Pollination and seed production in western white pine

The reproductive biology of western white pine (Pinus monticola Dougl. ex D. Don) at the Saanich seed orchard (SSO; a coastal seedling seed orchard) and the Kalamalka seed orchard (KSO; an interior clonal seed orchard) is described. Seed-cone development and morphology determine seed potential and affect filled seed production. Seed potential was high, commonly over 200 seeds per cone and filled seeds per cone averaged 50-60 at both orchards in 1999 from open pollinations combined with operational supplemental mass pollinations (OP-SMP). Filled seeds per cone at SSO in 2004 averaged 115 with open pollinations and OP-SMP. About 30% of ovules aborted before pollination. Another 25% aborted probably because of self-incompatibility at fertilization. Seed efficiency (SEF) was only 5% at KSO with open pollination but increased to 30% with OP-SMP. SEF was the same at SSO with or without OP-SMP. Reproductive success was very low at KSO without OP-SMP but increased to about 10%, similar to that of SSO, with OP-SMP. The optimal time for control pollinations was at cone stages 4 and 5 and optimal amount of pollen per pollination bag was 0.3-0.4 mL. Western white pine is a very good seed producer and can be easily managed in seed orchards to give very high seed production per cone and per tree.