Vegetation structure of a heavily grazed range in northern Kenya: tree and shrub canopy

acacia tortilis agroforesteria agroforesterie agroforestry botanical composition brousse canopy commiphora composition botanique couvert cubierta de copas ecologia vegetal grewia lippia matorral parcours plant ecology rangelands scrub scrublands silvopastoral systems stand characteristics stand structure tierras de matorral tierras de pastos vegetation verbenaceae vernonia woodlands