habitats. The basal area, a common metric in forest management (expressed in m²/ha), represents the cross-sectional area of tree trunks measured at breast height (1.3 m) [61,64]. In addition, the averages of species, genera, and families of individual trees inventoried in each habitat were calculated [64].

$${DBH}_m=\sqrt{{\displaystyle \frac{1}{n}}{\sum }_{i=1}^n{d}_i^2}$$

(9)

where di is the diameter at breast height (DBH) of each tree trunk or branch, measured at 1.3 m above the ground, and n is the total number of such trunks or branches measured.

$$GBA=FE{\sum }_{i=1}^m{g}_i$$

(10)

with m being the number of woody individuals inventoried in the plot, and FE the extension factor related to plot area (m²), used to extrapolate g_i values to the hectare [61].

To highlight statistical differences at the 5% significance level among the parameters characterizing these two habitat types, the non-parametric Kruskal-Wallis's test [65] was applied to density/ha, means square diameter, basal area, and floristic richness. This test was used given the non-normality of the data confirmed by Shapiro's test [66]. In the case of significant differences, the Dunn-Bonferroni post-hoc test enabled pairwise comparison of means [67,68].

To compare floristic diversity between the reforested and unexploited habitats, the Shannon, Simpson, and Piélou indices were calculated from floristic inventory data [2]. The Shannon index assesses specific heterogeneity and the distribution of individuals between species, while Simpson measures the probability of encountering two individuals of the same species consecutively. Piélou's equitability index estimates the ratio between observed diversity and maximum possible diversity [2,59].

Finally, to compare the plant species lists from individual interviews and floristic inventories in each village area, Jaccard's similarity index (J; Equation (11)) was calculated [69]. All these analyses were carried out using R (dendrometry package) and Past (version 4.05) software.

$$J={\displaystyle \frac{a}{a+b+c}}$$

(11)

where a is the total number of woody species inventoried in the two habitats being compared; b and c respectively the number of woody species inventoried in one of the two habitats but absent in the other.

3. Results

3.1. Habitats and Species Selection Criteria for Reforestation and Management of Reforested Habitats

3.1.1. Choice of Habitats for Reforestation in Village Areas

Over 70% of respondents reported that reforestation habitats were chosen either through concertation among stakeholders or by village chiefs. Specifically, in Milando village area, the choice of habitats was strongly influenced by the village chief, whereas in Mwawa, it resulted from consultation involving the community, the NGO, the public environmental service, and the village chief (Table 1).

3.1.2. Choice of Woody Species for Reforestation in Village Areas

More than 70% of respondents reported that woody species used for reforestation were selected based on their usefulness and the availability of seeds. In Milando, the availability of seeds was the main factor, while in Mwawa, the choice of woody species was primarily based on the needs of the local community. Other criteria, such as the use of timber and adaptation to soil types, influenced the selection of certain woody species, particularly in Mwawa (14% of respondents; Table 2).

3.1.3. Management Practices on Reforested Habitats Within Village Areas

Around 75% of respondents report that the management of reforested habitats relies mainly on planning and assessment meetings, the installation of firebreaks, and surveillance by forestry brigades. Specifically, the holding of such meetings and the installation of firebreaks are frequently mentioned in both village areas. In addition, plant nursery maintenance was particularly highlighted as a key activity in Mwawa, in contrast to Milando where this maintenance is less reported (Table 3).

3.2. Forest Recovery in Reforested Habitats Compared to Unexploited Miombo in Both Village Areas

3.2.1. Diameter Structure of Individuals Inventoried in Reforested and Unexploited Habitats Within Village Areas

Most individuals inventoried in reforested and unexploited habitats have a diameter at breast height (DBH) of between 10 and 40 cm. In the reforested habitat of Mwawa, many individuals are in the 10-20 cm DBH class, while in Milando, these individuals are distributed across all diametric classes. However, the unexploited habitats in both village areas show a similar diametric distribution, presenting increasingly larger trees compared to the reforested habitats. Furthermore, the "inverted J" diametric structure observed in both habitat types (reforested, unexploited) reflects the predominance of juveniles, indicating active regeneration and the gradual reconstitution of the forest cover, especially in reforested habitats (Figure 2).

3.2.2. Density per Hectare and Ecological Importance of Woody Species Inventoried within Reforested and Unexploited Habitats in Both Village Areas

A total of 442 woody individuals were inventoried in reforested habitats, including 256 in Milando and 186 in Mwawa, belonging to 26 genera (Milando: 17; Mwawa: 21) and 13 families (Milando: 7; Mwawa: 11). In unexploited habitats, 630 individuals were counted: 300 in Milando and 330 in Mwawa, belonging to 37 species (35 per habitat), 27 genera (Milando: 25; Mwawa: 21) and 17 families (Milando: 15; Mwawa: 12). The Fabaceae family dominates in both habitat types, accounting for 60.94% and 74.73% respectively in the reforested habitats of Milando and Mwawa, and 70.67% and 76.97% in the unexploited habitats.

Some wood species cited by respondents as chosen for reforestation, such as Acacia polyacantha, Afzelia quanzensis, and Anisophyllea boehmii, were not recorded in either reforested or unexploited habitats. Nevertheless, of these woody species, Brachystegia spiciformis, Diplorhynchus condylocarpon, and Isoberlinia angolensis are the most represented in reforested habitats, while B. spiciformis remains dominant in unexploited habitats (Table 4).

3.2.3. Dendrometric and floristic parameters of woody individuals inventoried within reforested and unexploited habitats in both village areas

Overall, floristic parameters (number of species, genera, and families per hectare) show no statistically significant differences between reforested and unexploited habitats. However, reforested habitats, particularly in the Mwawa village area, show significantly lower values for density (p < 0.05), mean square diameter, and basal area (p < 0.001; Table 5). These results indicate that miombo is recovering in reforested habitats, although this process remains less advanced than in unexploited habitats.

3.2.4. Floristic Diversity Indices of Reforested and Unexploited Habitats in Both Village Areas

The Simpson and Shannon diversity indices range from 0.0834 to 0.1633 and from 2.503 to 2.809 respectively, with higher values in unexploited habitats. This indicates greater biodiversity in these habitats, where the probability of two randomly selected individuals belonging to the same species is lower. Piélou's equitability, which ranged from 0.7039 to 0.8593, remained almost similar between reforested and unexploited habitats, suggesting a relatively uniform distribution of species in both habitat types (Table 6).

3.3. Similarities Between Ethnobotanical and Floristic Lists of Habitats in Both Village Areas

Jaccard's similarity index varies between 31.58% (between the ethnobotanical list and that of the floristic inventory in the reforested habitat at Mwawa) and 93.75% (between the unexploited habitats). This similarity remains low (below 50%), particularly between the ethnobotanical lists and those of the floristic inventories of reforested habitats in the two village areas. However, the ethnobotanical lists of these two village areas show a similarity of up to 66.67% (Table 7). These observations indicate a high dissimilarity between the ethnobotanical lists and the woody species present in the reforested habitats, while highlighting a high similarity between the floristic lists within unexploited habitats.

4. Discussion

4.1. Involvement of Local Communities in Decision-Making on Reforestation in Both Village Areas

Habitats and woody species for reforestation were selected through concertation, involving local communities, public services, NGOs, and international organizations (Tables 1, 2). These results underline a participatory approach to reforestation, valuing the environmental perception and endogenous knowledge of local communities. This approach to selecting habitats and woody species can be explained by the fact that the NGDOs driving this reforestation process advocate the promotion of a participatory approach, to meet the requirements of funding agencies [34]. This has led to consideration of the environmental perception of local community members when choosing habitats for reforestation. Indeed, in Milando, reforestation targeted habitat degraded by dendro-energy production, while in Mwawa, it was concentrated in post-cultivation fallows, as indicated by the perception maps of Ref. [70]. These habitats were selected because they had been abandoned by local communities after being exploited, respectively for agriculture and charcoal production. In addition, miombo species were chosen for reforestation, to meet the specific needs of local communities (Table 2). Indeed, these species will help maintain the floristic composition, structure, and functions of the forests, thus ensuring the continuity of ecosystem services for the local communities [71]. This contributes to the involvement of local communities in the reforestation process, thereby reinforcing its success [72]. For illustration, other reforestation activities previously conducted in the Lubumbashi region using primarily exotic species, such as Acacia auriculiformis A.Cunn. ex Benth. and Leucaena leucocephala (Lam.) de Wit [73], have not yielded satisfactory results. Indeed, these exotic species have proven to be invasive, threatening local biodiversity [74] and providing ecosystem services that are less comparable to those of miombo woody species [75]. This have led to low community participation and limited sustainability of the reforestation processes. This situation highlights the importance of a participatory approach, which greatly enhances the success of reforestation and its adoption by local communities [36]. Indeed, the active and equitable involvement of the various stakeholders, in particular local communities, ensures that their needs and interests are considered, guaranteeing greater inclusiveness and relevance of the actions carried out. Furthermore, incorporating traditional knowledge enriches restoration strategies, offering adapted and culturally relevant solutions [76]. The results of this study corroborate findings from research conducted in Africa [39,77] and in the miombo ecoregion, particularly in Tanzania [78] and Mozambique [43], highlighting the importance of integrating endogenous cultures and knowledge in the choice of habitats and woody species for reforestation.

However, reforested habitat management practices primarily include planning and assessment meetings, as well as maintenance actions, and surveillance carried out by forestry brigades (Table 3). This can be explained by the fact that, following the implementation of the project to reforest anthropized habitats, local communities are striving to sustain these initiatives despite the interruption in funding. These practices are essential to ensure the sustainability of reforestation and promote the restoration of forest cover. Nevertheless, the implementation of certain activities, such as plant nursery maintenance and the creation of firebreaks, has dwindled, particularly in Mwawa. This is due to a lack of motivation on the part of local communities, attempts to expropriate reforested land, and insufficient post-project monitoring. Sustainable management of reforested habitats requires ongoing action to strengthen ecosystem resilience [76]. Thus, the gradual reduction of these practices exposes reforested habitats to anthropogenic pressures, notably late and repetitive bushfires, which characterize the miombo ecoregion [79-82], and especially the Lubumbashi region [23]. This threat is compounded by intensive tree-cutting for dendro-energy and agriculture, practices that are increasingly observed around reforested habitats. These activities are among the main drivers of deforestation and degradation of miombo [83,84], particularly in the Lubumbashi region [20,22,85]. Weak management and maintenance practices for green spaces, resulting in the exponential degradation of these habitats, have already been reported in Burundi [86]. The results of the present study confirm the findings of previous research conducted in the miombo ecoregion [33,87,88], highlighting the importance of continuity of management practices, such as bushfire control, in the reforestation process. These practices are essential for mitigating anthropogenic pressures and promoting the rapid regeneration of forest cover in reforested habitats.

4.2. Reconstitution of Forest Cover Within Reforested Habitats in Both Village Areas

The results show statistically similar values between reforested and unexploited habitats, for dendrometric parameters, and more particularly for floristic parameters (figure 2; tables 4, 5, and 6). This shows that the miombo forest cover is recovering in reforested habitats, compared with unexploited habitats in the Lubumbashi region. Indeed, the values for diameter structure, density of individuals/ha, root mean square diameter, basal area, and floristic diversity are increasingly like those for unexploited miombo and to the results for unexploited forest found by Ref. [33]. This situation is justified by the reforestation carried out, the protection of these reforested habitats, and the management activities mentioned above, such as the establishment of firebreaks and the monitoring of these habitats, which contribute to the growth and establishment of woody species while being spared from anthropic pressure. These results corroborate those of studies carried out in Mozambique [59,79,89], showing that in the absence of anthropogenic activities, anthropized miombo habitats reconstitute their forest cover over the years up to the pyroclimax stage [11,90]. Nevertheless, this reconstitution is a function of the level of anthropogenic degradation experienced by the habitats and the resilience of woody species to these disturbances [13,59]. This also explains the low values represented by the reforested Mwawa habitat in terms of dendrometric parameters, compared with other habitats. Indeed, the reforested habitat at Mwawa would have undergone a high degree of anthropization, compared with that at Milando, thus explaining this difference in dendrometric parameter values particularly. In addition, the increasingly rare application of management practices works against the biodiversity conservation and reforestation efforts devoted to miombo. The results of the present study corroborate those of other research conducted in the miombo ecoregion [2,13,21,59,91-93], showing that habitat composition and floristic diversity are negatively correlated with anthropogenic disturbance.

4.3. Similarity Between Ethnobotanical and Floristic Lists of Reforested and Unexploited Habitats in Both village Areas

The similarity between the ethnobotanical and floristic lists of reforested habitats remains low (Table 7). Some woody species present on the ethnobotanical lists are absent from the floristic inventory lists, and vice versa. This situation can be explained on the one hand by the fact that, during the floristic inventory, the individuals of certain species chosen for reforestation were still juveniles, with a diameter (DBH) below the pre-counting level set at ≥10 cm for the present study. This lower diameter of these individuals would be justified by the slow growth exhibited by most miombo woody species, as attested by previous studies [2,94], leading to this situation during floristic inventories [95]. Furthermore, the availability of woody species in a reforested habitat depends on these ecological requirements and the technical problems that may arise during the reforestation operation. Indeed, the requirements of a woody species in terms of ecological factors, particularly the physico-chemical properties of the soil, influence its ability to recover, survive, and establish in a habitat [96]. On the other hand, this situation can be explained by the fact that reforested habitats were already teeming with individuals of other woody species, leading to this difference between ethnobotanical and floristic lists.

However, the similarity of floristic inventory lists within reforested and unexploited habitats is low. This situation can be explained by the anthropogenic disturbances experienced by these reforested habitats in the past. Indeed, the composition and floristic diversity of habitat is inversely correlated with anthropogenic disturbance [13,21,92]. These results corroborate previous studies conducted in the Zambezi region [59,92] and particularly in Lubumbashi region [33], showing that the floristic diversity of habitats that have experienced anthropogenic disturbance, remains low, compared to unexploited habitats.

4.4. Implications of Results for Optimized Management of Reforested Habitats in the Lubumbashi Charcoal Production Basin

The miombo forest cover is in full recovery within the reforested habitats of the Lubumbashi charcoal production basin. However, the mechanisms (firebreaks and surveillance) that can regulate human activities are increasingly neglected in these village areas. This leads to a proliferation of human activities around these habitats, affecting efforts to combat deforestation and forest degradation in Lubumbashi Charcoal Production Basin. In response to this issue, environmental education is one of the potential solutions. Indeed, through awareness campaigns, environmental education would increasingly promote the involvement of local communities in the management of these reforested habitats [97]. It would also encourage compliance with regulations governing the protection of these reforested habitats and the continuation of practices regulating anthropogenic activities [98], such as bushfires, charcoal production, and agriculture, the main drivers of deforestation and forest degradation [20,85]. Environmental education has already been used after reforestation projects in Malawi, Lesotho, and Tanzania, to raise local communities' awareness of the need for further action to ensure the sustainable management of these habitats [99]. However, this awareness-raising may not produce the expected results, due to the mistrust and lack of confidence that plague relations between governance players in the Lubumbashi region [27]. The solution to this problem would be to organize dialogue frameworks between the different stakeholders, to renew mutual trust.

Improving land tenure laws and forestry policy is also a key alternative. Strengthened land legislation would secure habitats under local community forest concession (LCFC), which are often coveted by concessionaires, farmers, and dendro-energy producers. Indeed, cases of habitat invasion under biodiversity conservation/preservation status have already been reported in the Charcoal Production Basin of Lubumbashi, resulting in the degradation of the vegetative cover of these habitats [47]. Additionally, reform of forestry policy would help address anthropogenic invasions of these habitats through appropriate sanctions [36,100]. This will only be possible with the support of accredited public services and the advocacy of NGOs and international agencies [101]. However, the strengthening of the existing monitoring framework will have to be considered to ensure continuous monitoring and assess the results of the reforestation activities after the implementation of the related projects.

Finally, mechanisms to encourage local communities to become involved in the sustainable management and expansion of reforested habitats, such as payment for environmental services (PES), is a solution that decision-makers need to implement. Indeed, PES is an incentive mechanism designed to encourage the protection, restoration, or enhancement of natural ecosystems [102]. This concept is based on the idea that beneficiaries of environmental services (governments, and companies) pay local communities for the adoption of practices that maintain or improve forest ecosystems [103]. This type of PES has already been initiated in the miombo ecoregion in Zimbabwe, with convincing results in terms of sustainable management of forest resources [104]. However, this will need to be accompanied by equitable distribution and reasoned use of PES dividends, to prevent conflicts between stakeholders [105].

The present study does not address social risks, such as land conflicts or inequalities in the distribution of benefits between local communities, which could compromise the sustainability of reforested habitats. Such information would enrich the current results and help develop strategies to ensure the long-term sustainability of these habitats.

5. Conclusions

The present study assessed the sustainability of reforestation activities carried out in two anthropized miombo habitats in the village areas of Milando and Mwawa, through individual interviews combined with floristic inventories in two habitat types (reforested and unexploited) for each village area. The results confirm that habitats and woody species for reforestation were selected concertedly, aligning with the environmental perceptions and needs of local communities. Indeed, these habitats were selected in consultation with local communities, public services, NGOs, and international organizations, while the woody species were chosen according to the local communities' needs. This participatory approach ensures the sustainability of reforested habitats, through activities such as planning, maintenance, monitoring, and assessment, involving local communities in the ongoing management of these habitats. The results also confirm that the miombo forest cover is recovering in reforested habitats, with dendrometric and floristic parameter values approaching those of unexploited miombo. Indeed, the averages of dendrometric (diameter structure; density/ha; root mean square diameter; basal area) and floristic (taxa, genera, and families) parameters did not generally show significant differences between reforested and unexploited habitats. Finally, these results confirm that there are similarities and dissimilarities between the ethnobotanical and floristic lists of reforested and unexploited habitats. Certainly, high similarities were found between the floristic lists of these different habitats, while dissimilarities were observed between the ethnobotanic lists and these floristic lists. Although this study does not address social risks, such as land conflicts or inequalities in the distribution of benefits, it nevertheless highlights the importance of including local communities to ensure the sustainable success of reforestation projects. To promote the restoration of forest cover in reforested habitats, decision-makers need to revive environmental education and raise awareness among local communities about the need to adopt practices that support reforestation. Additionally, establishing a payment for environmental services mechanism is necessary to encourage local communities to manage their forests sustainably.