Old Sacred Trees as Memories of the Cultural Landscapes of Southern Benin (West Africa)

Abstract

Large old trees (LOTs) are emblematic elements of the cultural landscape and can live for hundreds of years. They represent an intermediate aspect of cultural heritage, linking spirits and humans. They can also provide a range of ecosystem services. In spite of their importance, declining numbers have been reported. This study examined the diversity of LOTs and the impact of anthropogenic threats on their preservation in three districts of southern Benin: Ketou and Abomey, which represent historical districts with royal courts, and Lokossa, which does not have a tradition as a dynastic seat. Semi-structured interviews focused on ethnobotanical aspects and storytelling were conducted with a total of 150 community leaders and traditional practitioners; these were coupled with an inventory of LOTs to demonstrate their importance in maintaining the heritage and providing ecosystem services in cultural landscapes. Diversity, cultural importance, and ethnobotanical indices were calculated to compare positive and negative attitudes towards LOTs by the local people of the study areas. A total of 270 LOT individuals belonging to 14 species were recorded. The most common species was Adansonia digitata (70 individuals), followed by Milicia excelsa (47 individuals), Ceiba pentandra (37 individuals), and Blighia sapida (25 individuals). Sacred forests and the royal palaces (ten for Abomey and three for Kétou), which are protected by a traditional veto, had the highest number of LOTs (145 individuals) belonging to nine species. Details of 79 specific uses were documented for each plant part of LOTs. The most frequently reported were related to medicinal (80.64%), cultic (16.65%), and craft uses (2.6%). Based on a standard area of 100 km², mean Shannon diversity (H’) and evenness (J) were lower in the cultural landscape of Ketou (H′ = 0.26 ± 0.42; J = 0.23 ± 0.37) compared to Lokossa (H′ = 0.27 ± 0.32; J = 0.21 ± 0.24) and Abomey (H′ = 0.42 ± 0.37; J = 0.35 ± 0.31). The threat patterns suggest that, irrespective of the species involved, certain determining factors (urbanization (35%), the timber trade (18%), and decisions made during the Marxist–Leninist revolution in Benin in 1972 (11%)) have affected and continue to affect LOT abundance and diversity. For better management of LOTs, there is a need to promote decision-making strategies that better align human cultural values and ecological objectives.

1. Introduction

Global change, such as climate variability, changes in land use, and the spread of invasive species, has significant negative impacts on the biological diversity of ecosystems [1]. This loss of biodiversity compromises provisioning, regulation, and cultural ecosystem services on a global scale [2]. Most of these services depend directly or indirectly on plant species; trees in particular also provide habitat for other organisms such as bats [3]. Irrespective of the identity of the species, old, tall trees with thick stems and wide crowns are preferred by many animal and plant species [4]. Large old trees (LOTs) are key ecological structures [5], playing an important role in maintaining essential ecosystem functions [6] and providing habitat for a wide range of native organisms [7]. Different terms have been used to identify them, such as veteran trees, champion or heritage trees [8], ancient trees [9], and large old trees [10]. They are also known as pasture trees [11], residual trees [12], and isolated trees [13]. Although they are generally considered wild rather than domesticated species, they constitute an integral part of the regular diet, culture, and tradition of many indigenous communities [14].

In the context of sustainable plant resource management, LOTs, which frequently represent iconic biota in agro-ecological landscapes, have become an important research topic concerning cultural contributions to biodiversity conservation [15]. They are defined as trees that have been preserved for one or more centuries and are present in human-dominated landscapes [16]. In an African context, these LOTs are considered symbols of the identity of the groups that use them [17]. Despite their well-recognized value, LOTs have declined globally [10]. Threats are generally due to the cumulative effect of several negative anthropogenic factors, including rapid urbanization, intensification of land use [18], erosion of traditional religious beliefs, and the weak power of religious leaders [19]. Recent studies by Patrut et al. [20] have shown that since 2005, nine of the thirteen oldest and five of the six largest African baobabs, including particularly famous ones such as an individual known as ‘Chapman’, have died and collapsed at least in part. In the face of the above-mentioned threats exacerbating the loss of heritage trees, knowledge of their current distribution and abundance is essential to guide their management. To be successful, conservation must include motivations derived from cultural values as well as from science [21]. Conservation efforts may, therefore, be more effective when biodiversity is assessed in relation to traditional knowledge. When beliefs, social customs, and community rights are understood and considered in conservation programs [22], the development of initial ideas for conservation and the implementation of actions for safeguarding species become more participatory. This results in better integration of local communities and leads to a growing interest in maintaining traditional knowledge about the environment [23]. Thus, ethnobotany, which aims to document human-plant interactions, is becoming a central topic in conservation biology [24].

Most studies on LOTs have been carried out in developed countries, whereas the specific conditions in developing countries have been covered less [25]. For example, in Benin, traditional knowledge on LOTs is poorly documented; the few studies that have reported on their current status investigated the impact of the management of ecosystems that are considered sacred on biodiversity conservation [19,26,27]. Earlier studies also demonstrated the negative influence of modern religions and political events that have led to the development of negative attitudes towards LOTs among local people [28,29]. These results highlight the importance of maintaining traditions in order to protect and manage LOTs sustainably. However, the current understanding of cultural contributions to the protection and management of LOTs is still very limited. The planting of trees that eventually developed into LOTs and the long-term preservation of LOTs in Benin is intimately linked to the history of kingdoms (personal observation). LOTs often either exist as roadside trees along the main roads of royal cities or serve to (i) symbolize the foundation of a kingdom, (ii) delimit the royal palace, (iii) symbolize places of worship or graves of defeated enemies, or (iv) commemorate the birth of a child [9]. LOTs in these cases are, therefore, indicators of the management of cultural landscapes by royal dynasties and have always been linked to the evolution of society. In spite of the important knowledge held by the locals on LOTs and their role in the conservation of natural resources, there is a virtual absence of information and scientific data related to their diversity and their unique functional character in the cultural landscape. In Africa, religion and ethnicity are increasingly seen as a cultural component that should not be overlooked, especially when it comes to the conservation of old individuals of valuable species or the safeguarding of the environment in agreement with the local people. In the past, disregard for these aspects that are simple but important for the local people has led to the failure of reforestation strategies.

This study aimed to elucidate the number of LOT individuals and their location in three districts in southern Benin in order to better target management strategies to reverse negative impacts on them. In addition, the study was designed to maintain and strengthen existing ethnobotanical knowledge about LOTs. The study aimed in particular to (1) assess the diversity of LOT species, (2) explore the role of religious aspects in the current distribution of LOTs in local cultural systems, and (3) assess the threats to LOTs in each district. To achieve these objectives, the following hypotheses were proposed: (i) Cultural landscapes with a history of a royal dynasty have a higher diversity of LOT species than landscapes without such a history; (ii) Based on the observation that cultic rites are performed in remote and hidden areas, we argue that LOT species exhibit a centrifugal distribution as they are favored for cultic rites; (iii) Traditional knowledge about LOTs is evenly distributed at the gender level; and (iv) Decline factors of LOTs are related to the erosion of traditional beliefs.

2. Materials and Methods

2.1. Study Area and Sites

The study was conducted in southern Benin, located between latitudes 6°25′ N and 7°30′ N and longitudes 1°35′ E and 2°49′ E. The climate is sub-equatorial with two rainy seasons from April to mid-July and from mid-September to October (average annual rainfall of 1200 mm), alternating with two dry seasons from November to March and from mid-July to mid-September. This part of the country (from the coast to about 7°30′ N) comprises savannahs, grasslands, farmlands, and fallows, mixed with small patches of semi-deciduous and swampy forests [30]. More specifically, data were collected in three cultural landscapes. The first two, located in the departments of Zou (Abomey) and Plateau (Ketou), have a historical dynastical tradition and are distinguished by the strong presence of LOTs maintained over generations. The district in the department of Mono (Lokossa), which has not known a historical dynasty as such, was used as a control area, with the aim of elucidating practical reasons for the preservation of trees over millennia apart from royal myths or dogmas (Figure 1). The district of Abomey covers an area of 142.1 km² with 90,195 inhabitants, and the district of Ketou covers an area of 1792.6 km² and has 157,352 inhabitants. The city of Lokossa covers an area of 300 km² with 104,961 inhabitants [31].

These areas are distinguished from each other by the presence of different sociolinguistic groups. The study area covers the Aja-Tado sociolinguistic area, which is mainly composed of Fon in Abomey, Yoruba and related groups in Ketou, and Adja in Lokossa. Economic activities include agriculture, livestock breeding, fishing, hunting, and crafts. The dominant religions are animist (63.3%), Christian (21.2%), and Muslim (15.6%) [31].

2.2. Coordination with the Administration and Obtaining Consent of Interview Partners

Data collection began with a presentation of the objectives of the study to the regional authorities and knowledge holders through a letter requesting permission to conduct the study. The letter was addressed to the political and administrative authorities of each district (Mayor, Head of District, or Head of Neighborhood/Village) and to actors in the agricultural and forestry sectors (Heads of the forestry sector in the area and the Head of the Regional Centre for Agricultural Promotion). Personal requests were addressed to the chiefs of the royal communities and the representatives of the herbalist (a professional who sells medicinal plants and preparations from medicinal plants and natural ingredients used as medicines) as they are most active in the management and maintenance of old tree individuals. All interviewees gave their full agreement prior to their inclusion in the study, while remaining anonymous.

2.3. Sampling Design and Data Collection

Data were collected through interviews and field studies. For the interviews (historical and ethnobotanical), a semi-structured approach was used. To obtain information about the maintenance and utilization of old tree individuals over a time period of several decades, interviewees over 60 years of age with detailed knowledge of the study area were included in a preliminary survey (October 2019) that was conducted before the main study (November to December 2019). The participants were mostly community leaders, traditional leaders, and traditional practitioners. They were asked whether they were aware of the existence of LOT individuals, including both extant ones and ones that had disappeared, and they were asked about the way in which the trees are used. The preliminary survey was conducted with 50 people selected from the study areas through purposive sampling (snowball method).

The proportion Fn (%) of those with knowledge of the LOTs in the preliminary study was estimated at 84%. The sample size of respondents, calculated using the formula from Dagnelie [32] (Equation (1)) as 148.5, was rounded to 150.

$$n={\mu }_{1-\alpha /2}^2\frac{Fn\left(1-Fn\right)}{{\delta }^2}$$

(1)

In Equation (1), n is the total number of individuals surveyed in the three districts combined, μ_1−α/2 represents the random normal variable for an error probability of first order α = 5%, μ_1−α/2 = 1.96, Fn = 42/50 = 0.84 is the proportion of individuals with knowledge of or using an LOT, and δ is taken as the marginal error, set at 0.08. The respondents were classified based on sociolinguistic groups. Their characteristics are summarized in

Table 1. Profile of the respondents according to districts.

Cultural Landscape	Variables	Categories	Number of Individuals	Relative Frequency (%)
Abomey	Gender	Women	17	34
		Men	33	66
	Age	60 ≤ i ≤ 80	45	90
		More than 80 years	05	10
	Ethnicity	Fon	50	100
	Religion	Christian	10	20
		Animists	40	80
	Social and economic category	Farmer	14	28
		Craftsman	13	27
		Commercial	7	14
		Community leader	8	15
		Traditional therapist	8	16
Ketou	Gender	Women	6	12
		Men	44	88
	Age	60 ≤ i ≤ 80	48	96
		More than 80 years	2	4
	Ethnicity	Ilè-ifè	3	6
		Mahi	26	52
		Nago	21	42
	Social and economic category	Farmers	30	60
		Craftsman	9	18
		Commercial	3	6
		Community leaders	4	8
		Traditional therapist	4	8
	Religion	Christian	25	50
		Animists	24	48
		Muslim	1	2
Lokossa	Gender	Women	6	12
		Men	44	88
	Age	60 ≤ i ≤ 80	42	84
		More than 80 years	8	16
	Ethnicity	Adja	17	34
		Kotafon	33	66
	Social and economic category	Farmers	12	24
		Craftsman	12	24
		Community leaders	16	32
		Traditional therapist	10	20
	Religion	Christian	11	22
		Animists	39	78

. The majority of respondents were male (74%). The Fon sociolinguistic group was the most frequently surveyed, representing 30% of the sample.

The interviews focused on:

–

The local names of the LOTs and their meanings;

–

The factors that favored the conservation or threatened the existence of LOTs in terms of cultural, political, and natural events that occurred in the district;

–

Ethnobotanical uses (food, medicinal, handicraft, and cultural);

–

The dynamics of LOT populations in terms of increases or decreases in the number of tree individuals.

To obtain additional information about the LOT individuals, field studies along line transects of 2 km in length were carried out at all sites where LOTs had been reported to exist by the interviewees. The transect approach allowed us to record the locations of LOT individuals and to measure the distances between trees as well as to note types of tree habitats. Furthermore, this approach enabled us to search for possible other LOTs that might not have been mentioned by the local experts during the interviews. All LOTs were geolocated, and the location type (royal palaces, princely courts, collective family space, and natural sites, i.e., gazetted forests and sacred forests protected by a traditional veto) was recorded. To provide further detail on land use, land use maps based on SPOT-5 images taken in 2018 were prepared for each study district. This fieldwork was carried out with the help of a local guide familiar with the study area. The following data were collected on each LOT: species, geographical coordinates, diameter at 1.30 m from the ground, total height as measured with a Suunto Clinometer, signs of sacredness and/or protection of the tree, signs of vandalism, and access path. Herbarium specimens were prepared for LOT individuals not identified in the field; the specimens were taken to the National Herbarium for identification. The conservation status was taken from the IUCN red list (https://www.iucnredlist.org/search (accessed on 15 January 2019)).

2.4. Data Analysis

Data from the field study were used to produce a table on the floristic diversity of LOTs. The dominance of each species was calculated as the proportion made up by the individuals of this species as a percentage of the total in the spatial unit. In addition, the average age of trees belonging to the same species was calculated. For each spatial unit, characteristics of the community of large old trees were calculated as species diversity (H) and evenness (J).

Species diversity was represented by the Shannon–Wiener index (H) calculated by:

$$H=-\sum pi\left(lnpi\right)$$

(2)

In Equation (2), pi is the proportion of individuals of i-th species.

Diversity is low when H′ is less than 3, medium when H is between 3 and 4, and high when H is greater than or equal to 4 [33].

Evenness index (J) was calculated by:

$$\mathrm{J}=\frac{H}{lnS}$$

(3)

In Equation (3), H is the Shannon–Wiener index and S is the total number of species [33]. J varies from 0 to 0.6 (one species has a very high abundance), from 0.6 to 0.7 (medium equitability), and from 0.8 to 1 (all species are equally important) [33].

In order to make a comparison between the districts, after calculating the diversity indices according to the actual area of each district, an extrapolation was made, and the Shannon–Wiener diversity and evenness were calculated again for an area of 100 km² [34] using the Biodiversity R package [35]. The geographic coordinates of LOT individuals were used to establish the species richness at the locality level of each landscape. The GPS was set to WGS 1984 UTM 31N and degree-minute-second modes. Two types of GPS records were used: waypoints, which are marked positions, and tracking data, which are continuous records. Waypoints are marked on the maps by different colored symbols representing different species, and tracks are the continuous lines connecting the symbols to each other. The GPS data collected in the field were downloaded using Garmin DNR software. These data were then processed using a Geographic Information System (ArcGIS 10 software). The data were organized according to point, linear, and polygonal features. In an exploratory analysis, the number of LOTs and the number of LOT species were investigated in relation to the site of occurrence, age, and health status in each district. The criteria used to assess the health status of the trees were as follows: low (pronounced signs of vandalism such as heavily debarked stems, enlarged branches, an undeveloped crown, and the presence of several cavities), medium (average signs of vandalism, an acceptable crown development, and few cavities), and good (no evidence of vandalism, straight stems, no bark damage, a well-developed crown, and no cavities).

Publications [36,37], respectively, were used to assign the life forms to each LOT species and to obtain information about their geographic distribution.

Data from the interviews allowed us to calculate two indices to explore traditional and cultural knowledge of LOTs:

The Use Value (UV) index as defined by [38] and modified by [39] was used.

$$\mathrm{UV}=\sum U/n$$

(4)

where UV = use value of the species.

U = number of citations per species;

n = number of respondents.

The Cultural Importance Index (CI) by use category in cultural landscapes was estimated. It represents the value of the cultural importance from the perspective of individual informants and the community, as defined in [40]. Therefore, the value of the cultural importance from the perspective of individual informants was calculated according to Equation (3):

$$CI={{\displaystyle \sum }}_{U=u1}^{unc}\sum {\displaystyle \sum }_{I=URi}^{IN}URui/N$$

(5)

URui = the total number of informants reporting a species within a particular use category, NC = the total number of use categories, and N = the total number of informants.

Differences between the Cultural Importance Index (CI) values in each district by use category were analyzed using a Kruskal–Wallis test (as the conditions of normality and homogeneity of variances were not met). Radar plots were used to depict the most cited uses for LOTs by district and gender.

Furthermore, on a combination of socio-demographic variables (sociolinguistic group, gender, and age class) according to the districts, a principal component analysis was carried out on the cross-tabulation of the frequency of quotation data in order to assess a possible preference for LOTs among certain sociolinguistic groups.

2.5. Definitions of Terms

2.5.1. Biological Terms

Large old tree: There are defined as trees estimated to be over 100 years of age and distributed in human-dominated landscapes. Age determination based on tree ring sampling was not possible due to the protected status of trees. Thus, age estimates are based mainly on historical records and interviews with local elders. This method was recently used as a relatively effective method for determining the age of large old trees [16].

2.5.2. Social Terms

Positive attitude towards LOTs: In the context of this study, a positive attitude towards LOTs is a positive perception developed through the recognition by the local peoples of the psychic, ecological, aesthetic, and spiritual benefits brought by the large old native tree species.

Negative attitude towards LOTs: In the context of this study, a negative attitude towards LOTs is defined as the development of a negative perception of large old native tree species that can lead to the abandonment of preservation acts or even to their elimination.

Voodoo: Benin is a West African country well known for its traditional religion known as Voodoo. Followers of Voodoo recognize a supreme creator and believe in spiritual entities who act as intermediaries between human beings and the “highest god” [41].

Preservation act: Any action taken or any decision made by local people to contribute to the maintenance of individuals of LOTs in cultural landscapes.

2.5.3. Terms Used to Describe the Social Context of the Sites of Large Old Trees

Collective family space: This refers to the so-called traditional squares (ranging from 200 to 450 m² or more depending on the social level of the community) that play a fundamental role for local family communities (the family community includes the extended family living around the square, but also family members living in other cities or abroad). They are important places in terms of religious practices, as well as places of sociability, conviviality, family proximity, and neighborhood, from which various cultural, social, and commercial uses develop.

Royal palace/Princely court: The royal palaces are sites of collective customary law. Bequeathed to the princes of the royal families, these palaces are made up of sites and spaces that contain many different elements of cultural and social significance, including LOTs, and command the respect of a large part of the human population. They are a group of buildings and open spaces that are in some cases delimited by enclosing walls that are 8 to 10 m in height and varying from one king to another. Royal families have a positive influence on the maintenance of LOTs because each family keeps, either in its royal court or in the front of the house, an individual LOT that represents the family’s history. In total, in the study, there are 14 royal families in Abomey (where the royal system has existed since 1620) and 5 in Ketou (where the royal system has existed since 1400). The current form of governance still recognizes in its policies the unique place of the royal dynasty of each of the cities studied.

Sacred forest: Here, sacred forests are defined as ecosystems with a small area (ranging from 0.5 to 1.5 ha) that is maintained by local people. Sacred forests often remain in areas where forests have declined because they contain old trees (ranging from 4 to 7 individuals) of great religious importance for a particular group, linked to a particular culture or tradition.

Gazetted forest: Gazetted forests are managed based on a national decree. The term refers to any part of the natural forest that has been withdrawn from the pressure of land clearing. The ecosystem is managed for species conservation, species enrichment, and soil regeneration.

3. Results

3.1. Taxonomy, Life Forms, and Biogeographic Types of LOTs

A total of 270 LOT individuals were recorded. These belonged to 14 species, 14 genera, and 8 families. The families of Malvaceae, Moraceae, and Sterculiaceae were the most frequent with 118, 68, and 27 LOT individuals, respectively. The LOTs of the study area were split into two biological types belonging to the group of plant life forms known as phanerophytes: megaphanerophytes and mesophanerophytes. The mesophanerophytes (mPh, indicating a tree from 8 to 32 m in height) represented 65% of the LOTs inventoried compared to 35% for the megaphanerophytes (MPh, indicating a tree over 32 m in height). The largest group among the LOT species inventoried were taxa from the Afro-tropical region (28.57%). The remaining species were from the Sudano-Guinean (21.43%), paleotropical (21.43%), Guinea-Congolese region (14.28%), Pantropical (2.04%)and Afro-malgache regions (2.04%).

The number of tree individuals was not evenly distributed across species, and the species were not evenly distributed across districts or types of sites. The dominance pattern observed in the historical districts of Abomey and Ketou is characterized by the presence of species such as Adansonia digitata (70 individuals, 25% of the total), followed by Milicia excelsa (47 individuals, 17%), Ceiba pentandra (37 individuals, 13%), and to a lesser extent Blighia sapida (25 individuals, 9%). B. sapida was present with significantly higher frequency at the front of royal palaces. Collective family spaces (some of which were represented by large areas including crop and old fallow land) were characterized by the presence of LOT species such as A. digitata, M. excelsa, A. africana, and B. aethiopum, and to a lesser extent by I. gabonensis and F. umbellata. Species such as T. scleroxylon, C. pentandra, and A. toxicaria were more common in natural sites, specifically in sacred forests (

Table 2. Botanical information, species composition, and presence of LOTs in their site of occurrence.

Species	Family	Life Form	Chorology	Tree Count	Tree Count (%)	c P d	d P L
Ficus umbellata Vahl	Moraceae	mPh	SG	1	1	1	1
Lecaniodiscus cupanioïdes Planch.	Sapindaceae	mPh	Pal	2	1	1	1
Irvingia gabonensis Baill	Irvingiaceae	MPh	AT	3	1	2	1
Parkia biglobosa (Jacq.) R. Br.	Fabaceae	mPh	SG	5	2	2	1
Afzelia africana Smith ex Pers.	Fabaceae	mPh	AT	6	2	2	2
Cola gigantea A. Chev.	Sterculiaceae	mPh	SG	10	4	3	2
Rhodognaphalon brevicuspe Sprague	Malvaceae	MPh	GC	11	4	1	1
Borassus aethiopum Mart.	Arecaceae	mPh	AT	15	6	3	2
Triplochiton scleroxylon K. Schum.	Sterculiaceae	MPh	GC	18	7	2	1
Antiaris toxicaria Engl.	Moraceae	MPh	Pal	20	7	3	2
Blighia sapida K. D. Koenig	Sapindaceae	mPh	Pal	25	9	3	3
Ceiba pentandra L. Gaertn.	Malvaceae	MPh	Pan	37	14	3	2
Milicia excelsa (Welw.) C. C. Berg	Moraceae	MPh	AT	47	17	3	3
Adansonia digitata L.	Malvaceae	mPh	AM	70	25	3	4

Legend: ^c P _d denotes the number of cities present; ^d P _L denotes the number of the occurrence site; MPh: megaphanerophytes; and mPh: mesophanerophytes. AM: Afro Malgache; Pal: Paleotropical; SG: Sudano-Guinean; AT: Afro-tropical; GC: Guinea-Congolese; and Pan: Pantropical.

). The dimensions and estimated ages are displayed in

Table 3. Dimensions and estimated age of LOTs (estimation has been made according to the reign of kings).

LOT Species	Diameter (cm)		Height (m)		bAge m (Years)
	Min	Max	Min	Max
Adansonia digitata	57	373	5.22	30.55	133.23 ± 48.17
Milicia excelsa	100	262	16.33	36.98	132.13 ± 47.28
Ceiba pentandra	101	248	16.64	62.62	132.90 ± 46.99
Parkia biglobosa	91	91	12.88	12.88	123.18 ± 33.77
Blighia sapida	87	192	8.7	29.82	130.82 ± 46.43
Antiaris toxicaria	32	229	21.45	48.14	120.84 ± 31.82
Triplochiton scleroxylon	91	231	15.04	62.4	122.60 ± 20.39
Cola gigantea	106	283	15.04	21.96	122.74 ± 33.69
Ficus umbellata	56	126	13.92	13.92	190
Lecaniodiscus cupanioïdes	195	201	25.46	34.44	141.66 ± 20.41
Irvingia gabonensis	278	380	12.23	15.30	119.74 ± 44.64
Afzelia africana	92	132	11.85	17.11	121.29 ± 32.82
Rhodhognaphalon brevicuspe	56	126	13.86	26.65	117.21 ± 18.52

Legend: ^bAge _m: denotes mean tree age ± standard deviation.

.

3.2. Diversity of LOT Species

Diversity index values were low compared to the standard value [33] in both historical and non-historical districts (

Table 4. Diversity indices and observation in terms of the number of LOTs by district based on the area of the district (top panel). Diversity indices and observation in terms of the number of LOTs by district based on a unit area of 100 km² (bottom panel).

District	Area (km2)	Density of Human Population (hbts/km2)	Nb. Observ. (Trees)	Species Richness	Species Richness (Mean ± SD)	Shannon’s Index	Pielou Evenness
Abomey	142.1	641.3	93	11	4.5 ± 3.5	0.74	0.62
Ketou	1792.6	87.8	109	12	3.5 ± 2	0.75	0.66
Lokossa	300.3	349.52	68	10	3.5 ± 2.5	0.62	0.49
District	Total Species Richness/100 km2	Nb Observ./100 km2	Shannon’s Index/100 km2	Shannon’s Index (Mean ± SD)	Pielou Evenness/100 km2		Pielou Evenness (Mean ± SD)
Abomey	8.44	65.44	0.52	0.42 ± 0.37	0.43		0.35 ± 0.31
Ketou	1	6.10	0.04	0.26 ± 0.42	0.03		0.23 ± 0.37
Lokossa	3.33	22.65	0.20	0.27 ± 0.32	0.16		0.21 ± 0.24

). The comparison of the number of LOT individuals per district was based on a unit area of 1 km² (Table 4).

The district of Abomey had a large number of individuals with 0.65 trees/km². It was followed by the district of Lokossa (0.22 trees/km²) and the district of Ketou (0.06 trees/km²) (Table 4). Most tree individuals were located at the storefronts of the collective family spaces, forests protected by a traditional veto, and to a lesser extent in front of royal palaces (Figure 2).

Concerning the health status of LOTs as classified by the morphological appearance (the development of the stem and crown and the appearance of the bark), about 64.81% of the LOTs had “good” sanitary status; these were mostly found in the gazetted forests (Figure 3). The health status of the trees was worse at the storefronts of collective family spaces and royal palaces.

More than half of the LOTs fell within the range of 100 to 120 years (Figure 4). The age of the trees was closely linked to the history of the kingdoms; the oldest trees (approximately 400 years old) were inventoried in the oldest kingdom (the cultural landscape of Ketou). The district of Abomey was represented by trees that were at most 300 years old and characterized by Blighia sapida. The youngest trees (100 < year < 200) were inventoried in the cultural landscape of Lokossa (Figure 4).

A comparison of species richness at the scale of the different localities within the study sites showed that LOTs were centrifugally distributed within the district (Figure 5a–c). Several LOT individuals were found in crop, old fallow land, and sacred forest. However, LOT species have relatively significant diversity in the urban area of the district linked to the royal palaces, especially in Abomey (6.25 ± 1.75 species), and to the collective family spaces built in the urban area in Lokossa (4.5 ± 3.5 species) (Figure 6a–c).

3.3. Traditional Knowledge of LOTs

3.3.1. Local Taxonomy and Basis

The local names were diverse and varied not only according to the LOTs, but also from one district to another and even within the same sociolinguistic zone. In total, 31 vernacular names were recorded for the 14 LOT species inventoried (

Table 5. Meaning of the vernacular names of the inventoried LOTs.

LOT Species	Vernacular Names	Meanings	Used Parts	Uses Category	Status/IUCN	Status Benin
Adansonia digitata	Kpassa a, azizon b Lagba c, Otché oriri d	Tree embodying strength and wealth a Tree that restores energy b Tree of abundance d	Leaf, root, bark, fruit	Food, med, cult, handicraft	LC	LC
Milicia excelsa	Loko a,b,c,e, Iroko d	Majestic tree a,b,c,e Sacred tree d	Bark, fruit, stem (Lumber product)	Med, cult, handicraft	VU	EN
Ceiba pentandra	Gueédéhountin a,b,e, Houtchin c, Aagou d,f	Tree of Guede divinity a,b,c Thorn tree d f	Stem (lumber product)	Med, cult, handicraft	LC	LC
Irvingia gabonensis	Assrotin a	-	Fruit	Food, med, cult, handicraft	NT	NT
Blighia sapida	Lissètin a, Agnissètin b,c, Esinsin e, Ishin d,f	Tree with red and sweet fruit a Tree of peace for the kingdom e Tree that bears fruit by opening d,f Tree of the Oro fetish ritual d,f Tree embodying the Gu divinity a,b,c	Fruit	Food, cult	LC	LC
Antiaris toxicaria	Guhotin a,b,e, Gbéhortin c, Ooro d,f	Tree used for ritual of the Oro fetish d,f Tree embodying the Gu divinity a,b,c	Stem (lumber and energy)	Cult, handicraft	LC	NT
Ficus umbellata.	Vunvuntin a,b, Odan d	Tree with large shade a Palaver tree for meetings d	-	Cult	LC	LC
Parkia biglobosa	Ahwatin a,b, Ayi d	-	Bark, fruit	Food, cult, handicraft	LC	LC
Rhodognanphalon brevicuspe	Kpatin-dehuntin a, Huntchin b,c	Tree to delimit fences	Bark, stem (lumber and energy)	Cult, handicraft	VU	LC
Triplochiton scleroxylon	Ewetin e, Arere d	Sacred tree e Tree of Oro ritual d	Bark, stem (lumber and energy)	Cult, handicraft	LC	EN
Lecaniodiscus cupanioides	Ganhotin a,b, Ganhotchin c	-	Bark, lumber	Cult, handicraft	LC	LC
Afzelia africana.	Kpakpatin a, Aïran d	-	Bark, stem (lumber)	Cult, handicraft	VU	EN
Cola gigantea	Golotin a	Tree of protection a	Fruit	Food	LC	LC
Borassus aethiopum	Gbégontin a	-	Fruit, leaf	Food, handicraft, med	LC	VU

Legend: LOT: Large old tree; Ethnicity: ^a (Abomey): Fon, ^b,c (Lokossa) respectively: Kotafon and Adja, ^d,e,f (Ketou) respectively: Nago, Mahi, and Ilè-ifè; Status: Endangered (EN), Vulnerable (VU), Near Threatened (NT), and Least Concern (LC).

). Each LOT species had an average of two local names. The variability of local names was greatest in Ketou (50% of total names), followed by Lokossa (33%), and finally Abomey (16%). Different criteria were used as the basis for naming a species locally. The most important criteria referred to the morphology of the tree (40%), the habitat (27%), the divinity embodied by the tree (20%), and the taste of an organ consumed from the tree (13%). Figure 7 summarizes, as a word cloud, functions and criteria explaining the basis of the local names most reported by people when asked to name LOTs.

3.3.2. Use of LOTs

The calculation of use values for large old trees showed that four LOTs were the most cited for a total of 79 specific uses of plant parts (

Table 6. Use value of LOTs.

Species	Use Value		Reported Use by Organ
	∑ UR	UV	∑ UR	UV
Cola gigantea	2	0.01	2	0.01
Ficus umbellata	2	0.01	2	0.01
Lecaniodiscus cupanioïdes	2	0.01	2	0.01
Triplochiton scleroxylon	3	0.02	3	0.02
Parkia biglobosa	4	0.03	2	0.01
Rhodognaphalon brevicuspe	5	0.03	3	0.02
Irvingia gabonensis	6	0.04	5	0.03
Afzelia africana	11	0.07	4	0.03
Antiaris toxicaria	11	0.07	8	0.05
Blighia sapida	18	0.12	10	0.07
Ceiba pentandra	27	0.18	6	0.04
Milicia excelsa	72	0.48	7	0.05
Adansonia digitata	103	0.69	10	0.07

Legends: UR: Reported Use; UV: Use Value.

and Supplementary Materials). These are Adansonia digitata (UV = 0.69), Milicia excelsa (UV = 0.48), Ceiba pentandra (UV = 0.18), and Blighia sapida (UV = 0.12). Among the use categories, the medicinal category was the most important, involving 32% of the LOTs (

Table 7. The most frequently mentioned specific uses for some species.

LOTs	PU	Associated Cultural Practices/Medicinal Uses	FRC (%)
Ceiba pentandra	Thorn	Search for 16 thorns and keep them with you to protect you from evil spirits.	0.66
	Leaf	Drink a glass of the decoction to reduce a high fever.	1.33
Milicia excelsa	Leaf	Drink the decoction to treat the spleen.	1.33
	Sap	Put on the head of babies to close a fontanelle.	1.33
	Stem	For the collection of sacrifices.	2
Blighia sapida	Fruit	Dry, crush, and use as soap.	2.16
Triplochiton scleroxylon	Stem	Wrapped in a white cloth, is used to prepare for the release of the deity Oro.	2.66
	Root	Drink half a glass a day of the decoction for the improvement of visual acuity.	4.66
Adansonia digitata	Leaf	Triturate + honey, macerate for 7 days, and drink a glass (3 times a day): Strengthens male fertility.	7.33
	Root	To be combined with other species to fight against evil spirits.	11..33
	Bark	Drink a glass (twice a day) of the infusion for the treatment of malaria.	53.33

Legend: PU: Parts used; FRC: Relative frequency of quotation of LOT for the specific use mentioned by the respondents.

). It was followed by the food (28%), cultural (20%), and handicraft (16%) categories. The LOT species most involved in the treatment of diseases and symptoms were Adansonia digitata (20% of medicinal recipes) and Milicia excelsa (13%). All plant organs were involved in the constitution of the recipes. Leaves were the most used organ with a citation rate of 33%. They were followed by fruits (22%), bark (22%), and roots (11%).

3.3.3. Cultural Importance of LOTs

People’s cultural knowledge of traditional uses of LOTs differed significantly between districts (p < 0.001). Local people were more knowledgeable about the traditional uses of LOTs in the city of Lokossa (CI = 0.37) than in the two royal cities (Abomey CI = 0.32; Ketou CI = 0.30). In addition, when the data were analyzed according to gender, we found that men gave greater importance to LOTs than women (Figure 8).

The significance of the LOTs, based on the frequency of citations by the association of ethnicity, gender, and age class and subjected to PCA, indicates that 66.2% of the initial ethnobotanical information is explained by the first three axes, which is sufficient to ensure accuracy of interpretation. The correlation coefficients between each of the three axes and the LOTs are presented in Table 8. The analysis of this table shows that:

–

Axis 1 is the axis of use of A. toxicaria, M. excelsa, P. biglobosa, B. aethiopum, B. sapida, C. pentandra, L. cupanioides, A. digitata, A. africana, and R. brevicuspe (correlation coefficients > 0.5). It is formed mainly by species planted around royal palaces and princely courts, and used to delimit concessions and endogenous temple sites. On this axis, we note that good knowledge and use of A. toxicaria and M. excelsa is often associated with knowledge and use of B. sapida, C. pentandra, A. digitata, and R. brevicuspe;

–

Axis 2 is the axis of use of T. scleroxylon. This axis is formed by the use of T. scleroxylon, which is a sacred species;

–

Axis 3 is the use of F. umbellata, C. gigantea, and I. gabonensis. This axis is formed by species used for shade and for food.

Table 8. Correlation coefficients between principal components and LOTs (PCA).

LOT Species	Axis 1	Axis 2	Axis3
Adansonia digitata	0.64	0.62	0.04
Afzelia africana	0.62	0.43	−0.26
Antiaris toxicaria	0.92	0.11	0.07
Blighia sapida	0.81	0.21	0.30
Borassus aethiopum	0.82	−0.54	0.07
Ceiba pentandra	0.77	0.40	0.01
Cola gigantea	−0.09	0.15	0.78
Ficus umbellata	−0.02	0.20	0.90
Irvingia gabonensis	−0.00	0.15	0.45
Lecaniodiscus cupanoides	0.72	−0.59	−0.02
Milicia exelsca	0.90	0.26	0.06
Parkia biglobosa	0.89	−0.25	−0.06
Rhodognaphalon brevicuspe	0.56	−0.08	−0.15
Triplochiton scléroxylon	0.31	0.70	−0.40

Table 8. Correlation coefficients between principal components and LOTs (PCA).

LOT Species	Axis 1	Axis 2	Axis3
Adansonia digitata	0.64	0.62	0.04
Afzelia africana	0.62	0.43	−0.26
Antiaris toxicaria	0.92	0.11	0.07
Blighia sapida	0.81	0.21	0.30
Borassus aethiopum	0.82	−0.54	0.07
Ceiba pentandra	0.77	0.40	0.01
Cola gigantea	−0.09	0.15	0.78
Ficus umbellata	−0.02	0.20	0.90
Irvingia gabonensis	−0.00	0.15	0.45
Lecaniodiscus cupanoides	0.72	−0.59	−0.02
Milicia exelsca	0.90	0.26	0.06
Parkia biglobosa	0.89	−0.25	−0.06
Rhodognaphalon brevicuspe	0.56	−0.08	−0.15
Triplochiton scléroxylon	0.31	0.70	−0.40

The projection of the different LOTs into the axis systems shows that Mahi, Nago, Kotafon, Adja, and Fon men over 60 years old have a very good knowledge of A. digitata and B. sapida as cultural memory, specifically their role bordering the royal palaces. They use the species A. toxicaria, M. excelsa, P. biglobosa, and C. pentandra as species delimiting either places of worship or family concessions. The other species forming this first axis are recognized for the food, therapeutic, and craft benefits they provide. On the other hand, Fon men over 80 and Fon women over 60 years old know T. scleroxylon as a species used in endogenous ceremonies. They recognize and use it for crafts and energy (Figure 9).

In addition, the species C. gigantea and I. gabonensis are well known and used by Fon women and men over 60 and by Nago women for food and trade.

LOTs are used more for cultural purposes (rituals) in the city of Lokossa and more for handicrafts by men in the city of Abomey. In Ketou, they are more valued for food. The cultural values attached to conserving LOTs that were most cited in historical discussions with local communities and community leaders were summarized in

Table 9. Description of the cultural values (local conservation method) leading to sacralization of some LOTs.

Species	Cultural Values and Associated Totems	Utilities
Adansonia digitata	Shelter of the cult of the divinity “Tôhwiyô” Tree marked by the presence of fetish temple	– Place of presentation and cultural baptism of newborns – Place of cultural ceremony to ward off bad spells and setbacks related to adultery
Antiaris toxicaria	Sacred tree for the followers of the deity “Toxôsù” The tree is surrounded by a white cloth	– Place of rituals to wash away the curse of mentally disabled and their parents – Place of ceremonies for requests and thanks by the followers to the deity
Ceiba pentandra	Sacred tree for the followers of the deity “Dan” Tree marked by the presence of an altar for the divinity	Place of ritual to ask the deity for protection, prosperity, and wealth
Milicia excelsa	Sacred tree for the followers of the Oro cult Tree with specific markings and present in or near the convents

and Figure 10A,B.

3.3.4. Population Dynamic of LOTs and Decline Factors of the Species

Despite the fact that LOTs were mainly protected by traditional and cultural principles, there are still threats to their conservation. Among the risk factors within the cultural landscape, growth of the human population constitutes the main factor for the three studied areas (Figure 11). The secondary risk factor is certain political decisions made during the 1972–1976 revolutionary period in Abomey (the felling and burning of individual old trees which were very often considered to be witchcraft shelters) (Figure 12A). Other factors include urbanization and road development in Ketou and the trade in timber, wood products, and charcoal in Lokossa. Other recurrent threats are the debarking of LOTs (Figure 12C) for medicinal and other purposes and the emergence of new religions that have led to the disappearance of the traditional values/principles that governed the protection and conservation of these species.

Overall, 80% of the respondents indicated their perception of a decline in the number of LOTs in their environment. A highly significant difference (p < 0.001) was observed in perceptions between the landscapes studied. Stability was mentioned more often by respondents (10%) from the city of Lokossa than by those from other districts.

4. Discussion

4.1. Species Diversity, Traditional Knowledge, and Decline Factors of LOTs

Plant species are the main resource used by communities (traditional and modern) for various purposes (spiritual, dietary, therapeutic, fodder, boundary marking, etc.). They occupy a central place in the endogenous rituals of worship [42,43] and were once adopted as species of great cultural value by our forefathers; knowledge about them has been passed on from generation to generation in the form of emic knowledge, which now forms the basis of regional systems of LOT use. Thus, each area has a pattern of use of natural resources that is rooted in its culture. However, compared to the number of LOT species reported by previous studies from other regions (63 species on 273 km² in Macau, southwest of Hong Kong [44], 232 species in China [45], and 80 species on 2700 km² in Wuchuan, Southwest in China [16]), the number of LOT species (14) recorded across the three landscapes studied seems to be low. This low diversity could be due to the size of the study districts, even though some areas (e.g., Lokossa = 300 km²) appear to be larger than those in the studies mentioned above (e.g., Macau = 273 km²). On the other hand, the types of sites surveyed differ significantly in terms of urban environments. The studies in [44] considered national urban parks, public parks and gardens, temples, churches, and cemeteries. All these places may have a different history of interventions than the sites in the districts of Abomey, Ketou, and Lokossa, particularly with regard to tree planting and maintenance. Moreover, the relatively low number of species inventoried in this study could also be linked to the type of species studied (native species only), as compared to the studies mentioned above (native and exotic species). Indeed, the characteristics and distribution of heritage trees vary notably by geographic region, management measures, and urban development patterns [44]. For example, Beijing has identified 39,408 heritage trees, and most of them have been preserved in historical sites, temples, and courtyards [44]. However, even though the characteristics of the site of occurrence of the species remain a key factor for their management, the low species diversity observed in this study could also be attributed to the loss of traditional beliefs. This gradually leads to the neglect of religious dogmas by local peoples as they relate to native species and to the development of a strong perception of risk. In the context of this research, risk perception can be defined as the development of a negative attitude towards large tree individuals that can lead to the abandonment of preservation acts or even to their elimination. Also, the number of LOTs observed per 100 km² reported per unit area is low (0.65 trees/km² for Abomey, 0.06 trees/km² for Ketou, and 0.22/km² for the Lokossa district) compared to the ratio of green space per capita (0.06–0.27 m²/inhabitant) in Benin [46] and the standard recommended by the World Health Organization [47] (WHO) (10 m²/inhabitant). This low number of LOTs corroborates the findings of the authors of [5], who deplore the situation of LOTs in human-dominated landscapes. Also, recent research [45] found about 682,730 large-diameter trees ≥100 years old in 198 urban areas in China, with only 0.36 trees per km² nationwide [35]. The density of large-diameter trees varies considerably, from 0.002 trees/km² in Tongyu County to 24.18 trees/km² in Macau [44]. These trees are mainly individually distributed in villages and urban areas and clustered in some plantation forests. The small number of LOT individuals found in the Ketou landscape (0.06 trees/km²) is a valuable indicator supporting the fact that the number of LOTs really depends on the importance of the traditional beliefs associated with them for their maintenance. Indeed, local residents from areas with royal dynasties (the people of Abomey) have protected the LOT individuals they came to see as cultural trees in conjunction with their local cultural systems. In this sense, trees older than 200 years are grouped together in royal palaces, princely courts, and traditional family spaces. The trees in these religious or cult places have been left relatively untouched because of the tradition of not cutting them down.

Beyond the myths and traditional customs that support the conservation of LOTs in the study area, there are ethnobotanical foundations that motivate the local people to manage them sustainably. Indeed, some LOT individuals were preserved both to maintain royal authority and to heal people when they were ill (physically and spiritually). They are therefore used in local recipes. The results also reveal that LOTs in the study districts are known to be used for handcrafts. For example, in the Abomey cultural landscape, dried fruits of Blighia sapida LOTs are used in cosmetics as a soap. The fibers from the pulp of the Adansonia digitata LOT are used to make rope for tying up livestock and traditional sponges. In this same landscape, the leaves of Adansonia digitata are used as a maceration to enhance male fertility. In the Ketou cultural landscape, Milicia excelsa wood is used to make human statuettes used to perform endogenous cult rituals, and its leaves were used as a decoction to treat spleen. In terms of food, the parts consumed from LOTs vary from one locality to another. For most species, they are leaves, fruits, roots, and bark. The LOT species whose leaves and fruits are the most consumed is Adansonia digitata. It is followed by Blighia sapida and Parkia biglobosa. Taking gender into account, this study found that both men and women know about LOTs. However, men have more local knowledge about LOTs, a fact explained by exclusive gender roles in the household. Indeed, local knowledge held by women is more related to the use of certain parts of LOTs in food and basic therapeutic care, while those of men were more extensive. Men in these cultural landscapes are primarily responsible for the health and spiritual well-being of the family, and for building and maintaining the home, and are therefore more familiar with the parts of LOTs used for multiple purposes (stem, root, bark, leaf, etc.). For example, in the Abomey district, men used A. digitata’s root and C. pentandra’s thorn to protect their families from evil spirits. In addition, the specific local names vary from one landscape to another, suggesting a long history of use, symbolization, and differences in how each LOT is perceived by local people. This may be an indicator of the level of integration of the species into their culture [48]. However, the study showed that despite their importance to humans, LOTs are in decline and face several threats. These are mainly anthropogenic and increase with population growth (urbanization, road development, etc.). Old trees are therefore felled by humans to satisfy their wood needs [49] and to build socio-economic infrastructure [50]. Furthermore, sacred and holy places representing the sites of occurrence of LOTs are threatened by several practices. For example, at the level of the study district, the sacred forests of Adakplame and Dogo in Ketou are highly threatened by communities who collect resources there to meet their daily needs (food, wood, and medicinal plants) and see these forest areas as fertile land for agriculture that can be used for a potential extension of their farms. The traditional beliefs that used to contribute to the conservation of old trees are also being challenged by monotheistic religions that demystify traditional practices and beliefs [42]. For the safeguarding of cultural identity, the adoption of these indigenous species for planting along the main boulevards of the cultural landscapes remains important. However, such efforts should focus on species for which the local peoples have developed a positive attitude based on the psychological, ecological, aesthetic, and spiritual benefits provided by the large old native species. This type of perception leads to the integral protection of species through the adoption and application of various traditional vetoes and taboos. In addition, some research suggested that the dieback of the oldest and largest baobabs in a short period of time may be associated with significant modifications of climate conditions, which affect especially southern Africa [51]. Exploring the interaction between social factors and bioclimatic pressures affecting LOTs will be important to determine areas in which such trees can exist in the future. Creating a seed bank and nurseries to ensure that reproduction is maintained long-term will be important. This is a prerequisite for the continuous production of saplings to replace losses from anthropogenic or natural causes, taking into account the culturally important species for each district.

4.2. Large Old Trees: Memories of Cultural Landscapes

LOT Individuals found in sites such as private residences, royal palaces, and the storefronts of community houses displayed the lowest percentage of “good” health status. Indeed, the frequent development and urbanization in such areas have exerted undue pressure on tree performance and survival. In the past, in addition to their aesthetic and ecological value, LOTs were seen by local peoples as intermediaries between spirits and human beings [52] In the African context, where plants occupy a fundamental place in several cultures, trees were considered children of the sky [29]. For example, the first Fon kings settled around 1625 in the shade of Parkia biglobosa trees and called this locality ‘Houawe’ (White Parkia). Also, on the Ehwe-adja plateau, Lokogba emerged before 1800 between some Milicia excelsa (Loko). Lagbahome and Lagbakada (two localities in the cultural landscape of Lokossa) were settled in the late 18th and early 19th century near some Adansonia digitata (Lagba) [53]. The founding of the kingdom of Allada was marked by the planting of a Ceiba pentandra tree [54]. Moreover, the preservation of some of these LOT individuals to the present day testifies to the fact that the choice of location of royal buildings was made according to these trees and their cultural interest. Most of the LOT individuals observed in the study are those venerated in cultural landscapes as monuments (LOT individuals in front of royal palaces or princely courts) or as Voodoo. The latter is an egregore (an entity close to the angel or to the collective unconscious) symbolizing all the gods or the invisible strength whose power or benevolence men try to conciliate. An affirmation of a supernatural world, it represents the set of procedures that allow humans to enter into a relationship with it [27] through the LOT species. The species that are most strongly protected by association with an egregore in the cultural landscapes studied are: Milicia excelsa, Antiaris toxicaria, Adansonia digitata, Ceiba pentandra, Blighia sapida, and Triplochiton scleroxylon. These species were planted as far back as the reign of certain kings and are like representations of certain local divinities. The individual of Blighia sapida in front of the palace of King Akaba (1708–1711), located in the district of Abomey surrounded by strangling ficus, represents the incarnation of the divinity “Aïzan” and is the place of traditional rituals for kings and dignitaries of Abomey after their enthronement. The king sat under this tree to listen to the warlords and chiefs of the Amazons make promises and swear on the “tribune of courage” to defeat the enemies. All these results corroborate the study by Savadogo et al. [55] that revealed that traditional natural resource management based on customary prohibitions, principles, and totems protected many species (animal and plant) from exploitation. The conservation of these veteran trees in cultural landscapes would require the integration of ancestral dogmas by taking into account the priority species that have marked the history and foundation of each commune, whether historical or not. In addition to these cultural considerations, in the current context of climatic variability, demonstrating the ecological potential of these veteran trees in cultural landscapes through further studies would be crucial for their sustainable maintenance. According to local custom in the three study districts, some LOTs such as Milicia excelsa serve spiritual functions and are not planted but rather established more through the natural dispersal of diaspores. In this sense, further research on the dispersal of these genera of LOT species could help to identify the faunal species associated with LOTs and thus assess the ecological role they play in biodiversity conservation.

5. Conclusions

This study, conducted in three cultural landscapes in the Guinean-Congolese zone of Benin, showed that LOTs have persisted under prolonged pressure from urbanization and environmental change. Although the diversity of LOT species is comparatively low, they continue to be an essential landscape component in the districts studied, and they are the plant base of the rural and urban heritage, knowledge of which should be deepened.

Although the construction of the royal palaces was based on the planting of some LOT species, the research methodology did not address the role of authority/power in the act of planting or the environmental or even economic importance of these species at the time. It also did not examine changes in LOT species management patterns during the era of colonial and post-independence political powers. Another methodological limitation lies in the fact that it was not possible to specify the old tree species to be prioritized for conservation in each cultural landscape. Indeed, in Benin, green space management is hampered by recurrent failures characterized by the planting of exotic species that need time to acclimatize when introduced far from their natural environment. For this reason, studies focusing on the prioritization of indigenous species by combining social and ecological criteria would be important in order to highlight, for each cultural landscape, those species on which urgent conservation and enhancement actions could be concentrated. Also, in addition to the cultural value addressed by this study, in order to highlight the contribution of LOTs to the national economy and the creation of jobs for young people, research focusing on their eco-tourism value can be assessed. Moreover, the evaluation of the ecological role played by these large old trees in the studied landscapes would be useful because it would open up new perspectives on the growth and development of the organisms (flora and fauna) associated with them.