Article révisé par les pairs
Résumé : A study aiming the establishment area-species relationship considering the age of the fallow has been led in the perimeter of the natural forest reserve of Kigwena (Burundi). According to the systematic inventory of all vegetal species present in three classes of fallows (0-2 years, 3-5 years and more than 5 years), equations of tendency curves obtained are respectively: y = 4,58 Lnx +19,7, y = 6,70 Lnx +4,99 and y = 7,22 Lnx+11,63. The regression is therefore very maid with raised coefficients in any case (R 2 = 0,97). Values of c and z obtained show that, on an even surface of 1 m 2, the highest specific diversity is in recent fallows (c = 18). According to Arrhenius equation, species-area relationship in fallows of our study (0-2 years, 3-5 years and more than 5 years) are respectively: S = 18A 0, 16, S = 8A 0, 31 et S = 11, 8A 0, 26.