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In Niger, literature from the years 1990–2020 shows a rapid regression in the surface areas of forest, an abundant regeneration of trees in some cultivated areas, and a sharp increase in the consumption of wood energy in cities and the countryside, with this wood increasingly coming from parklands. This study, carried out in 2015–2019 on the outskirts of Niamey, aimed to assess the economic benefits for households of parkland fuelwood production and the ecological state of the parklands. Surveys were carried out among 90 farmers to assess the contribution of fuelwood to their household income. Semi-structured interviews with focus groups were conducted in 3 villages to determine farmers' strategies and practices. The inventory of the trees in the parklands was carried out in 3 villages (5000 ha per village). Most rural households have an income diversification strategy to cope with the vagaries of agricultural production. Among these revenues, the sale of fuelwood occupies on average a small place (4 to 10%). To explain their reduced use of assisted natural regeneration (ANR) for the restoration of parklands, farmers point to the difficulty in exploiting wood pruned from their trees due to conflicts of use with livestock herders, taxes and fines from environmental services agencies. Trees and shrubs in parklands have a low diversity (24 species) and low density (5–8 trees/ha). The low density of young trees indicates that during the past decade, there have been fewer efforts to enrich parklands compared to the 1980s, when ANR projects were first implemented. The 3 parklands studied are in the process of becoming severely degraded because dead old trees are no longer replaced through ANR. The Economic importance of fuelwod in family resources is not a sufficient trigger factor for farmers to restore their parklands but could support village's interest for sustainable management of natural forests. These results should serve to alert public authorities and aid organizations that research and development actions must be launched to reverse this deterioration trend in parklands.

On the outskirts of the city of Bangui, the capital of the Central African Republic, fuelwood production, slash-and-burn agriculture and artisanal timber exploitation are causing deforestation and forest ecosystem degradation. Within the framework of the REDD+ Component of the South-West Regional Development Project, the implementation of Assisted Natural Regeneration during weeding (ANRw) in the slash-and-burn system was proposed and set up by 23 volunteer farmers on 24 fields with an average area of 0.22 ha in two villages (Boteke and Salanga). The objective of the study was to characterise the floristic structure of the juvenile woody vegetation resulting from ANRw in these two villages. More specifically, it aimed to: 1) describe the methods used to inform and raise awareness amongst farmers who volunteer to practise ANRw; 2) identify the main species conserved by the farmers; 3) identify the reasons or factors that motivated farmers to choose these species; 4) identify the biological and ecological characteristics of these species; and 5) evaluate the height growth of young trees preserved by ANRw over a 14-month period. The third inventory of the 24 plots (volunteers' fields) gave 1,668 woody plants preserved by ANR on 5.35 ha (312 trees ha−1), divided into 42 genera, 47 species and 23 families. These results show that ANRw is a simple technique to implement and can help maintain trees in fields in areas where pressure on the forest is high. In the supported villages, communities have shown an interest in applying this technique to reintroduce trees in the fields. This technique should be popularised in other places to improve the sustainable management of anthropized forest landscapes. In addition, volunteers who have tested ANRw say they are willing to continue practicing it. However, despite this genuine initial enthusiasm, this restoration drive will need to be monitored and supported due to the current context of extreme poverty and economic, social and political instability.

La regeneration naturelle assistee, technique utilisee pour favoriser le developpement du potentiel adventif et du potentiel seminal des arbres, est un mode de reproduction adopte de nos jours pour renouveler et perenniser les formations forestieres. La presente etude a ete realisee dans les plantations de la foret classee de la Lama, situees entre 6°55' et 7°00' de latitude Nord et entre 2°4' et 2°12' de longitude Est. Elle vise a proposer une technique de regeneration naturelle assistee peu couteuse adaptee aux peuplements de teck installes sur des vertisols hydromorphes. Trois methodes de regenerations naturelles assistees ont ete testees sur quatre types de sols (vertisol argilosableux, vertisol argileux, vertisol argilo-calcaire et vertisols argilo-calcaire superficiel). Pour chaque traitement sur chaque type de sol, deux placeaux carrees de 100 m2 ont ete materialises avec chacun huit placettes de 4 m2. La regeneration a ete inventoriee dans chaque placette et des releves ont ete effectues par rapport au nombre, hauteur et circonference au collet des jeunes plants. L’evaluation des couts de la methode a ete realisee grâce a une comptabilite analytique reguliere prenant en compte toutes les depenses d’installation et de maintenance des parcelles experimentales. La densite, hauteur et circonference au collet varient significativement en fonction des types de sol. Toutefois, les plants sont plus developpes en hauteur et en circonference au collet dans les interlignes que sur les lignes. La regeneration sur sol non travaille est le moins couteuse et donc celui a recommander aux gestionnaires des teckeraies de la Lama. Assisted natural regeneration is a technique used to promote the development of the seminal potential of trees. Actually, it is a mode of reproduction adopted to renew and sustain the forests. This study was carried out in the plantations of the Lama reserve (between 6° 55' and 7° 00' north and between 2° 4'and 2° 12' east). It aims to propose an inexpensive assisted natural regeneration method adapted to teak stands installed on hydromorphic vertisols. Three assisted natural regeneration methods were tested on four soil types ((clay-sandy vertisol, clay vertisol, clay-limestone vertisol, and superficial clay-limestone vertisols). For each treatment about each type of soil, two square plots (100 m2) were materialized with eight plots of 4 m2 each one. Regeneration was inventoried in each plot and data are collected about number, height, and circumference at the neck of seeding. The production costs were assessed through regular cost accounting taking into account all the installation and maintenance expenses of the experimental plots. From the results, density, height, and collar circumference vary significantly with soil types. However, the seedlings are more developed in height and circumference at the collar in the interlinings than on the lines. Regeneration on unworked soil is the least expensive and therefore the one to recommend to managers of teak plantations of the Lama.

East African montane forests have been subjected to heavy logging, particularly of Ocotea usambarensis Engl., formerly one of the dominant tree species of moist mid-altitude forests. At Mt. Kenya, logging was suspended in 2000 after a conspicuous decline in population size, but the success of this conserva- tion measure has not yet been evaluated. Given that a management scheme of O. usambarensis forests based on vegetative regeneration has been suggested, we hypothesized that natural regeneration mainly by root suckers would be sufficient for a recovery of this species. Demography and regeneration (both sexual and vegetative) of O. usambarensis were studied in 45 study plots between 1700 and 2500 m asl along a gradient of historical logging intensity, while taking altitude and light incidence into account as predictor variables. The diameter distribution showed a high percentage of old individuals and rather low recruitment in O. usambarensis . In heavily logged areas (removed basal area >25 m 2 ha 1 ), smaller trees (130 cm high) were completely absent. The number of seedlings was low and inde- pendent of logging intensity. It increased with higher light incidence. The number of root suckers was 5.6-fold the number of seedlings, underscoring the importance of vegetative reproduction. However, number of root suckers and logging intensity were negatively correlated. We conclude that regeneration of O. usambarensis at Mt. Kenya is generally low and negatively influenced by historical logging. There- fore, natural regeneration is inadequate for the recovery of this valuable timber species, and additional conservation measures such as enrichment planting should be considered.

Made available in DSpace on 2018-12-11T16:42:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-08-15 The invasive potential of a species is related to the interaction between genetic and environmental characteristics, as climatic conditions and native vegetation, reflecting the species adaptation to local conditions. An ecologically-adapted alien species can alter diversity and structure of forest ecosystems. This study assessed the invasiveness potential of eight commercially important Eucalyptus species in the germination and early establishment phases in southeastern Brazil. The first experiment evaluated seed germination under controlled temperature and air humidity conditions testing six substrate water potentials. The second experiment was conducted in pots to evaluate seed germination and seedling mortality under rainfed and irrigated regimes. Nine field trials were set up in the third experiment in six locations. In each trial, 80 plots of 1 m2 were installed with half the plots undisturbed and half where preexisting plants and litter were removed. In the first experiment, Eucalyptus taxa differed significantly in seed germination for substrate water potential ≥-0.6 MPa. No germination was found for any taxa at -0.8 MPa substrate water potential. In the second experiment, differences in germination between species and water treatments were observed 21 days after sowing. No mortality was found in the irrigated treatments. No seedling mortality was observed in the rainfed treatments when the relative air humidity was higher than 85%, even during a dry period of 45 days. By contrast, seedling mortality was observed for all taxa in all the rainfed treatments when relative air humidity fell under 80%. In the third experiment, germination and seedling establishment of Eucalyptus species was always very low. The non-Eucalyptus species showed differences in germination between trials and soil exposures. Our results showed that soil and air moisture were major drivers of eucalypt germination and initial establishment in controlled conditions. However, under field conditions additional factors such as competition of non-Eucalyptus species and seedlings predation drastically limited eucalypt establishment suggesting low ecological adaptation of Eucalyptus sp. as an invasive species. IPEF - Instituto de Pesquisas e Estudos Florestais, Avenida Pádua Dias 11, Caixa Postal 530 UNESP-Universidade Estadual Julio de Mesquita Filho/FCAV-Faculdade de Ciencias Agrarias e Veterinarias, Via de Acesso Prof. Donato Castellane S/N CIRAD UMR EcoandSols USP-ESALQ Departamento de Ciências Florestais, Av. Pádua Dias, 11 Caixa Postal 9 UNESP-Universidade Estadual Julio de Mesquita Filho/FCAV-Faculdade de Ciencias Agrarias e Veterinarias, Via de Acesso Prof. Donato Castellane S/N