@article {51,
	title = {Isozyme variation in oaks of the Apostle Islands in Wisconsin: Genetic structure and levels of inbreeding in Quercus rubra and Q. ellipsoidalis (Fagaceae)},
	journal = {American Journal of Botany},
	volume = {80},
	year = {1993},
	note = {199497074468Findings1. No species specific alleles were found 2. Allozyme variation was high, despite small geographic scale 3. Heterozygosity was lower than HW equilibrium. [My question: could this be b/c they were analyzing two spp together? this would produce inflated Het(expected)] 4. Nm for adults = 5.70, low for outcrossing, wind-pollinated, widespread spp 5. Acorn homozygosity ~ 2X adult homozygosity 6. HOWEVER, very low Fst and high genetic similarities suggest high gene flow 7. Likewise, morphological data suggest a genetic cline between mainland and islands This apparent contradiction {\textendash} low heterozygosity suggesting little gene flow; but high genetic identities, low Fst, and morphological intergradation {\textendash} may be a consequence of logging history. "Bottleneck" reproduction may account for lower heterozygosity in all populations.},
	month = {1993},
	pages = {1349-1357},
	abstract = {Isozyme variability was examined in populations representing the red oak complex (Quercus subg. Erythrobalanus) on an island archipelago and adjoining peninsula in Lake Superior, near Bayfield, Wisconsin. A concomitant study of morphometric variation described in the companion manuscript, revealed a continuum in leaf morphology extending from an interior mainland site to the outermost island. The existence of this clinal variation presented an ideal opportunity to examine the genetic structure of a hybrid population along with the putative progenitor species. Dormant leaf bud samples were collected from specimens of Quercus rubra L., Q. ellipsoidalis Hill, and their putative hybrids from three islands and two locations on the peninsula. Acorns were collected from some of these same trees from one peninsula location and two islands. Twelve putative enzyme loci from six enzyme systems were analyzed. Allele frequency data indicated little differentiation between populations. Mean F-ST values for the adult trees and acorns were 0.042 and 0.020. Genetic identities according to Nei ranged from 0.958 to 0.999. Despite these high levels of genetic similarity, the populations appeared to be highly inbred as indicated by positive mean F-IT values of 0.183 and 0.373 for the adult trees and acorns. Estimates of migration rate per generation (Nm) for the adult trees was 5.70, a value that is low when compared to estimates for other plant species with similar life history characteristics.},
	keywords = {-Biophysics, [26070-] Fagaceae-, ALLELE-FREQUENCY, Angiospermae-, Dicots-, Dicotyledones-, Ecology-: Environmental-Sciences, Enzymology-: Biochemistry-and-Molecular, Fagaceae-: Angiosperms-, Genetics-, Nearctic-region, Plantae-, Plants-, Population-Genetics: Population-Studies, POPULATIONS-, Quercus-ellipsoidalis (Fagaceae-), Quercus-rubra (Fagaceae-), Reproduction-, Spermatophyta-, Spermatophytes-, USA-: North-America, Vascular-Plants},
	author = {Hokanson, S.C. and Isebrands, J.G. and Jensen, R.J. and Hancock, J.F.}
}
@article {59,
	title = {Evidence for local adaptation in closely adjacent subpopulations of northern Red Oak (Quercus rubra L.) expressed as resistance to leaf herbivores},
	journal = {American Naturalist},
	volume = {142},
	year = {1993},
	note = {199497120675ArticleEnglish},
	month = {1993},
	pages = {928-936},
	abstract = {Many studies of herbaceous plant populations have illustrated the potential of adjacent subpopulations to adapt to local ecological conditions. However, the extent to which local adaptation on a small geographical scale can occur in outcrossing tree populations is not well understood. In this study, we reciprocally transplanted acorns from adjacent subpopulations of northern red oak (Quercus rubra L.) occupying north-, southwest-, and west-facing slopes within a 4-ha plot in a Missouri oak-hickory forest. The quantitative character we measured was leaf damage by herbivores on first-year seedlings, because it reflects resistance to insect herbivores-a quantitative trait that could be under different selective pressures in dissimilar microhabitats. We found that seedlings showed the least damage when planted at the site of the maternal plant. This finding provides initial but strong evidence of local adaptation and illustrates that selection associated with leaf herbivory may have a strong impact on the genetic structure of local tree populations. Such a result is unexpected for a widely outcrossing species on such a small geographical scale but indicates that genetic structuring is possible within other plant populations occupying heterogeneous environments.},
	keywords = {[26070-] Fagaceae-, [33000-] Animalia-, Angiospermae-, Animalia-, Animalia- (Animalia-), Animalia-: Animals-, Dicots-, Dicotyledones-, ECOLOGY-, Ecology-: Environmental-Sciences, Evolution-and-Adaptation, Fagaceae-: Angiosperms-, GENETIC-STRUCTURING, Genetics-, Missouri-: USA-, NATURAL-SELECTION, Nearctic-region, North-America, Nutrition-, Plantae-, Plants-, Population-Genetics: Population-Studies, Quercus-rubra (Fagaceae-), Reproduction-, Spermatophyta-, Spermatophytes-, USA-: North-America, Vascular-Plants},
	author = {Sork, V.-L. and Stowe, K.-A. and Hochwender, C.}
}
@article {112,
	title = {Ecology of mast-fruiting in three species of North American deciduous oaks},
	journal = {Ecology},
	volume = {74},
	year = {1993},
	note = {199395129424ArticleEnglish},
	month = {1993},
	pages = {528-541},
	abstract = {We conducted an 8-yr study of flower and acorn production in three species of oak in east-central Missouri (USA): white oak (Quercus alba), red oak (Q. rubra), and black oak (Q. velutina). The goal was to evaluate whether mast -fruiting, the synchronous production of large seed crops followed by small seed crops, is simply a response to weather conditions or is actually an evolved reproductivity strategy. In this paper, we address four specific questions: (1) Are annual fluctuations in acron crop size the result of synchronous production of acorns by individuals? (2) Are large acorn crops the result of large flower crops and/or high survival of those flowers to mature fruit? (3) To what extent do weather variables account for variation in acorn production among years? (4) Does acorn crop size correlate negatively with prior acorn production? Red oak and white oak showed a greater degree of mast -fruiting than did black oak. Within a species, individuals tended to produce large acorn crops in the same years, but each species differed in which years they produced large crops. The size of a given acorn crop was determined by both flower abundance and survival of flowers to fruit. Principal components and multiple-regression analyses were used to describe the relationship between weather variables and acorn production. The first principal component explained the largest amount of the variation in black oak (R-2 = 0.55) and red oak (R-2 = 0.89). In white oak, two principal components combined to explain 77\% of the variation in acorn production. The weather variables that were associated with these principal components included spring temperature (positive effect) and summer drought (negative effect). Past acorn production had a major impact on the size of the current acorn crop, with each species showing a different pattern. In black oak, the current acorn crop was negatively correlated with the crop 3 yr prior but positively correlated with the crop 2 yr prior. In red oak, acorn crop size 1, 2, and 3 yr prior had negative correlations with current acorn crop, while acorn crop size 4 yr prior was positively correlated. In white oak, there were negative correlations between acorn crop size and crop size 1, 2, and 4 yr prior but a positive correlation with the acorn crop size 3 yr prior. These data are consistent with the hypothesis that mast-fruiting species must store resources during some years in order to produce a mast crop. We discuss the possibility that these three species may have inherent cycles of reproduction that are modified by the impact of weather conditions, black oak with 2-yr cycles, white oak with 3-yr cycles, and red oak with 4-yr cycles. We conclude that the patterns of acorn production for black oak, red oak, and white oak are not simply responses to weather events but are also a function of prior reproductive events. This suggests that masting is an evolved reproductive strategy.},
	keywords = {(Fagaceae-), [26070-] Fagaceae-, ACORN-CROP-SIZE, Angiospermae-, Climatology-: Environmental-Sciences, Dicots-, Dicotyledones-, DROUGHT-, Ecology-: Environmental-Sciences, Fagaceae-: Angiosperms-, FLOWER-ABUNDANCE, Missouri-: USA-, Nearctic-region, North-America, Physiology-, Plantae-, Plants-, Quercus-alba (Fagaceae-), Quercus-rubra (Fagaceae-), Quercus-velutina, Reproduction-, REPRODUCTIVE-STRATEGY, Spermatophyta-, Spermatophytes-, TEMPERATURE-, USA-: North-America, Vascular-Plants, WEATHER-},
	author = {Sork, V.-L. and Bramble, J. and Sexton, O.}
}
