Paramètres physiques d’évaluation du comportement des feux de végétation au Togo

Au Togo, le brûlage de la végétation est une pratique agricole et culturelle très courante. Mais, au-delà de certaines normes, le feu échappe au contrôle et devient néfaste aux écosystèmes et au cadre de vie. Cette étude se propose de comprendre le comportement des feux pour une meilleure maîtrise des brûlages. Spécifiquement, les paramètres de biomasse combustible, vitesse de propagation et intensité ont été analysés pour chaque régime de feu. Le dispositif expérimental est constitué de 81 parcelles (30x80 m²) installées dans les savanes d’aires protégées. La vitesse de propagation est plus élevée en savane soudanienne (11±1 cm/s) qu’en zone guinéenne (9±1 cm/s). L’intensité va de 1972±192 à 2218±357 kW/m. La vitesse et l’intensité des feux précoces sont faibles et à portée de contrôle comparativement aux feux tardifs et de mi-saison. La connaissance des paramètres d’occurrence devient une étape incontournable dans la gestion des feux. Dans un contexte tropical et face aux défis de gestion durable des écosystèmes forestiers et d’amélioration du cadre de vie, la prévention des feux incontrôlés et la maitrise des feux utilitaires exigent une bonne compréhension du comportement des feux.© 2015 International Formulae Group. All rights reserved.Mots clés: Intensité des feux, régimes de feu, vitesse de propagation, biomasse combustibleEnglish AbstractIn Togo, burning vegetation is very common as farming and cultural practice. But, beyond some standards, fires escape from human control and become harmful to forest ecosystems and the whole environment. This study aims at a better understanding of the fires behaviours. Specifically, parameters such as combustible biomass, propagation speed and intensity have been analyzed for each fire regime. The experimental device includes 81 land plots (30x80 m²) located in the savannas of protected areas. It is pointed out that the propagation speed is higher in sudanian savannah (11±1 cm/s) than guinean’s (9±1 cm/s). The intensity varies between 1972±192 to 2218±357 kW/m. Both speed and intensity are lower and easier to be under control in the case of early fire compared to middle-season and late fires. Knowing  better fire parameters becomes an important goal to be reached in order to well address fire issues in the country. In tropical context, the prevention of wildfires and the control of utilitarian fires depend on a better comprehension of fire movement. Fire control remains important in targeting a sustainable management of forests ecosystems and for the sake of  populations’ well-being.© 2015 International Formulae Group. All rights reserved.Keywords: Intensity of fires, fire regimes, speed of propagation, combustible biomas

Usefulness of Plant Biodiversity in the Cities of Togo

In an increasingly urbanized environment, the need for greenery and flowers is being more and more felt for esthetic reasons and ecological benefits. In Togo, more than six hundred species of horticultural plants are identified and composed of approximately 59% of dicotyledons (49 families, 145 genera, and 315 species) and 37.37% of monocotyledons. Pteridophytes and gymnosperms account for less than 6%. The spectrum of morphological types indicates that herbs are account for 55%, while trees and shrubs represent 15%. More than 50% of the species of this flora is exotic horticulture. A species distribution is made according to their decorative parts and their place of use. Across the country, 55 plantings are recorded and unevenly distributed in cities. Apart from their ornamental purpose, ornamental plants are used for feeding, traditional and industrial cosmetics in psychotherapy, horticultural therapy, and in traditional and conventional medicine. In this study, 79 species from 39 families are reported as medicinal plants. The Apocynaceae and Fabaceae (six species), the Euphorbiaceae and Liliaceae (five species), the Arecaceae and Verbenaceae (four species) are the best represented families. Production systems in ornamental horticulture in Togo are very diverse in terms of speculation, access to land (variable surfaces, direct or indirect forms of tenure, acquisition methods, land use, etc.) and socio-economic profiles of farmers (men, women, young, old, people with little or no qualifications, rural to urban, etc.). The family horticultural production system, which represents over 90% of 55 horticultural farms of this study, is the main production system. It is characterized by areas of less than 0.1 hectare and farms in relative land insecurity (97% of land used belongs to the state). Throughout the system, there is a salaried labor representing 5–8% of turnover. Temporary and permanent employees are paid on weekends or at the end of the month. Farmers use gardening equipment and processing plant more or less modern including clippers, shears, pruners, and sprayers. Production units provide direct employment (more than 3 employees per unit) and directly to several hundred people. Horticulture in urban and peri-urban areas improves the living conditions of farmers (income) and the population (embellishment of streets, maintenance or creation of green area buffer) despite some negative externalities associated particularly with the use of prohibited pesticides and uncontrolled use of spaces along the roads. Its survival is threatened by many constraints, including the extension of urban housing and road building. In Togo, beneficial effects of ornamental horticulture may be more noticeable if the political authorities, private stakeholders, and the researchers work together to organize the sector. It could thus participate effectively in the formal economy and the emergence of true development plans at the municipal level

IN VITRO MICROPROPAGATION OF NAUCLEA DIDERRICHII (DE WILD &T. DURAND) MERRILL: EFFECT OF NODES POSITION ON PLANTLETS GROWTH AND ROOTING

In tissue culture, the reactivity of explants in culture depends on their position on mother –plant or their physiological development level. This study aims to determine the regenerative potentialities of nodes according to their position for suitable in vitro micropropagation of N. diderrichii’s seedlings. Thus the effect of uninodal explants position of Nauclea diderrichii on seedling growth and rooting was studied in vitro. Three types of nodes (apical, middle and basal node) excised from two months old seedlings were tested using Woody Plant Medium (WPM) containing 30 g/L of sucrose and solidified with agar-agar at 8 g/L. The mean number of roots and shoots per plant was scored as well as the shoots and roots length was measured after six weeks of culture. Apical nodes produced seedlings with highest number of roots (6.80 ± 2.44 roots / plant) followed by basal (5.70 ± 2.68 roots / plant) and middle nodes (4.50 ± 2.12 roots / plant). But middle and basal nodes produced the best number of shoots (1.90 ±0.31 shoots / plantlet) than that obtained with apical nodes (1.30 ±0.57 shoots / plantlet). Seedlings obtained from apical nodes expressed efficient growth (4.70 ± 1.70 cm) compared to the middle (2.18 ± 0.97 cm) and basal nodes (2.33 ± 1.08 cm). So, for a rapid in vitro production of N. diderrichii’s seedlings, apical nodes of in vitro plants are more suitable

Nitrogen Moderate Rates’ Effects on the Performance of Cocoa Seedlings (Theobroma Cocoa Linn.) in the Forest Zone of Togo (West Africa)

The cocoa trees nutrient requirements coverage, especially in nitrogen (N), remains essential for a better growth of the seedlings. The objective of this study was to determine the effects of the moderate nitrogen doses on the agronomic performance of the nursery cocoa seedlings in Togo’s forest zone. Trials were conducted in a complete randomized plot design with four replicates to identify the optimal complementary nitrogen dose helpful for better growth and nutrition of cocoa seedlings. The doses tested were 0; 0.5; 1 and 1.5 g.plant-1 of urea (46% N). The results showed that the doses of 0.5 and 1 g.plant-1 were the most likely to provide the best agronomic performance of nursery cocoa seedlings in the forest zone of Togo. However, the dose of 1 g.plant-1 was optimal for good growth and balanced nutrition of cocoa seedlings and would therefore be recommended for the management of cocoa nurseries in the area

PERCEPTIONS, TENDANCES ET PRÉFÉRENCES EN FORESTERIE URBAINE: CAS DE LA VILLE DE LOMÉ AU TOGO

Opportunities for forestry in urban areas can be analyzed in relation to urban, their lives, their priorities and their views on urban trees, then consider the conditions under which trees can promote them. This study is an inventory of green spaces in Lomé. It evaluates its floristic diversity and identifies the population’s perceptions and expectations in urban forestry. The inventory of green spaces made indicates that each inhabitant of the urban agglomeration of Lomé has 0.75 m² of green space while is less than 10 m² recommended by the World Health Organization (WHO) in urban areas. In total, 93 species belonging to 79 genera and 47 botanical families were identified. People perceive very well the role and the importance of trees in urban and suburban areas. The main role is recognized embellishment (61%), to which are added other benefits such as aesthetics (33%), improvement of living conditions (4%). Only 2% of urban trees are used as medicine in Lomé. Sixty-one percent of respondents stated attend greenspace. These concerns of the people are not to be neglected and should be taken into account in future development planning actions in urban and peri-urban forestry