Current issue: 54(2)
As part of a multi-year monitoring study of pollination dynamics in a second generation Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seed orchard, we estimated with the aid of eight microsatellite markers three important reproductive biology characteristics affecting the genetic worth and diversity of seed crops; namely parental reproductive success, pollen contamination, and selfing rate. The obtained results were compared to those from two previous years to gauge appropriate seed crop management practices and ultimately allow approximate generalization of seed crop genetic quality. We determined that 80% of parental gametes were produced by 52% of the parents, 13% of paternal gametes resulted from pollen contamination (i.e., gene flow), and 12% of the seed were the product of selfing. The obtained results were in line with those observed for 2005 and 2009 where 80% of gametes being produced by 37–48% of the parents, 10–18% pollen contamination, and 15–17% selfing rate. The observed reproductive biology parameters differences are attributable to the various crop management practices implemented (i.e., bloom delay and supplemental-mass-pollination) across years and calls for justification due to the observed minimal differences on seed crops genetic quality.
The article includes observations on forest site types in Canada and the United States, with special emphasis on forests of lodgepole pine (Pinus murrayana, now Pinus contorta Douglas ex Loudon) which the author considers a species that can become a favourite exotic tree species in Finland. Some notes are made also about Jack pine (Pinus banksiana Lamb.) and Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) forests. The author was not able to make a systematic forest type investigation, because the journey was made on another purpose. The article describes the vegetation and climate of the visited areas, and divides the forest site types in three groups: Dry forest site types, moist forest site types and grass-herb site types. The vegetation and plant species on several subtypes are described in detail.
The volume 34 of Acta Forestalia Fennica is a jubileum publication of professor Aimo Kaarlo Cajander.