Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

We present the largest freely available EcoPlate dataset for Japan, comprising data collected from a network of 33 natural forest sites (77 plots) in regions of East Asia ranging from cool temperate to subtropical. EcoPlate is a 96-well microplate that contains three repeated sets of 31 response wells with different sole carbon substrates. The utilization of each carbon substrate by the microbial community is quantified by the color density of the well during incubation. EcoPlate can provide a multifunctional index of a soil microbial community. Soil properties (water content, carbon [C] and nitrogen [N] contents, the C/N ratio, and pH) that are essential for interpreting the EcoPlate results were also measured. The network is part of the Forest and Grassland Survey of the Monitoring Sites 1000 Project established by the Ministry of the Environment. Using a standardized protocol, soil was sampled between September and December 2020. A preliminary principal component analysis was performed on the temporal integration of color density using 31 substrates. For the temporal integration, we calculated the cumulative amount of color development by integrating the color density development curve. PC1 contributed 55.6% and is thought to represent the magnitude of the overall absorbance of all substrates. The model of environmental factors including elevation and the model of soil properties, including water content and pH, were selected as the best-fit models for variation in PC1. EcoPlate data enable the meta-analysis of comparative studies among forest types and testing community ecology and ecosystem function hypotheses at broad spatial scales. The complete data set for this abstract published in the Data Paper section of the journal is available in electronic format in MetaCat in JaLTER at http://db.cger.nies.go.jp/JaLTER/metacat/metacat/ERDP-2022-01.1/jalter-en.

DOI： 10.1111/1440-1703.12293

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BACKGROUND AND AIMS: Interspecific difference in pollinators (pollinator isolation) is important for reproductive isolation in flowering plants. Species-specific pollination by fungus gnats has been discovered in several plant taxa, suggesting that they can contribute to reproductive isolation. Nevertheless, their contribution has not been studied in detail, partly because they are too small for field observations during flower visitation. To quantify their flower visitation, we used the genus Arisaema (Araceae) because the pitcher-like spathe of Arisaema can trap all floral visitors. METHODS: We evaluated floral visitor assemblage in an altitudinal gradient including five Arisaema species. We also examined interspecific differences in altitudinal distribution (geographic isolation) and flowering phenology (phenological isolation). To exclude the effect of interspecific differences in altitudinal distribution on floral visitor assemblage, we established 10 experimental plots including the five Arisaema species on high- and low-altitude areas and collected floral visitors. We also collected floral visitors in three additional sites. Finally, we estimated the strength and contribution of these three reproductive barriers using the unified formula for reproductive isolation. KEY RESULTS: Each Arisaema species selectively attracted different fungus gnats in the altitudinal gradient, experimental plots, and additional sites. Altitudinal distribution and flowering phenology differed among the five Arisaema species, whereas the strength of geographic and phenological isolations were distinctly weaker than those in pollinator isolation. Nevertheless, the absolute contribution of pollinator isolation to total reproductive isolation was weaker than geographic and phenological isolations, because pollinator isolation functions after the two early-acting barriers in plant life history. CONCLUSIONS: Our results suggest that selective pollination by fungus gnats potentially contributes to reproductive isolation. Since geographic and phenological isolations can be disrupted by habitat disturbance and interannual climate change, the strong and stable pollinator isolation might compensate for the weakened early-acting barriers as an alternative reproductive isolation among the five Arisaema species.

DOI： 10.1093/aob/mcaa204

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY  

Global climate change increases uncertainty in sustained functioning of forest ecosystems. Forest canopies are a key link between terrestrial ecosystems, the atmosphere, and climate. Here, we introduce research presented at the 66th meeting of the Ecological Society of Japan in the symposium "Structure and function of forest canopies under climate change." Old-growth forest carbon stores are the largest and may be the most vulnerable to climate change as the balance between sequestration and emission could easily be tipped. Detailed structural analysis of individual large, old trees shows they are allocating wood to the trunk and crown in patterns that cannot be deduced from ground, thus can be used to more accurately quantify total forest carbon and sequestration. Slowly migrating species sensitive to novel climatic conditions will have to acclimate at the individual level. Accounting for physiological responses of trees to climate change will improve predictions of future species distributions and subsequent functioning of forest ecosystems. Field experiments manipulating temperature and precipitation show how trees compensate physiologically to mitigate for higher temperatures and drought. However, it is difficult to measure acclimation responses over long timeframes. Intraindividual trait variation is proposed as an indicator of acclimation potential of trees to future conditions and suggests that acclimation potential may vary among regional populations within a species. Integrating whole-tree structural data with physiological data offers a promising avenue for understanding how trees will respond to climatic shifts.

DOI： 10.1111/1440-1703.12127

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Publishing type：Research paper (scientific journal)   Publisher：Genetics Society of Japan  

DOI： 10.1266/ggs.95.51

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY  

Premise The genus Arisaema (Araceae) has rapidly diversified in Japan, and multiple species often coexist in the field. Although Japanese Arisaema species hybridize from artificial crossing, hybrid individuals are rare in mixed populations; suggesting the presence of effective pre-pollination barriers. We examined the following reproductive barriers between A. sikokianum and A. tosaense: habitat, phenology, and pollinator isolations. Methods Habitat isolation was examined by interspecific comparisons of microhabitat conditions at a mixed site and of altitude at the sampling site of herbarium specimens. Phenological isolation was evaluated by comparing seasonal transition in apparent spathe condition and frequency of insect visitation. Pollinator isolation was examined by comparing floral visitor assemblages between the two Arisaema species. To avoid overestimation of pollinator isolation due to seasonal changes in insect assemblages, we also compared visitor assemblages between natural and late-flowering A. sikokianum, where the latter was experimentally introduced and blooming with a natural A. tosaense population. Results Microhabitat conditions and sampling elevations of herbarium specimens overlapped between the two Arisaema species. At the population level, A. sikokianum and A. tosaense flowered for 39 and 52 days, respectively, with 13 days overlap. Insect visitation in A. sikokianum decreased before the seasonal overlap. Floral visitor assemblages differed between the two Arisaema species, while the difference between natural and late-flowering A. sikokianum was less distinct. Conclusions Phenological and pollinator isolation contribute to reproductive isolation between the two Arisaema species and should enable the two species to coexist in this area.

DOI： 10.1002/ajb2.1389

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：GENETICS SOC JAPAN  

Commelina communis f. ciliata (Commelinaceae), a newly distinguished taxon, is an annual andromonoecious herb exhibiting a mixed mating system, the details of which remain unclear. We developed microsatellite markers for use in exploring the evolution of andromonoecy and mixed mating in the species. Fifteen micro satellite loci were developed using next-generation sequencing. The primer sets were used to evaluate 65 C. communis f. ciliata individuals from three populations in Japan; we found 1-13 alleles per locus and the expected heterozygosity ranged from 0.00 to 0.76. The markers are potentially useful to examine intra- and inter-species genetic structure and the mixed mating strategy of Commelina species via paternity analysis.

DOI： 10.1266/ggs.18-00058

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Language：Japanese   Publisher：The Ecological Society of Japan  

Canopy biology is the natural science that aimed at understanding of the biodiversity, biological processes, and ecological functions of forest canopies. Canopies determine the structural and energetic properties of forest ecosystems. Since the 1980s, canopy biology has progressed rapidly through the development of methods for accessing treetops. The rope climbing techniques used widely in canopy studies have developed from diverse procedures that allow human access to the top layers of forest vegetation. In comparison with other access hardware, e.g., cranes and gantries, rope assemblies have advantages in terms of user mobility, repeated access, and cost. The availability and safety of tree climbing techniques have improved with recent developments in mountain climbing gear and methodologies for their use. In this review, we use candidate studies to introduce the advantages, prospects and challenges of climbing techniques for tree canopy studies. Tree climbing allows excellent access to treetops in all types of forests, across all geographical locations. We expect further progress through combinations of rope climbing and other access methodologies. In the interests of safety and effectiveness, a platform should be developed for the distribution of relevant information to prospective tree climbing researchers and those who may wish to use the procedures for other activities, such as arboriculture.

DOI： 10.18960/seitai.68.2_125

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Other Link： https://agriknowledge.affrc.go.jp/RN/2010922617

Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER JAPAN KK  

Estimating the timing of flower bud formation in plants is essential to identify environmental factors that regulate floral transition. The presence of winter dormancy between the initiation of flowers and anthesis, characteristic of most trees in the temperate forests, hampers accurate estimation of the timing of floral transition. To overcome this difficulty, expression levels of flowering-time genes could be used as indicators of the timing of floral transition. Here, we evaluated the usefulness of molecular markers in estimating the timing of floral transition in Fagus crenata, a deciduous tree that shows intermittent and synchronized flowering at the population level. We selected FLOWERING LOCUS T (FT) as a candidate molecular marker and quantified the expression levels of its ortholog in F. crenata (FcFT). Subsequently, we analyzed the relationship between morphogenetic changes that occur between the vegetative state of the buds and the initiation of floral organs, and compared the FcFT expression levels in reproductive and vegetative buds, collected from spring to autumn. FcFT expression in leaves peaked at least two weeks before the morphological changes associated with flowering were visible in the buds in late July. FcFT expression levels were significantly higher in the reproductive buds than in the vegetative buds in July. These results suggest that the FcFT expression in July is a reliable indicator of the timing and occurrence of floral transition. This study highlights the utility of molecular tools in unraveling reproductive dynamics in plants, in combination with ecological and physiological approaches.

DOI： 10.1007/s11284-017-1462-3

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：TAYLOR & FRANCIS LTD  

The seedling stage is critical in the life cycle of trees, and performance is controlled by both abiotic and biotic factors, which are spatially heterogeneous. We investigated the relationships between the seedling survival or growth of Fagus crenata and seven potentially influencing factors (culm density of dwarf bamboo, slope angle, topographic convexity, distance from the nearest conspecific adult, and local density of F. crenata seedlings, and seedling size and age), under consideration of the changes in direction and strength of the microtopographic effects across space. In 2011, we identified all F. crenata seedlings (maximum stem length <50cm) within a 90x30-m plot in a cool-temperate forest in western Japan and then recorded their survival and growth of stem length in 2012. The best model based on Akaike's information criterion indicated that the size, age, and distance had positive effects on the survival while slope and convexity had negative effects, and that the strength of the negative effect of convexity varied spatially even within our plot. Meanwhile, the size and culm density had positive and negative effects on the growth, respectively. These results suggest that F. crenata seedlings have more chance to survive at the site on a gentle slope with planar or relatively concave undulations, where the conspecific adults stood apart, and that the seedlings show higher growth rate at the sites without dense dwarf bamboo. Furthermore, we demonstrate that the spatially nonstationary effect of microtopography controls the spatial pattern of seedling survival.

DOI： 10.1080/13416979.2017.1354749

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Language：English   Publisher：TAYLOR & FRANCIS LTD  

DOI： 10.1080/13416979.2017.1362154

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

Seedling genotype is one of the major factors affecting seedling survival when the rate of damage by natural enemies depends on a host genotype. However, to our knowledge, no previous study has examined the mortality of seedlings adjacent to conspecific adults, considering intraspecific variation in seedling genotypes. On the basis of the assumption that natural enemies adapt to adult trees having a unique genotype, we tested the hypothesis that seedling survival decreases when they are more closely genetically related to neighboring adults, by measuring the mortality rate of seedlings of Fagus crenata growing in a cool-temperate forest in Japan. We estimated the genetic relatedness of seedlings (2 and 6 years old) to the neighboring adult F. crenata using microsatellite analysis and measured seedling survival. We determined that there was a non-significant negative correlation between seedling survival and genetic relatedness in the 2-year-old seedling cohort, and a non-significant but positive correlation in the 6-year-old seedlings. Our results call for further studies on the potential relationship between seedling survival and genetic relatedness to neighboring adults.

DOI： 10.1007/s11258-016-0591-z

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：TAYLOR & FRANCIS LTD  

Dendrochronological approaches enable us to understand forest stand dynamics by estimation of disturbance history and age structure. The present study was conducted in an old-growth beech forest in a forest reserve in western Japan. Increment cores were taken for tree ring analysis from all canopy trees in a 50 m x 130 m study plot. Radial growth release criteria were developed to identify significant growth releases in each tree ring series and to characterize the disturbance history of the study site. The age structure of the forest was indicative of continuous establishment by Fagus crenata and simultaneous establishment by Magnolia obovata. A variety of low-intensity disturbances were identified in each decade, especially after the 1900s, but the occurrence of high-intensity catastrophic disturbance was rare, and likely played an important role in maintaining species diversity in the existing forest canopy. The results also suggest that F. crenata regenerates gradually before and after both large- and small-scale disturbances, whereas M. obovata and Betula grossa regenerate only after large-scale catastrophic disturbances.

DOI： 10.1007/s10310-015-0514-1

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Ecological Society of Japan  

To manage the expansion of bamboo forests efficiently, it is necessary to predict where expansion is likely. However, predicting bamboo distribution using statistical models is challenging due to biased distributions, heterogeneous invasion histories, and strong neighbor effects. Furthermore, clonal and invasive species such as bamboo show a non-linear response to environmental factors. Here, we construct a spatial model to predict locations of high penetration probability after controlling for these problems, using data for bamboo distribution in Toyooka, Hyogo Prefecture, Japan. First, we used MaxEnt to reveal the full range of possible bamboo survival and to control for the effects of clonal growth. Second, we constructed a predictive model of invasion using environmental factors. The first model showed that distance from the source patch strongly affected expansion and that constraints from environmental factors were not significant. The final model explained about 70% of actual expansion. Scenario analyses showed that bamboo expansion is best controlled by removing smaller patches. Based on our results, we discuss issues in bamboo forest management and planning.

DOI： 10.18960/hozen.20.1_3

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

The role of resource availability in determining the incidence of masting has been widely studied, but how floral transition and initiation are regulated by the resource level is unclear. We tested the hypothesis that floral transition is stimulated by high resource availabiltiy in Fagus crenata based on a new technique, the expression analyses of flowering genes. We isolated F. crenata orthologues of FLOWERING LOCUS T, LEAFY and APETALA1, and confirmed their functions using transgenic Arabidopsis thaliana. We monitored the gene expression levels for 5 years and detected a cycle of on and off years, which was correlated with fluctuations of the shoot-nitrogen concentration. Nitrogen fertilisation resulted in the significantly higher expression of flowering genes than the control, where all of the fertilised trees flowered, whereas the control did not. Our findings identified nitrogen as a key regulator of mast flowering, thereby providing new empirical evidence to support the resource budget model.

DOI： 10.1111/ele.12338

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER JAPAN KK  

Several proximate factors of masting have been provided. Here, I focus on the role of internal factors, especially the relationship between internal carbon resources and modular structures in trees. I summarize various studies of carbon resource allocation for reproduction during masting events in terms of the proximate factors of masting and discuss the modular structure in which trees accumulate and consume carbon resources as well as the timing when internal carbon resources affect masting since trees have complex resource dynamics among organs. The resource budget model, which provides a simple mechanistic explanation of the masting mechanism, is supported by various study lines. This model assumes decreasing levels of stored photosynthate after flowering and fruiting. According to several studies, however, carbon reserves do not decrease after fruiting in species in which the modules autonomously allocate current photosynthate for fruiting. In addition, it is important to elucidate when carbon resources affect masting events because during their long developmental processes, trees pass through various stages until they produce maturing fruits to create successful masting events. To explore the mechanisms of masting in future studies, it would be important to figure out how and when candidate factors (including nutrients other than carbon) may influence the entire reproduction process, for example, using field manipulation experiments.

DOI： 10.1007/s11284-011-0892-6

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Language：Japanese   Publisher：日本生態学会暫定事務局  

ササ類は開花・結実の豊凶がきわめて明瞭であり、加えて生涯で一度のみ繁殖する一回繁殖型植物と考えられてきた。一方、ササ類は個体群の遺伝構造の把握が困難であったため、これまで一回繁殖性について検証されることはなかった。しかしササ類の特異的な繁殖特性を解明するにはまず一回繁殖性の検証が不可欠である。そこで、オモエザサ個体群において遺伝構造を調べると共に、4年間の開花パターンの調査を行い、一回繁殖性の検証を行った。その結果、開花稈は全て同一ジェネットに属し、ジェネットの占有面積は3ha以上に及んだ。しかし、同一ジェネット内の稈が全て開花したのではなく、大別すると、全ての稈が開花していない範囲、開花稈と非開花稈が混在している範囲、全ての稈が開花している範囲がそれぞれ、同一ジェネット内に同時に存在した。全ての稈が開花した範囲のうち、開花後に全ての地上部が枯死した範囲もあったが、翌年以降も稈が生残する範囲もあった。開花後に地上部が枯死した範囲の地下茎からは、翌年以降に新しい稈や花序が再生する現象がみられた。開花が起こる範囲は年毎に変化したが、同一ジェネットに属していても4年間でまだ一度も開花していない範囲も存在した。また、ラメット間の生理的統合を調べるため、炭素安定同位体(<sup>13</sup>C)を用いてトレース実験を行った結果、非開花稈から地下茎で繋がった開花稈へ<sup>13</sup>Cが転流していた。これらのことから、研究対象としたオモエザサは一斉に開花はするものの、必ずしも一回繁殖型の生活史を有していないことが分かった。

DOI： 10.18960/seitai.60.1_73

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER JAPAN KK  

Airborne pollen of Cryptomeria japonica causes severe pollinosis, and the number of people suffering from pollinosis has increased rapidly during recent decades. Male flower production in C. japonica shows annual variability; thus, predicting male flower production for the following spring could be a countermeasure against pollinosis. We analyzed factors that explain fluctuations in male flower production of C. japonica according to parameters reflecting internal resource dynamics based on field observations. In addition, we carried out experiments to regulate available resource levels using artificial shading to test the effect of internal resource levels on the number of male flowers produced. We found that temperature and precipitation in the previous summer and a relative increase in male flower production in the previous year were negatively related, whereas sunshine duration in the previous summer and diameter at breast height were positively related to the current year increase in male flower production. The number of male flowers was significantly reduced by the shading treatment and was positively correlated with the amount of total non-structural carbohydrates in the root. These results suggest that understanding the parameters controlling internal resource levels could lead to more accurate predictions of male flower production.

DOI： 10.1007/s10310-009-0148-2

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER TOKYO  

Dwarf bamboos in the genus Sasa are believed to be long-lived, synchronously flowering, and monocarpic plants. However, the monocarpy of dwarf bamboo has not been confirmed, because whether all ramets within one genet flower at the same time cannot be determined without differentiating the genetic structure among ramets. This study aims to evaluate the reproductive traits of Sasa pubiculmis by verifying the monocarpy and physiological integration between flowering ramets and non-flowering ramets during a 4-year flowering period. One genotypically identified genet, which covered an area of approximately 3 ha, had both flowering and non-flowering patches of ramets during the 4-year flowering period (2004-2007). A fraction of the flowering genet remained non-flowering during the 4 years of observation, and did not die after mass flowering. Flowering ramets were physically connected to non-flowering ramets via rhizomes, and assimilated (13)C was allocated from non-flowering ramets to flowering ramets. Consequently, we clarified that this dwarf bamboo potentially has polycarpic reproductive traits rather than monocarpic, and a genet can keep rhizomes and non-flowering patches alive to sustain the organism after mass flowering.

DOI： 10.1007/s10265-009-0241-9

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

Sasa senanensis is a dwarf bamboo species distributed on the floors of cool temperate forests in Japan and adjacent regions. We isolated eight polymorphic microsatellite loci from this species. The number of alleles ranged from two to eight and the observed heterozygosity per locus from 0.13 to 0.74. Seven of the eight loci were also polymorphic in Sasa nipponica. Most of these markers were successfully amplified in other dwarf bamboo species. These markers will be useful for investigating clonal structure and population genetics in some dwarf bamboo species.

DOI： 10.1007/s10592-008-9575-4

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Language：Japanese   Publisher：THE JAPANESE FORESTRY SOCIETY  

DOI： 10.11519/jfsc.119.0.40.0

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BLACKWELL PUBLISHING  

DOI： 10.1111/j.1442-1984.2007.00176.x

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：OXFORD UNIV PRESS  

An analysis is presented of three possible pathways of reproductive allocation, namely, allocation of resources to reproductive organs from reproductive shoots, from non-reproductive shoots and from the main trunk. These pathways were examined by comparing the amount of storage starch in reproductive shoots, non-reproductive shoots and the main trunk in Styrax obassia, a typical masting tree species, during a year of little flowering (1999) and in a mass-flowering year (2000), In addition, we measured rates of light-saturated photosynthesis in leaves of reproductive and non-reproductive shoots to examine the contribution of photosynthetic production to reproductive costs. In both the main trunk and non-reproductive shoots the pattern of seasonal variation in the amount of starch did not differ between 1999 and 2000. However, in the mass-flowering year, the amount of starch in the reproductive shoots was less than that in non-reproductive shoots during the growing season. Thus, reproductive shoots bore most of the cost of reproduction, although non-reproductive shoots and the main trunk also bore some of the cost. Mass-based rates of light-saturated photosynthesis of the leaves of reproductive shoots were significantly higher than those of non-reproductive shoots during both the flowering and the fruiting period. However, leaves of reproductive shoots had a significantly smaller area, a lower mass per area, and lower concentrations of nitrogen than leaves of non-reproductive shoots, although the number of leaves did not differ between the two types of shoots. Therefore, the amount of photosynthate per shoot was significantly lower in reproductive shoots than in non-reproductive shoots. These results suggest that the cost of reproduction depends predominantly on storage starch in reproductive shoots, although it is still unclear how much photosynthate is allocated to reproductive organs from non-reproductive shoots. (C) 2002 Annals of Botany Company.

DOI： 10.1093/aob/mcf107

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Language：Japanese   Publisher：奈良県森林技術センター  

ブラジルパラナ州北部、南部およびウルグアイ産のユーカリ材の強度試験および耐朽性試験を行った。ユーカリ材の密度は0.44～1.05g/cm2と分布範囲が大きく、産地の違いによる密度の違いが認められた。ユーカリ材のヤング係数、曲げ強さ、衝撃曲げ吸収エネルギーおよび収縮率は密度の増加とともに増大した。パラナ州北部産のユーカリ材は、密度が0.93g/cm2と最も高く、ヤング係数が22.2kN/mm2、曲げ強さが155N/mm2と高い強度性能を示した。一般的な木材と比較すると、密度との関係において曲げ強さは同等であり、ヤング係数は高い傾向を示したが、逆に衝撃曲げ吸収エネルギーはやや低い傾向を示した。ユーカリ材のオオウズラタケおよびカワラタケに対する質量減少率は3.1～7.6%であり、中程度の耐朽性を示した。

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Language：Japanese   Publisher：奈良県森林技術センター  

2種類の木材保存剤(ACQ、AZP)で処理したラミナを、2種類の接着剤(レゾルシノール系樹脂接着剤、水性高分子イソシアネート系樹脂接着剤)で接着して作製した、5プライのスギ集成材の屋外ばくろ試験を実施している。ばくろ5年後のせん断試験の結果、ACQ処理-レゾルシノール系樹脂接着剤の組み合わせで、せん断強度が低下する傾向が認められた。他の組合わせおよび木材保存剤で処理しなかったスギ集成材では、その傾向が観察されなかったことから、ACQの影響によるものと推測された。木材保護塗料は、木材の表面劣化を抑止するには効果的であった。しかし、木材保護塗料を2年ごとに塗布した場合であっても、ACQ処理-レゾルシノール系樹脂接着剤の組み合わせでは、接着はく離が発生するなど、接着強度の低下が観察された。ばくろ3年後までは、いずれの集成材でもほぼ100%であった木部破断率は、ばくろ5年後において低下した。しかし、木部破断率とせん断強度との間に相関は認められなかった。深木部破断率は、ACQ処理-レゾルシノール系樹脂接着剤の組み合わせでより低い値を示し、この組み合わせでは接着層界面近辺での破壊発生が増加することが示唆された。

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Language：Japanese   Publisher：奈良県森林技術センター  

竹林の拡大防止のため、薬剤を用いた竹の効率的な枯殺方法を検討した。竹林の皆伐のみを行った試験区と、皆伐後に切株へ薬剤を注入した試験区を比較した結果、皆伐後に切株へ薬剤を注入した試験区では、翌春の新稈発生本数が少なかった。また、7月下旬に処理を行った後約2ヶ月経過後までに、皆伐のみを行った試験区において皆伐後に切株へ薬剤の注入を行った試験区に比べて多数のササ状に矮性化した再生稈が認められた。これらのことから、皆伐後に切株へ薬剤の注入を行った試験区では、皆伐のみを行った試験区と比較して当年および翌年の新稈の発生が抑制されていると考えられる。

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Language：Japanese   Publisher：奈良県森林技術センター  

ラミナを木材保存剤で注入処理した集成材の接着耐久性評価として5種類(ACQ、AAC、NCU、NZN、CUAZ)の木材保存剤で処理したラミナと2種類のレゾルシノール樹脂系接着剤を組み合わせて作製した集成材の5回繰り返し煮沸はくり試験および減圧加圧試験を実施した。その結果、大部分の木材保存剤で処理したラミナを使用した集成材のはく離率は、ほぼ良好な値を示した。しかし、木材保存剤の種類と接着剤の種類によってはく離率に差があった。また、無処理の集成材と比較すると、保存剤で処理したラミナを使用した集成材には接着性能の低下が認められた。2種類のレゾルシノール樹脂系接着剤の間で接着性能に差が見られ、一方の接着剤ではNZNおよびACQによって注入処理したラミナを使用した集成材のはくり率の平均値が高く、NZNは5%を超えた。また、AACで処理したラミナを使用した集成材のはくり率は、すべての条件において低かった。

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Language：Japanese   Publisher：奈良県森林技術センター  

スギ正角乾燥材および水性高分子-イソシアネート系接着剤を使用して製造された、2種類の接着重ね梁の接着性能を、同一産地のスギ材と同じ接着剤とを使用して製造された集成材の接着性能とともに調べた。浸せきはく離試験、煮沸はく離試験および減圧加圧試験の結果、正角材を2本使用した接着重ね梁のはく離率が最も高かった。次に、正角材2本と一方の外層にラミナを接着した接着重ね梁のはく離率が高かった。それらと比較して、集成材のはく離率はいずれの試験でも低く、ほとんどの試験体が構造用集成材のJASで規定されている接着性能を満たしていた。2種類の接着重ね梁のせん断強度の間に、差は認められなかった。接着重ね梁のせん断強度と、集成材のせん断強度との間には差が認められた。

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Language：Japanese   Publisher：奈良県森林技術センター  

防腐処理を施したラミナを接着して製造した集成材の接着耐候性を、短期間で評価することを目的とした促進劣化試験(煮沸はくり試験、減圧加圧試験、ブロックせん断試験片の屋外ばくろ試験、ブロックせん断試験片の減圧加圧試験)を行った。その結果、銅・アルキルアンモニウム化合物系防腐薬剤(ACQ)処理集成材は、プロペタンホス・アゾール化合物系防腐薬剤(AZP)処理集成材および無処理集成材と比較して接着性能が劣っていた。今後、各種の促進劣化試験のうち、どの処理が最も接着耐候性の予測に適しているかについて、集成材の屋外ばくろ試験の結果と照らし合わせ、解析することが必要である。

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Language：Japanese   Publisher：奈良県森林技術センター  

集成材の接着耐候性を評価するため、銅・アルキルアンモニウム化合物系、ならびにプロペタンホス・アゾール化合物系防腐薬剤を加圧注入したスギラミナおよび無処理のスギラミナを接着して集成材を作製し、さらに木材保護塗料を塗布して、屋外ばくろ試験を行った。試験開始から3年経過後、保護塗料を塗布した集成材では、集成材側面に出現するはくり率の増加が抑制されていた。また、JASに準じたブロックせん断試験の結果、薬剤処理集成材のせん断強さが薬剤無処理集成材のせん断強さと比較して低くなる傾向がみられた。また、屋外ばくろ試験に供する前の集成材と比較した場合、保護塗料を塗布しなかった集成材において、せん断強さが若干低下していた。

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Language：Japanese   Publisher：奈良県森林技術センター  

奈良県産スギ材の構造用製材品への用途拡大を目的として、上北山村産のスギ材から得られた正角材を使用した接着重ね梁の曲げ試験を行って、以下の結果を得た。接着重ね梁は、高周波・蒸気複合乾燥したスギ正角材を2層重ねに接着したもの、およびこれに厚さ30mmのスギ材ラミナ1枚を接着し3層としたものを作製した。接着重ね梁の曲げ強さは、針葉樹の構造用製材の日本農林規格におけるスギ材の甲種構造用製材1級の基準曲げ強度をすべての試験体で上回っていた。しかし、それらは機械等級区分製材の基準曲げ強度を試験体18体のうち2つの試験体で下回った。2層接着重ね梁と3層接着重ね梁との比較では、曲げヤング係数は同等であったが、曲げ強さは後者のほうが高くなった。荷重とたわみの関係では、荷重が比例限度を越えると破壊に至る場合が多く認められた。

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Event date： 2022.3

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Dendro-ecological analysis is needed to understand stand dynamics of forests by estimating the disturbance history and age structure. The analysis was conducted in the old-growth beech forest of Wakasugi forest reserve (N35&rsquo;14&rsquo;, E135&rsquo;23&rsquo;), southwestern Japan. Increment cores were taken from all the tree individuals with dbh of more than 10cm, for tree ring analysis in the plots of 50m x 130m. For the disturbance history analysis, boundary-line release criteria were adopted to identify significant growth releases in each tree ring series, which are likely to be caused by disturbances. As results, age structure suggested continuous establishment by Fagus crenata and simultaneous establishment by Mognolia obovata. Disturbance history analysis showed that in this beech forest several disturbance events happened for 180 years. We are comparing the result with historical materials and discussing relationships between disturbance history and establishment of tree.

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Fagus crenata produce intermittently large numbers of seeds or flowers, not annual reproduction. Several hypotheses have been developed to explain the mechanism of intermittent reproduction; i.e. internal resources, climate cues. These proximate factors assume that the plant sets flowers as a result of that these factors induce differentiation of floral meristem as a starting signal. However, there are no direct evidences about whether these factors function as a signal of floral initiation, because it cannot be detected when the first switch of flowering on. In order to explore these factors on floral initiation, we quantified expression level of flower identity gene; LEAFY homolog (FcLFY) as well as process of flower bud differentiation using mature F. crenata. We measured seasonal pattern of FcLFY expression in bud using real-time quantitative PCR. In addition, we observed the relationship between FcLFY expression in bud and process of flower bud differentiation. We also analyzed relationship between FcLFY expression and internal resources. This approach could allow us to evaluate which proximate factor works as a signal of floral initiation in F. crenata.

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