REPRODUCTIVE INDICATORS OF Pinus leiophylla Schltdl. et Cham. OF THE ANGULO RIVER BASIN, MICHOACAN

Abstract

Woodland loss is a serious problem in Mexico. Species such as Pinus leiophylla with low wood quality, and that offers a non timber product, survive in greater proportion and can be important in the conservation of forests. Since this specie grows in mixed stands and populations are conformed by scattered trees, their reproductive potential may be low. Thus, a cone analysis was made in order to find reproductive indicators and possibility of success in propagation programs. Ten cones were collected from each of the 48 assessed trees in four representative routes of the natural distribution of this species in the Southwest of the Rio Angulo watershed in Michoacan State. The mean values by cone were: 61 seeds as potential, 72.9% of abortive ovules and 27.1% of developed seeds, this is 16.6 per cone, of which 7.3% were filled, 89.2% empty and 3.6% with insect damage, this means only 1.2 filled seeds per cone or 1.97% of filled seed efficiency. Mean reproductive efficiency was 2.49 mg of seed by gram of cone. These values are low compared to similar reports in the same and in different conifer species. Cone volume has a positive correlation with seed potential but negative with filled seed per cent. Selection of the largest cones does not produce the biggest seed harvest. These results can be due to a low population density and scarcity of pollen.