Historical record of the problem of the natural repopulation of the linaloe Bursera linanoe (La Llave) Rzedowski, Calderón & Medina

Abstract

The linaloe it is a tree that produces a fine resin. Produces essential chemical, aromatic, cosmetic, pharmaceutical, and industrial compounds of high commercial value, only grows in Mexico, in the middle portions of the Papaloapan and Balsas River basins. The excessive use of its wood and its fruit to obtain essential oil, the destruction of the low forest where it lives, disorderly grazing and some environmental and biological constraints have generated an excessively low, discontinuous and sparse natural repopulation. The study of the causes of this threatening scenario is scarce and discouraging, insufficient to propose appropriate solutions. This motivated the present analysis of silvicultural conditions, present regeneration and basic aspects of reproductive biology in three natural populations from Oaxaca, Puebla and Guerrero. Very few trees ha-1 (36 to 45) were found, with few females (35%). Diameters ranged from 5 to 35 cm, with maximum heights from 10 to 14 m. The regeneration in Chiautla was 21 individuals ha⁻¹, while in Los Cués and Xalitla no regeneration was found. When reviewing the reproductive biological factors of the species, it was observed that the stages of flowering, fruiting and seed dispersal are seriously limited by low rainfall and the occurrence of these in short, rare and irregular pulses. The flowering potential is high and increases with the diameter of the female trees, but the conversion of flowers to full and viable fruits produced is limited by the rainfall regime. Germination is notably decimated by the frugivorous activity of birds and mammals. The new plants are trampled and browsed by livestock and wild mammals. The simultaneous occurrence of some or all of the limitations dangerously endangers populations. Assisted propagation is suggested to guarantee the permanence of the species.