The demographic genetic substructuring of local Fagus crenata populations at Ogawa Forest Preserve, Ibaraki Prefecture, central Honshu, Japan, was analyzed by means of demographic parameters and genetic markers using protein polymorphisms (allozymes). All individuals, including seedlings, various sizes of juveniles, and adult trees within two transects were mapped; size‐class structures were analyzed based on DBH and DGH measurements, and their genotypes determined for 11 different allozyme loci (a total of 46 alleles), i.e., Aap1(3 alleles), Adh (3), Amy2 (6), Dia (4), Fum (3), Got1 (5), Got2 (3), Lap (6), Pgi (4), Pgm1 (4), and Pgm2 (5). Critical analyses were conducted to test whether genetic substructuring patterns in these two transects are correlated with the underlying environmental regimes of the habitats. Measurements of relative light intensity, soil moisture, pH, and C‐N content were made for each block in the two transects. Principal component analyses (PCA) of the environmental variables revealed that two components (Z1 and Z2) were closely related to variations in light intensity and soil moisture. The projection diagrams obtained by the environmental variables were then overlaid with the spatially localized patterns of size‐classes and genotype distributions of 11 allozyme loci examined. The results revealed that genetic variations are pooled in the juvenile trees of certain size‐classes, consisting of overlapping generations which occur in the particular sites characterized by environmental regimes. Throughout the regeneration processes, new genetic diversities are introduced through seedlings with new genotypes into the population.

We investigated chronological changes in allozyme diversities in Fagus crenata populations by means of size‐class discriminations, using allozyme variations in two transects established in a mixed beech‐oak forest in the Ogawa Forest Preserve. All individuals within transects were divided into six size‐classes based on their diameters: class 0, seedlings; class 1, juveniles <5 mm; class 2, 5 < juveniles < 10 mm; class 3, 10 < juveniles <25 mm; class 4, 25< juveniles <600 mm; class 5, 600 mm

We developed a method for producing restriction landmark genomic scanning (RLGS) profiles of largesize genomes, such as those of higher plants or amphibians using a restriction trapper. Use of the conventional RLGS method is limited to genomes smaller than 3 x 10 9 bp, because the larger genomic DNAs, especially those of more than 1 x 10 10 bp, produce high background due to incorporation of radioactivity at non-specifically damaged sites. Our new method reduces the background levels by reducing genome complexity to 1/200-1/300 using a purification step to enrich DNA fragments carrying specific restriction landmarks at their ends using a restriction trapper. This step makes it possible to obtain RLGS patterns of larger genomes. Our paper describes the practical application for the RLGS method using a restriction trapper with the pine tree genome (3 x 10 10 bp/haploid genome; Pinus koraiensis Sieb. et Zucc.) as an example.