Ponderosa pine cones from 10 areas in Arizona were collected prior to natural seed dispersal and dissected to determine the number of sound, hollow, and insect-damaged seeds in each cone. Total and sound seed yields per cone did not vary significantly among areas but did vary significantly among trees within each area. Numbers of hollow and Megastigmus-infested (Hymenoptera: Torymidae) seeds varied significantly among areas and trees within areas. Numbers of sound seed increased significantly with increasing cone length but did not change with increasing numbers of cones per cluster. The percentages of Megastigmus-infested seed did not change significantly with increasing cone length or number of cones per cluster.
Schmid, J. M.; Mata, S. A.; and Mitchell, J. C.
"Number and condition of seeds in ponderosa pine cones in central Arizona,"
Great Basin Naturalist: Vol. 46
, Article 10.
Available at: http://scholarsarchive.byu.edu/gbn/vol46/iss3/10