Microsatellite analysis was used to examine parentage and spatial distributions of 62 adult bur oaks Quercus macrocarpa, and 100 saplings in a single stand. Using genotypes scored by PCR products at four microsatellite loci, we determined that 94 saplings matched at least one parent in the stand. Saplings often occur as dense clusters of half‐sibs around the presumed maternal parent, and only four adults were seed parents to a large proportion of the saplings sampled. A stump apparently was the seed parent of the largest cluster of half‐sibs, which occupied a sizeable light gap opened up by the death of their maternal tree. Approximately half of the saplings appeared to have grown from seeds that had not been removed after falling from the tree, and half from seeds that were dispersed beyond the crown of their maternal parent. Long‐distance seed dispersal may be more common than has been previously reported. Extremely high levels of long‐distance pollination were indicated, and pollen donors within the stand were generally distributed randomly around maternal trees. More than half of the saplings had paternal parents outside of the stand. This study demonstrates the utility of microsatellite analysis for studying mating systems, seed dispersal and seedling establishment in natural plant populations.

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The objective of this study was to ascertain the usefulness of polymerase chain reaction (PCR)-based microsatellite analysis for studying pollination and parentage in a wind-pollinated temperate tree. A small insert genomic library of the bur oak (Quercus macrocarpa) was constructed and screened for the presence of (CA/GT) n and (GA/CT) n repeats. The proportion of positive clones yielded estimates of 3×10(5) such dinucleotide repeats per genome, roughly comparable to abundances reported in other eukaryotic genomes. Thirteen positive clones were sequenced. In contrast to mammalian genomes, the (GA/CT) n motif was more abundant than the (CA/GT) n motif in these clones. The (GA/CT) n repeats also showed longer average repeat length (mean n=16.2 versus 7.3), suggesting that they are better candidates for yielding polymorphic genetic markers in oak genomes. Indeed, a survey of adult bur oaks and offspring in a small stand in northern Illinois at 3 of these (GA/CT) n microsatellite loci revealed Mendelian inheritance and extremely high levels of polymorphism, with the number of alleles at each locus ranging from 11-20 and heterozygosity ranging from 0.66 to 0.75. These results, indicating that (GA/CT) n microsatellites are both abundant and highly polymorphic in the bur oak genome, suggest that such genetic markers have tremendous potential for applications for studies of parentage, pollination and dispersal in temperate trees.

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To determine the usefulness of lodgepole pine in windbreak plantings in the Northern Great Plains, seeds were collected from 25 locations in the western United States and Canada and planted at the Northern Great Plains Research Laboratory ( USDA-ARS) in Mandan, North Dakota. Survival, height, crown diameter, crown density, and Petrova damage were recorded over a 15 yr period. Once established, lodgepole pines were hardy and drought resistant, and there was no mortality after the first 6 yr. Average annual growth was 29 cm. Our results suggest that lodgepole pines may be selected for survival after 2 yr of growth in the field and selected for height after 5 yr. Seed sources from southwestern Montana, northern Idaho, and southern Canada had the best overall performance as measured by good survival, superior height, and narrow crowns. West. J. Appl. For. 13(1):5-11.