We captured adult Japanese pine sawyer, Monochamus alternatus, after aerial application of microcapsules containing fenitrothion (MEP-MC) using live traps with chemical attractants in 10 Japanese black pine stands in Sakurajima. MEP was detected from the adults captured in the stands 39, 51, and 33 days after aerial application of MEP-MC in 2004, 2005, and 2006, respectively. Adults contaminated with MEP were also captured in unsprayed pine stands 4∼5 km away from the MEP-sprayed area 4 and 5 days after aerial application in 2004 and 2005, respectively. Based on the data of the capture of adults and detection of MEP from the adults captured in MEP-sprayed and unsprayed pine stands, we estimated the mortality of the adults due to MEP-MC application in 2005 and 2006 as 62 and 76%, respectively, in the sprayed stand, and 62 and 66%, respectively, in an adjacent pine stand to the MEP-sprayed area. These results suggest that aerial application of MEP-MC would be an effective measure to prevent the prevalence of pine wilt disease.

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Combining the data of current stand structures with past records regarding seed production, seedling dynamics and growth collected just before and after harvest cutting, we investigated the regeneration process of Fagus crenata over 30 years of natural regeneration practice, at the Hakkoda Research Site, northern Honshu, Japan. A large number of sound seeds were produced in 1976. The density of F. crenata seedlings in cutting years was 30,000 ha⁻¹ where clear cutting was carried out 1 year before the masting, while the density was 430,000 and 260,000 where shelterwood logging was carried out in the year after the masting and 2 years after the masting, respectively. The majority of regenerating trees were advanced seedlings that originated from the last masting before the cuttings. In 2007, ca 30 years after the cuttings, secondary forests with sufficiently high F. crenata density had been formed in the two shelterwood plots harvested after the masting, while the regeneration was relatively sparse in the clearcut plot harvested before the masting. Different forest floor treatments caused few differences in the densities of regenerating trees over the course of 30 years. These findings reveal that advanced regeneration played an important role in achieving the successful regeneration of F. crenata in this case.

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While the dwindling and aging population in the mountain villages of West Shikoku has caused a reduction of self-governing capabilities and resource management abandonment, and it is feared these settlements will disappear, the increasing resettlement of urban inhabitants, the growing interest in farming and forestry, and the promotion of relocation as one way to revitalize settlements are particularly noteworthy. Owning land and friendship with residents, that is, whether mountain villagers are inclined to offer land and accept newcomers are major factors in the consolidation of resettlement. In the present study we selected four settlement types—Vitality Sustainment, Dwindling Trend, Old-guard and Administrative dependence Expectation—from a questionnaire survey of West Shikoku and from an analysis of rural community statistics investigated the main cause of variations between settlements to gain an understanding of the characteristics of the acceptance of newcomers. The results show that the intent to accept newcomers is low in the four settlement types or are places where it is difficult to contemplate newcomers purchasing or leasing land. This shows the intent to accept newcomers varies with the intent to sustain a settlement, the status of resource management and outlook for the future, and it is considered that these have an impact on the survival of settlements.

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To examine factors affecting Hortonian overland flow generation in forested hillslopes, we measured overland flow at plots in Japanese cypress (Chamaecyparis obtusa), Japanese ceder (Cryptomeria japonica), and broadleaf forests of three study sites (Kochi, Mie, and Tokyo), which had different geology and climate. Overland flow occurred at all plots. Runoff ratios of overland flow were different among the three study sites rather than among forest species. By introducing overland flow index for each plot, we investigated relationships between the overland flow index and potential factors affecting overland flow generation. The index was not significantly associated with slope gradient and saturated hydraulic conductivity, whereas the index tended to be smaller as ground cover ratio increasing. This suggests that ground cover reduced rainfall impact to soil surface and thus contributed to preventing formation of structure crust, which inhibited infiltration and enhanced overland flow. The overland flow index increased as increases in silt and clay content in surface soils, implying that silt and clay content was an implicit factor influencing crust formation as a potential component of structure crust.

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We reviewed the research articles to understand the current findings and to suggest the future directions on relationship between biogeochemical cycling and forest practices in Japan. The studies on the effect of forest harvest on the biogeochemical cycling in forest has been mainly conducted using the manipulation experiments in forested basin, indicating that the tree cutting caused the significant nitrate leaching to stream due to the absence of nutrient uptake by trees. However, the unique processes in Japanese forest ecosystems has been also reported such as the role of nutrient uptake by understory vegetation after the tree cutting in northern Hokkaido, nitrate absorption in volcanic ash soil in northern Kanto region, and fluctuation of stream chemistry associated with basin hydrological processes during the last decades. In steeper slopes in southern Kinki region, it was suggested that the land slide after the forest practices has strong impact on the following hydrological processes and stream chemistry. The biogeochemical hot spots in the boundary of each ecosystem such as riparian buffer, nutrient spirals in stream channel, nutrient cycling in “SATOYAMA” region would be great concern for further understandings. It would be necessary to promote the studies on the parameterization in the ecosystem process model under the effect of forest practices with attention to their regional differences.

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Molecular markers are now available for assessing the phylogeography of a variety of organisms. Among scolytine beetles such as bark beetles, phylogeographical studies have advanced remarkably in recent years. Similar studies have also been carried out recently for several species of ambrosia beetles. We review and summarize recent studies pertaining to the phylogeography of bark beetles from three genera (Ips, Tomicus and Dendroctonus), as well as ambrosia beetles from the genus Xylosandrus. For bark beetles, we discuss host-specific factors that have affected the establishment of genetic structures and distribution patterns. For ambrosia beetles, we discuss the effects of geographic history on the distribution of beetle populations (i.e., haplotype diversity). In general, we observed a number of differences and similarities in the genetic structure of bark beetles versus ambrosia beetles. Using past as well as ongoing studies we describe the most critical factors that are likely to be responsible for the observed differences in the distribution of scolytine beetles.

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Scolytid and platypodid beetles are associated with fungi, including fungal species that belong to Ascomycota and Basidiomycota. Among the beetle-associated fungi, Ophiostomataceae and Ceratocystidiaceae are well studied because of their economic and ecological importance. In particular, the ambrosia fungi, which are mutualistic associates of ambrosia beetles, have been found to be phylogenetically heterogeneous and related to Ophiostomataceae or Ceratocystidiaceae. Several species in both the families are known to be close associates of bark beetles. Ambrosia beetle habits have evolved several times in the phylogeny of Scolytinae and Platypodinae, while their associated ambrosia fungi are thought to have evolved from many phylogenetically unrelated taxa. Consequently, diverse relationships from facultative to obligate mutualism have been developed between the beetles and the fungi.

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The coleopteran family Curculionidae is one of the most important vector and/or host insect groups for entomogenous nematodes in the world. The bark beetles are members of the subfamily Scolytinae and appear to be a very suitable host/vector group for the nematodes, i.e., more than 100 species of parasitic and/or phoretic nematodes have been described from this group. Contrastingly, only seven nominal species have been recorded from the ambrosia beetles and the rest of the Scolytinae and Platypodinae, which are closely related to the bark beetles. Thus far, there is no clear explanation for the differences in nematode diversity between the bark and the ambrosia beetles. The life cycle and habitat environmental conditions do not differ that much between these two beetle groups. However, some nematode groups, e.g., the genus Ruehmaphelenchus, have been isolated only from the ambrosia beetles, and are hypothesized to be specific to them. Most of the current studies on bark and ambrosia-beetle associated nematodes are descriptive. Understanding the stenotrophic relationships between ambrosia-beetles and their associated nematodes and the evolutionary implications of these interactions will require experimental studies and more extensive descriptive survey work in the future.

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Associations between bark- and ambrosia-beetles and mites include phoresy, parasitism, predation, commensalism, and mutualism. One of the main associations is phoresy, which is mite “hitch-hiking” for dispersal through other organisms. I suggest that most symbiosis between the beetles and mites evolved from phoresy. Since the associations are reported to exist in Mesostigmata, Prostigmata, Astigmata and Oribatida without genetic relationships, I conclude that association with the beetles evolved independently and multiple times in the order Acari. Predacious mites do not show food specificity to the beetles but they feed on insect eggs and larvae including bark and ambrosia beetles, nematodes and other small organisms. Negative impacts by mite predation and parasitoidism are negligible given that those mites are phoretic on the host beetles. Mutualism is not direct but indirect between the beetles and mites, involving fungi, nematodes and other mites. Therefore, I hypothesize that associations between them developed due to the use of the same habitat.

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We reviewed the ecological traits of bark and ambrosia beetles (Curculionidae: Scolytinae and Platypodinae), focusing on factors such as diets, mating systems, gallery systems, and sociality. Beetles were divided into two diet groups. One group consisted of bark beetles that bore into various plant parts to feed on the underlying tissues. The other group consisted of an ambrosia beetle that bores into wood to feed on symbiotic microorganisms cultivated on the gallery walls. Beetles used one of four possible mating systems: female-initiated monogyny, inbreeding polygyny, harem polygyny, and male-initiated monogyny. Reproductive characteristics observed also included haplodiploidy, pseudogamous parthenogenesis, and thelytoky. The gallery systems created by beetle groups generally reflected their respective diets and mating systems. Eusociality was observed in a beetle of Platypodinae, Austroplatypus incomperus, where the female adults formed the sterile caste. We also introduced the observation of altruism in the larvae of Platypus quercivorus. Finally, we discussed the importance of developing artificial rearing methods that allow researchers to directly observe the ecological traits of beetles as they feed in their gallery systems.

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A taxonomic history of Japanese bark and ambrosia beetles is given, and their scientific and common Japanese names are listed. In the list, five species were newly given Japanese common namea. It is thus clear that 302 species of Scolytidae and 18 species of Platypodidae have been recorded in Japan.

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