Trees may be classified subjectively in three classes as “poor” , “average” and “qood” , as described for
other species of conifers (e.g. Dobbs et al. 1976, Robbins 1983 a). If necessary, the yield of seeds from
cones may be estimated by cutting longitudinal sections of a sample of cones, using a cone cutter or machete
(Dobbs et al. 1976, Robbins 1983 a). The ratio of full seeds per cone to full seeds exposed on a cut
surface in P. merkusii has not been reported in the literature and may vary according to provenance. For
other tropical pines, P. caribaea and P. oocarpa/tecunumanii, a ratio of from 10:1 to 20:1 applies (Robbins
1983 a, 1983b. Only full seeds should be counted; undeveloped seeds occurring near the tip or base of the