DYNAMICS AND NATURAL REGENERATION OF WOODY SPECIES IN FARMED PARKLANDS IN THE SAHEL REGION (PROVINCE OF PASSORE, BURKINA-FASO)

There are various indications that the farmed parklands in the Sahel region are degrading. This study demonstrated that tree densities are decreasing rapidly and small diameter classes are rare. Two-year monitoring of natural regeneration on 30 trial plots of 400 m2 showed that shoots (regeneration from rootstocks) are abundant (up to 935 ha-1), but originate from few shrub species, mainly Combretum glutinosum, Guiera senegalensis and Piliostigma reticulatum. Whereas shoots survived the dry season, seedlings (from sexual regeneration) were few (up to 360 ha-1 in the rainy season) and did not survive the dry season. Most indigenous trees produced seedlings during the rainy season. The presence of seedlings seemed to be determined mainly by moisture availability, the presence of seed trees and the intensity of fruit exploitation. Seedling survival was poor, mainly because of the combined effects of drought and browsing. To maintain indigenous fruit trees in the parklands the young plants require watering in the dry season and protection against livestock and from damage during field clearing and weeding.