We have tried to facilitate nesting of medium-sized birds of prey by placing artificial nests on young conifers without thick branches that could support their nests. A pair of the northern goshawk Accipiter gentilis and a pair of the black kite Milvus migrans nested on the artificial nests. The goshawks raised two fledglings successfully. The black kites abandoned the nest during brooding possibly due to the disturbance by people searching for edible wild plants. The goshawks used the artificial nest although their natural nest in the previous year was nearby. The artificial nest used by the black kites was located in the area where the nesting of medium-sized birds of prey, including the black kite, had not previously been observed. The results indicate that it is possible to artificially facilitate nesting of medium-sized birds of prey even on the conifers that have not developed thick branches, which may be simply because of the age or the delay of thinning. The application of this technique could render the forests without trees suitable for nesting, possibly leading to the expansion of their habitat.

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Contamination by different clones in a cutting garden is a serious problem for seedling quality. Clonal analysis of trees in a cutting garden can be performed using highly polymorphic microsatellite markers. However, clonal analysis of every tree is laborious and expensive. To establish an effective method for clonal analysis of trees in the Shakain cutting gardens of Kumamoto Prefecture, we conducted microsatellite analysis using bulked DNA. We bulked Shakain needle samples and those of other cultivars at proportions of 4:1 and 9:1. Then, we extracted DNA from the bulked samples and used it as a template for microsatellite analysis. We accurately identified the contaminated bulked samples by detecting peaks from other cultivars. We applied this method to two Syakain cutting gardens: cutting garden A consisting of 387 trees and cutting garden B consisting of 1,007 trees. Finally, we identified three contaminated trees by analyzing 103 samples (21.1%) in cutting garden A and 353 samples (35.1%) in cutting garden B, respectively. Thus, microsatellite analysis using bulked DNA is an effective method for clonal analysis of trees in a Shakain cutting garden of Cryptomeria japonica.

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Logs artificially inoculated with Amylostereum laevigatum (a fungal symbiont of wood wasps) and control logs were placed in a field for oviposition by wood wasps in spring 2013. Wood wasp adults emerged from the logs in spring and summer 2014. All of the emerging wood wasps were Xeris spectrum adults, and all of them emerged from logs inoculated with A. laevigatum. Adult X. spectrum females thus preferred to oviposit in inoculated logs. More X. spectrum adults emerged from logs with fruiting bodies of A. laevigatum, and the reproductive success of X. spectrum was higher in logs with fruiting bodies than in those without them. This field study clearly revealed that X. spectrum preferred to oviposit on inoculated logs of A. laevigatum and emerged only from them.

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For the effective selection of pine wilt disease-resistant Pinus thunbergii trees, we implemented three strong inoculation tests of the seedlings with pine wood nematodes (PWNs). In the first test, we studied the environmental conditions associated with increased mortality after inoculation. The inoculation was performed in a greenhouse under high temperature and the pot-grown seedlings were subjected to moisture stress. Under these conditions, the survival rate following inoculation with 10,000 Shimabara, a highly virulent PWN isolate, was approximately 3%. In the second test, we attempted to increase the mortality by increasing the number of PWNs in an inoculation. When we inoculated seedlings with 10,000 or 20,000 Shimabara, the survival rate following inoculation with 20,000 PWNs was half than that with 10,000 PWNs. The third test examined the association between the increased resistance of undamaged population and their inoculation history. We repeatedly inoculated undamaged seedlings with PWN in subsequent years and selected the undamaged seedlings. The selected populations were inoculated with 20,000 Ka-4, which is another highly virulent PWN isolate. Withering of seedlings with a history of many inoculations progressed slowly, and their survival rates increased. The withering process was in line with the previous reports on resistant P. thunbergii varieties. We concluded that this method is effective for the selection of resistant P. thunbergii.

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The purpose of this study was to clarify the changes in the concentration and amount of radiocesium in decomposing litters in Satoyama consisting of deciduous broad-leaved forest where radionuclides released from the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) were deposited. The concentration and amount of radiocesium in decomposing litters before and after the FDNPP accident (March 2011) were compared. The concentration of radiocesium in leaf litter was 2.3-14.6 Bq/kg from March to November in 2009. The concentration of radiocesium in leaf litter significantly increased after the autumn of 2012. The amount of radiocesium in leaf litter increased despite a decrease in dry mass with decomposition relative to the beginning of the study period. It suggested that increases in the concentration and amount of radiocesium in decomposing litters might be attributed to the incorporation of radiocesium via microbial absorption in the soil surface, and concentrated with the weight loss.

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A large number of Pinus thunbergii seedlings are required for establishment in coastal areas after the tsunami disaster. Therefore, a reduction in the duration of seedling nursing period and year-round planting to equalise the amount of work are required. We compared the stem growth of current-year containerised seedlings (CCS) and 2-year-old conventional bare-root seedlings (TBS), and planted the containerised seedlings every 2 months except during midwinter (January). There was no significant difference between the stem length of CCS and TBS after one growing season. For CCS planted during March, stem longitudinal growth was smaller than that of TBS; however, for those planted during November, no significant difference was noted. Stem radial growth of CCS was higher than that of TBS. Seedling percentage survival rates of CCS after one growing season was high (>98.4%), regardless of the planted month. In conclusion, usage of current-year seedlings and year-round planting of containerised seedlings could be possible in the regions with environmental conditions similar to the study area.

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Thujopsis dolabrata var. hondae (Cupressaceae) is a Japanese endemic tree species that often reproduces vegetatively by layering. The population clonal structure has been examined previously using isozyme markers. However, accurate identification of genets is difficult using isozyme markers because of a low genetic diversity. In the present study, for identification of clones among 359 saplings in a natural forest of T. dolabrata var. hondae, we used multiplex PCR with six highly polymorphic expressed sequence tag-simple sequence repeat (EST-SSR) markers previously developed for Thujopsis. Forty-five genets were identified using three or over of the EST-SSR loci. The maximum and mean number of trunks per genet in the study plot was 92 and 8.0, respectively. These results indicated that clonal saplings in a natural forest of T. dolabrata var. hondae were readily and accurately identified using a single multiplex PCR assay with the six EST-SSR markers.

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