Since all conifers are wind pollinated, orchards located within the natural range of the species are susceptible to non-orchard sources of pollen (contamination). Contaminate pollen is considered to have a negative effect on both the orchards estimated genetic worth of the improved trait (for example growth) and the adaptive potential of seed orchard progeny. The objective of this first year project was to measure the extent and magnitude of Douglas-fir pollen contamination in two contrasting orchard sites on Vancouver Island. The mean level of contamination in the two coastal Douglas-fir seed orchards ranged from a low of 1.3% to a high of 100%.
Joe Webber and Michael Stoehr.
Webber, Joe E., Stoehr, Michael U.. 2005. Evaluating the protocol for quantifying pollen contamination on the genetic worth of conifer seed orchards - annual technical report. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report