Fallen logs are the main regeneration sites for Abies sachalinensis (Sachalin fir) in subboreal forests in Japan. We surveyed the spatial genetic structure of different demographic stages in a 4.29‐ha natural population of A. sachalinensis . Genetic structure was significant at short distances throughout all stages in this wind‐dispersed conifer. To evaluate the effects of fallen‐log‐dependent recruitment on demography and spatial genetic structure, we conducted parentage analysis of offspring with highly polymorphic nuclear simple sequence repeat and chloroplast simple sequence repeat markers, and developed a new hierarchical Bayesian model to estimate the effects of mother trees and fallen logs on seed dispersal and offspring recruitment. Combined application of nuclear and chloroplast simple sequence repeat markers allowed us to unambiguously identify mother trees of most offspring (> 90%). Female reproductive success was extremely skewed; a few adults produced most of the offspring on fallen logs. Limited distance of effective dispersal and recruitment was seen in the parentage analysis and modelling estimation. These recruitment characters of A. sachalinensis , with a fallen‐log‐dependent recruitment process, may result in significant genetic structure in early demographic stages.

s from the Journal of The Japanese Forest Society J For Res (2007) 12:152–160 © The Japanese Forest Society and Springer 2007 DOI 10.1007/s10310-006-0275-y

The genetic diversity and genetic structure of plant populations are influenced by processes of regeneration. Assessing the genetic composition of populations regenerated by different modes is important for successful forest management and conservation. In this study, we compared the genetic diversity and genetic structure of six populations in mixed stands with those of four post-fire stands of the noble hardwood species Betula maximowicziana. We collected plant tissues from 491 adults and 266 seedlings, germinated from soil samples, for a total of 10 populations, and genotyped them using 11 microsatellite loci. Genetic diversity parameters (e.g., HE, Rs, FIS) in the post-fire stands were similar to those in the mixed stands. In contrast, other parameters, including the number of private alleles (PA), the number of loci showing significant linkage disequilibrium (LD) and effective population size (Ne) differed between the mixed and post-fire stands. The average PA, LD and Ne values were 1.2, 2.0 and 315.7, respectively, for the mixed stands, and 0.3, 5.0 and 282.2, respectively, for the post-fire stands. Evidence of a significant bottleneck was detected in two of four adult populations in the post-fire stands, possibly as a result of a catastrophic founder effect due to fire disturbance on their genetic constitution. Buried seed populations maintained the same level of genetic variability as adult populations, but with lower genetic differentiation among them. Spatiotemporal gene flow, characterized by wind-mediated dispersal and the persistence of viable seeds in the soil, are key factors maintaining the genetic diversity of B. maximowicziana populations. Our study reveals that post-fire stands and buried seeds will be useful genetic resources in the future.

Resistance of the Japanese larch ( Larix kaempferi ) (Lk), the Kurile larch ( L. gmelinii var. japonica ) (Lg), and their F 1 hybrid (Lg × Lk) to bark stripping by sika deer ( Cervus nippon yesoensis ) were studied in a forest in Hokkaido by cafeteria tests. Several sets of logs prepared from Lk, Lg, and Lg × Lk were fed to the deer. The stripped areas of logs significantly differed between the Lk/Lg set and the Lk/Lg × Lk set ( P ≪ 0.05). The resistances of Lg and Lg × Lk to bark stripping was stronger than Lk. This result was similar to those of previous studies on gray-sided voles and mountain hares in Hokkaido.

Damage caused by sika deer (Cervus nippon yesoensis) is a serious problem in commercial and environmental (non-harvested) forests in Hokkaido, northern Japan. Cafeteria tests in forests may be useful for evaluating the efficacy of chemical deterrents against bark stripping by deer. To develop a method for forest cafeteria tests in the continuous snow cover period, two experiments were carried out. In the experiments, logs were produced from tree trunks, and used as carriers of chemical deterrents. Carriers were installed in forests and fed to deer. The first experiment was to find suitable sites and installation methods for carriers. Criteria for the local suitability and the installation methods were as follows: a) Sites where deer are active should be selected; b) Carriers should be installed along actively used deer trails; c) Installation sites of carriers should be changed in response to deer movement; d) Carriers should be produced from tree species that deer naturally prefer; and e) Each carrier should be partially buried in the snow. The second experiment evaluated the feasibility of a cafeteria test method based on the results of the first experiment. The method was used for 13 sets of the cafeteria test, in which the deterrent effectiveness of 5 chemicals (wood tar, rosin, wood vinegar, and 2 pyroligneous liquors) was examined. We obtained results from all the sets. The chemicals tested did not deter bark stripping by deer. Nevertheless, the method used in the present study was practical for the cafeteria tests.