Reproductive phenology of Pilgerodendron uviferum (D. Don) Florin on Chiloé Island, Chile

Abstract

Pilgerodendron uviferum is a conifer species of high ecological importance, which after several centuries of extensive burning and indiscriminate felling presents conservation problems. The lack of knowledge about critical aspects of their reproductive cycle represents currently an important gap to support forest restoration projects, particularly in optimal seed collection times and the possible interruption of pollination and/or seed dispersal mechanisms. In this work, we study the reproductive phenology of P. uviferum on Chiloé Island during three years, with the aim of identifying their reproductive stages and occurrence over time. The male and female reproductive structures of P. uviferum were quantified in each summer, autumn, winter and spring season, classifying them according to their state and phenophase. P. uviferum has a reproductive cycle limited to a ca. 1 year. In male and female trees, it is observed that more than 50 % of the branches present differentiation of the reproductive buds, of which more than 75 % manage to disperse the pollen and 80 % of the female cones are pollinated. However, seed dispersal is considerably low, being zero the first year. The reproductive success largely depends on female trees, since male trees showed a regular pattern of cone production. The reduction in viable seed harvest is one of the most important ecological problems in conifers and has implications for seed production for restoration programs.