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Azuma WakanaGraduate School of Agricultural Science / Department of Bioresource ScienceAssistant Professor
Research activity information
■ Award- Mar. 2025 第72回日本生態学会大会, 第72回日本生態学会大会「いいね！」賞, 京都府の冷温帯林におけるカブトゴケ属（Lobaria）の景観規模での遺伝的多様性
- Mar. 2025 日本森林学会, 第136回 日本森林学会学生ポスター賞, ヤクスギ巨樹上の林冠土壌中の微生物群集の解明
- Mar. 2025 The Japan Wood Research Society, International Symposium on Wood Science and Technology 2025 Best Poster Award, Intra-individual vessel variation in the axial and radial direction of Para rubber tree (Hevea brasiliensis)
- Feb. 2025 神戸大学, 令和６年度自然科学系長賞
- Mar. 2024 一般社団法人 日本森林学会, 第135回日本森林学会学生ポスター賞, スギ集団間の乾燥ストレスに対する水理学的適応機能の差異
- Nov. 2023 公益財団法人 農学会, 第22回日本農学進歩賞, 巨大で長寿な樹木の生命維持システムと生存戦略の解明
- Dec. 2018 信州山の環境研究センター, 信州フィールド科学賞, “高木の水分生理学的適応様式の解明”
- Mar. 2018 日本森林学会, 第129回日本森林学会大会ポスター優秀賞（防災部門）, 葉の濡れ方が降雨中直後におけるヒノキ林の生態系CO2・潜熱フラックスに及ぼす影響
- Mar. 2018 日本森林学会, 第129回日本森林学会大会ポスター優秀賞（生理部門）, ヒノキ細根の水ポテンシャル及び含水率日変化の現地観測
- 2018 The 18th ECOLOGICAL RESERACH PAPER AWARD, “Tree hollows can affect epiphyte species composition."
- 2017 第128回日本森林学会学生奨励賞, "高さにともなう貯水性の増大に寄与する 日本のスギの高木個体における葉の機能と組織構造"
- 2016 第127回日本森林学会全国大会ポスター賞, "顕微赤外分光法による高木のスギ針葉の水分保持メカニズムの解明"
- 2015 第126回日本森林学会全国大会ポスター賞, "最大樹高に達した異樹齢アカマツにおける葉の生理特性の比較"
- 2014 第 61回日本生態学会全国大会ポスター賞, "秋田スギの梢端葉の水ストレスは貯水機能によって改善される？"
- 2011 第2回日本生態学会近畿地区例会 口頭発表奨励賞, "樹上100ｍの水ストレス？セコイアメスギの葉の水分生理特性"
- There is concern that Japanese cedar (Cryptomeria japonica), which accounts for about 40% of plantation forest in Japan, will become unsuitable for future timber production to drought-induced growth reduction caused by climate change. Drier growing conditions may force trees to rely more on water stored in living tissue. The contribution of stored water relative to daily sap flow in whole-tree water use, is likely to be a key to hydraulic acclimation of trees to climate change. Here, we measured crown and basal sap flow using Granier sensors and point dendrometers in two clonal cultivars of Japanese cedar. The study was conducted from July, 2021 to March, 2023 at the Tano Forest Science Station in Miyazaki Prefecture, southern Japan. In both cultivars, the diurnal peak of sap flow in the crown occurred earlier than at breast height, indicating the use of water stored in stem that complemented water supply from roots to meet transpiration demand. The length of time lags shorter in the early-growth cultivar than in the intermediate-growth cultivar, suggesting stem-stored water contributed less to sustaining sap-flow in the early-growth cultivar under current environmental conditions. A diurnal pattern of stem radial expansion and contraction was observed in both cultivars, suggesting the contribution of water stored in the inner bark. The amplitude of diurnal variation was greater in the crown than at breast height for the early-growth cultivar, while there was no such difference for the intermediate-growth cultivar. When the stem was warmed at breast height, the amplitude of diurnal variation increased only for the early-growth cultivar. This suggests that higher stem temperature may increase the daily use of stem-water storage in Japanese cedar, but that sensitivity and acclimation potential may vary among cultivars.Feb. 2025, Acta Horticulturae, 1(1419) (1419), 135 - 142[Refereed]International conference proceedings
- In living tree trunks, cavitation occurs in the water-conducting tissue, leading to embolism. The occurrence of embolism can be evaluated using the acoustic emission (AE) method, which detects and monitors ultrasonic stress waves released when cavitation occurs. However, long-term measurements have rarely been conducted to understand the factors and patterns of embolism. As tree sap is essential for the transport of nutrients and phytohormones within the tree, elucidating its variation is fundamental to understanding the physiological survival strategies of trees. The aim of this study is to examine the variation of sap flow and embolism in a sapling. We used an olive sapling in our experiment, which was conducted at Kobe University, Japan from May to December 2021. The number of AE events was recorded at 10-min intervals, and the sap flow velocity was measured using a heat flux sensor. Both AE and heat flux sensors are non-destructive measurement methods. In the olive sapling, few AE events were observed after the first irrigation, and the number of AE events gradually increased after 27 days. When irrigation was applied during this period of AE generations, AE events decreased temporarily, but then reoccurred soon after. As described above, we confirmed that the number of AE events in an olive sapling changes in response to irrigation.Feb. 2025, Acta Horticulturae, 1(1419) (1419), 81 - 86[Refereed]International conference proceedings
- Abstract In forests, the distribution of vascular epiphytes is controlled by various environmental factors such as host tree size and substrate type. However, a few studies focused on temperate forests, despite the growing interest in temperate forests with high diversity of accidental epiphytes. This study examined the distribution of accidental and obligate epiphytes on 8 Cercidiphyllum japonicum (Cercidiphyllaceae) trees in a Japanese temperate forest based on observations of 1,301 epiphyte individuals belonging to 49 species. As predicted, the number of species and individuals of accidental and obligate epiphytes increased with host tree size. While the percentage of accidental epiphyte species increased with the host tree size, the percentage of obligate epiphyte species decreased; however, these changes were not significant for the number of individuals. Consistent with our hypothesis, the major rooting substrates of accidental and obligate epiphytes was different. Accidental epiphytes primarily depend on arboreal soil and, to a lesser extent, on moss, but are absent on tree bark. Contrastingly, obligate epiphytes were most frequently found on moss, followed by bark and arboreal soil. These results highlight the impact of host tree size on the diversity of accidental epiphytes compared to obligate epiphytes, suggesting that the host tree size effects are different between accidental and obligate epiphytes in temperate forests. Additionally, a thick accumulation of arboreal soil is crucial for the establishment of accidental epiphytes.Corresponding, Springer Science and Business Media LLC, Sep. 2024, Plant Ecology[Refereed]Scientific journal
- Abstract Fine root morphological traits regulate the belowground resource acquisition strategies of trees. Therefore, investigating genotypic variations isolated from environmental variations within tree species helps in understanding how genotypic backgrounds affect intragenerational tree acclimation to the growing environment. Thus, this study aimed to clarify the effects of genotypic variations on the fine root morphology of three types of Japanese cedar (Cryptomeria japonica), which were derived from different provenances but were grown in a common garden. In the three geographically different provenances of C. japonica stands (Yanase, Yoshino, and Yaku), fine root morphological traits, such as root length and diameter and specific root length (SRL), were measured for each root up to the 4th branching order. Yaku cedar exhibited root traits distinct from the other provenances, such as growing longer and thinner roots in 1st root order to enhance root surface area. In addition, the SRL patterns with root orders and higher root tissue density suggested a resource conservation strategy. Yanase cedar demonstrated a significantly higher root branching ratio and specific root tips than the other provenances, indicating a strategy for investing resources in absorptive roots. Although Yoshino cedar had traits similar to those of Yanase cedar or intermediate between Yanase and Yaku cedars, high aboveground production may be achieved through nutrient acquisition with root exudates instead of absorptive root growth. Genotypic variations appeared in fine root morphological traits of C. japonica trees, even when grown in the same environments, implying distinct resource acquisition strategies characterized by each provenance.Wiley, Jun. 2024, Ecological Research, 39, 717 - 729[Refereed]Scientific journal
- Apr. 2024, Biological Conservation, 292, 110520, English[Refereed]Scientific journal
- Lead, Informa UK Limited, Jan. 2024, Journal of Forest Research, 29(1) (1), 46 - 53, English[Refereed]Scientific journal
- Dec. 2023, Plant Ecology, 224, 1089 - 1095, English[Refereed]Scientific journal
- Sep. 2023, Journal of Forest Research, 28, 345 - 352, English[Refereed]Scientific journal
- Jul. 2023, Applied Forest Science, 32(1) (1), 11 - 19, Japanese[Refereed]Scientific journal
- Wiley, Jan. 2023, Ecological Research, 38(1) (1), 83 - 97, English[Refereed]Scientific journal
- To elucidate the effects of modification of the understory aboveground plant biomass and soil nutrient and moisture environments on canopy tree growth in deer overabundance sites, we compared the canopy shoot growth of oak trees (Quercus crispula), which are not a target for bark stripping or bark feeding by deer, understory aboveground plant biomass, and components of soil nutrient and moisture between inside (protected) and outside (exposed) a large fenced area. We found that canopy shoot growth in the exposed area was reduced compared with that in the protected area. Net nitrogen (N) mineralization rates did not differ between areas, although understory aboveground plant biomass, total carbon (C) and N, and total soil inorganic N content were significantly lower in the exposed area than in the protected area. Indices of canopy shoot growth correlated significantly with soil water content, but due to the limited scope of our study this result does not confirm an effect of soil moisture on canopy shoot growth. Further study is required to clarify the effects of deer overabundance on canopy tree growth.TAYLOR & FRANCIS LTD, Nov. 2022, JOURNAL OF FOREST RESEARCH, 27(6) (6), 469 - 475, English[Refereed]Scientific journal
- Corresponding, Wiley, Aug. 2022, New Phytologist, 235, 1757 - 1766[Refereed]Scientific journal
- Springer Science and Business Media LLC, Jan. 2022, Plant Ecology, 223(1) (1), 99 - 112[Refereed]Scientific journal
- Corresponding, Springer Science and Business Media {LLC}, Nov. 2021, Microbial Ecology, 82, 919 - 931[Refereed]Scientific journal
- Wiley, Oct. 2021, Ecohydrology, 14(7) (7)[Refereed]Scientific journal
- American Geophysical Union ({AGU}), Oct. 2021, Journal of Geophysical Research: Biogeosciences, 126(10) (10)[Refereed]Scientific journal
- Restoring forests has recently received considerable attention in the context of sequestering carbon and supporting biodiversity. Although considering alien species as a tool for natural forest restoration still remains controversial, harnessing alien species when they are already present in an ecosystem might result in overall benefits for nature and society. In this study we evaluated whether the presence of an alien tree species supports or hinders the establishment of naturally regenerating forests in Shiretoko National Park, Japan. In particular, we focused on Larix kaempferi, which is widely present yet non-native to the region, and examined how this alien species affects two factors influencing the success of restoration: wind disturbance and deer herbivory. We examined the following effects of L. kaempferi plantations on natural regeneration: (1) the windbreak function for protecting native tree growth and (2) the nursery function to promote the regeneration of native tree saplings and seedlings under high herbivory pressure. We assessed tree height and regeneration, using large-scale remotely sensed data and terrestrial inventory data in five major vegetation types. We found that L. kaempferi plantations can protect native species from predominant winds. Additionally, L. kaempferi canopy cover promoted abundance and species richness in understory saplings and seedlings compared to other vegetation types such as primary and secondary forests, even under excessive browsing pressure. No regenerating L. kaempferi individuals were observed during the field census, suggesting the species is likely not invasive in our study system. The positive relationship between alien tree species and the regeneration of native tree assemblages emphasizes that existing alien species have the potential to act as nurse plants. Our findings imply that the presence of alien species can contribute to natural forest restoration by improving the local environmental conditions for native species in the short-term. Given the multiple ecological and social needs in our changing world, careful consideration is required to evaluate the long-term consequences of alien species. Especially in ecosystems in which alien species have already established, using their positive functions rather than swiftly eradicating them from the landscape might be beneficial for long-term restoration goals. We conclude that managers need to be aware of the context-dependency of alien species to make restoration more effective.Aug. 2021, Forest Ecology and Management, 493, 119253[Refereed]Scientific journal
- Wiley, Jun. 2021, Plant-Environment Interactions, 2, 112 - 124[Refereed]Scientific journal
- 日本海側（大山，白山，白神山地）と太平洋側（段戸山，三峰山，鷹ノ巣山）のブナ天然林を対象に，ヨーロッパブナで報告された乾燥関連性遺伝子27遺伝子領域の一塩基多型(以下，SNP)のブナへの適用可能性を試みた。その結果，10遺伝子領域がブナに適用可能であり，このうちSNPの変異性の高い4遺伝子領域を選別した。日本海側と太平洋側の地域間における遺伝的分化は非翻訳領域・同義置換領域で認められたが，非同義置換領域では認められなかった。最も集団サイズが小さく孤立化している鷹ノ巣山集団では，非同義置換をともなうSNPの対立遺伝子頻度が他の集団と異なり，アミノ酸の性質に変化をともなう遺伝的浮動の効果の可能性が示唆された。中部森林学会事務局, May 2021, Chubu Forestry Research, (69) (69), 5 - 8, Japanese[Refereed]
- International Society for Horticultural Science (ISHS), Dec. 2020, Acta Horticulturae, (1300) (1300), 105 - 112, No password[Refereed]Scientific journal
- Leaf water storage is a complex interaction between live tissue properties (anatomy and physiology) and physicochemical properties of biomolecules and water. How leaves adsorb water molecules based on interactions between biomolecules and water, including hydrogen bonding, challenges our understanding of hydraulic acclimation in tall trees where leaves are exposed to more water stress. Here, we used infrared (IR) microspectroscopy with changing relative humidity (RH) on leaves of tall Cryptomeria japonica trees. OH band areas correlating with water content were larger for treetop (52 m) than for lower-crown (19 m) leaves, regardless of relative humidity (RH). This high water adsorption in treetop leaves was not explained by polysaccharides such as Ca-bridged pectin, but could be attributed to the greater cross-sectional area of the transfusion tissue. In both treetop and lower-crown leaves, the band areas of long (free water: around 3550 cm-1) and short (bound water: around 3200 cm-1) hydrogen bonding OH components showed similar increases with increasing RH, while the band area of free water was larger at the treetop leaves regardless of RH. Free water molecules with longer H bonds were considered to be adsorbed loosely to hydrophobic CH surfaces of polysaccharides in the leaf-cross sections.Aug. 2020, Plants (Basel, Switzerland), 9(9) (9), 1107, English, International magazine[Refereed]Scientific journal
- Wiley, Jul. 2020, Ecological Research, 35(4) (4), 562 - 574[Refereed]Scientific journal
- Urbanization generally reduces wildlife populations. Individual species responses, however, are often highly variable, and such variability can be explained by differences in species ecological traits. To examine this hypothesis, we focused on two co-occurring land snails, Ezohelix gainesi and Euhadra brandtii sapporo; the former is ground-dwelling and the latter is arboreal. We first estimated their population densities at nine sites distributed along an urbanization gradient: three were located in continuous natural forests, three at the edge of natural forests, and the rest in small isolated forests in urban areas. As a result, the ground-dwelling E. gainesi occurred at highest density in urban forests, followed by forest edges and continuous forests. By contrast, the arboreal E. b. sapporo occurred at highest density in continuous forests, but declined in forest edges and urban forests. We then conducted manipulative field experiments to quantify changes in predation pressure on these species. Ground-tethered E. gainesi and E. b. sapporo were repeatedly predated upon by forest-living mammals in continuous forests, but their survival rates increased in forest edges and urban forests. By contrast, canopy-tethered E. b. sapporo maintained high survival rates in all three forest types. The results indicate that a lack of mammalian predators enables ground-dwelling species to occur at high densities in urban forests, whereas the arboreal species was not affected by this predator relaxation effect. The combination of species-specific behavioural traits and changes in predator communities across an urbanization gradient has important effects on the biodiversity of urban ecosystems.Springer Science and Business Media {LLC}, Jun. 2020, Urban Ecosystems, 23(3) (3), 615 - 616, English[Refereed]Scientific journal
- Tree Health Research Society, Japan, Apr. 2020, Tree and Forest Health, 24(2) (2), 110 - 111, Japanese[Refereed]Scientific journal
- Careful modelling of soil carbon sequestration is essential to evaluate future terrestrial feedback to the earth climate system through atmosphere-surface carbon exchange. Few studies have evaluated, in bio- and geo-applications, parameter and predictive uncertainty of soil respiration models by considering the difference between observations and model predictions; i.e. residual error, which is assumed neither to be independent nor to be described by a normal (i.e. Gaussian) probability distribution with a mean of zero and constant variance. In this paper, we use 2-year observations of soil carbon flux from 2017 to 2018 (hereafter referred to as 'long-term simulation') obtained with two open-top chambers to estimate parameter and predictive uncertainty of a simple soil respiration model based on Bayesian statistics in a cool-temperate forest in western Japan. We also use a Gaussian innovative residual error model in which a generalised likelihood uncertainty estimation that accounts for correlated, heteroscedastic, non-normally distributed (i.e. non-Gaussian) residual error flexibly handles statistics varying in skewness and kurtosis. Results show that the effects of correlation and heteroscedasticity were eliminated adequately. Additionally, the posterior distribution of the residuals had a pattern intermediate to those of Gaussian and Laplacian (or double-exponential) distributions. Consequently, the predicted soil respiration rate, and range of uncertainty therein, well-matched the observational data. Furthermore, we compare results of parameter and predictive inference of the soil respiration model from the long-term simulation with those constrained of short-term simulations (i.e. 4-month subsets of the 2-year dataset) to determine the extent to which the approach used affects the estimation of parameter and predictive uncertainty. No significant difference in parameter estimates was found between the long-term simulation versus any of the short-term simulations, whereas short-term simulation analysis of the uncertainty at 50 %-i.e. between the lower (25 %) and upper (75 %) quartiles of the probability range-indicated distinctive variations in model parameters in summer when more vigorous activity of trees and organisms promotes carbon cycling between the atmosphere and ecosystem. Overall we demonstrate that the Bayesian inversion approach is useful as a means by which to evaluate effectively parameter and predictive uncertainty of a soil respiration model with precise representation of residual errors.ELSEVIER, Feb. 2020, Ecological Modelling, 418, 108918, English[Refereed]Scientific journal
- Urbanization generally reduces wildlife populations. Individual species responses, however, are often highly variable, and such variability can be explained by differences in species ecological traits. To examine this hypothesis, we focused on two co-occurring land snails, Ezohelix gainesi and Euhadra brandtii sapporo; the former is ground-dwelling and the latter is arboreal. We first estimated their population densities at nine sites distributed along an urbanization gradient: three were located in continuous natural forests, three at the edge of natural forests, and the rest in small isolated forests in urban areas. As a result, the ground-dwelling E. gainesi occurred at highest density in urban forests, followed by forest edges and continuous forests. By contrast, the arboreal E. b. sapporo occurred at highest density in continuous forests, but declined in forest edges and urban forests. We then conducted manipulative field experiments to quantify changes in predation pressure on these species. Ground-tethered E. gainesi and E. b. sapporo were repeatedly predated upon by forest-living mammals in continuous forests, but their survival rates increased in forest edges and urban forests. By contrast, canopy-tethered E. b. sapporo maintained high survival rates in all three forest types. The results indicate that a lack of mammalian predators enables ground-dwelling species to occur at high densities in urban forests, whereas the arboreal species was not affected by this predator relaxation effect. The combination of species-specific behavioural traits and changes in predator communities across an urbanization gradient has important effects on the biodiversity of urban ecosystems.SPRINGER, Feb. 2020, Urban Ecosystems, 23, 603 - 614, English[Refereed]Scientific journal
- Because tree size and age co-vary, it is difficult to separate their effects on growth and physiological function. To infer causes for age-related height-growth decline, we compared various leaf traits between mature (ca. 100years) and old (ca. 300years) trees of Pinus densiflora, having similar heights (ca. 30m) and growing in the same stand. For many leaf traits, mature and old trees showed similar height-related trends reflecting acclimation to height-related hydraulic limitation for maintaining photosynthetic and hydraulic homeostasis. Photosynthetic capacity was constant within crowns of both age-classes, though 4.9-5.4mol CO2 m(-2)s(-1) lower for old than for mature trees. Biochemical acclimation of photosynthesis, allocating more nitrogen to treetop leaves, was observed only for mature trees. Leaf turgor loss point was also constant within crowns of both age-classes with no significant effect of age on leaf hydraulic traits. In mature trees, leaf capacitance increased, while bulk tissue elastic modulus decreased with height, whereas opposite height-related trends were observed for old trees. For both age-classes, leaf mass per area (LMA), transfusion-tissue area, and xylem area all increased with height, but LMA was ca. 30gm(-2) greater for old than for mature trees. In old trees, mesophyll area decreased with height, suggesting anatomical acclimation to height may negatively affect photosynthetic capacity. We inferred that old trees rely more on morphological than biochemical acclimation and that such post-maturational shift in resource allocation could underlie height-growth decline of P. densiflora after reproductive maturity.Lead, SPRINGER, Feb. 2019, Oecologia, 189(2) (2), 317 - 328, English[Refereed]Scientific journal
- Because rates of migration and genetic adaptation are slow, individual trees must initially acclimate to climate change via individual-level plasticity. Therefore, when predicting distribution and persistence of tree species under future climate change scenarios, we must take into account geographical variation in intra-individual plasticity. Here, we investigated geographical variation of intra-individual plasticity of Fagus crenata Blume (Japanese beech), a dominant species in late-successional, cool-temperate forests of Japan. We compared within crown variation of leaf morphology (intra-crown leaf plasticity, ILP) among 13 sites across the full distribution range of F. crenata. Generally, ILP was lower for trees in the Pacific than Japan-Sea genetic lineages, low for trees in southern sites, and high for trees in sites near the northern and altitudinal range edges. Among the 13 sites, ILP was correlated with environmental variables associated with temperature. Positive correlation between ILP and temperature variation suggested that environmental perturbation selects for high intra-individual plasticity near northern and altitudinal range edges where F. crenata is expanding its distribution range. On the other hand, low ILP of trees in Pacific and southern sites, comprising geographically isolated populations, may reflect low acclimation potential to environmental perturbation. This could lead to local extinction if climatic conditions exceed the range of tolerance resulting in retreat of the Pacific and southern range edges of F. crenata in Japan.ELSEVIER SCIENCE BV, Dec. 2018, FOREST ECOLOGY AND MANAGEMENT, 429, 437 - 448, English[Refereed]Scientific journal
- Tree hollows often harbor animals and microorganisms, thereby storing nutritive resources derived from their biological activities. The outflows from tree hollows can create unique microenvironments, which may affect communities of epiphytic organisms on trunk surfaces below the hollows. In this study, we tested whether the species richness and composition of epiphytic bryophytes (liverworts and mosses) and lichens differ above and below tree hollows of Aria japonica and Cercidiphyllum japonicum in a Japanese temperate forest. The species richness of epiphytic bryophytes and lichens did not differ above and below hollows; however, the species composition of bryophytes differed significantly above and below hollows. Indicator species analyses showed that the moss species Anomodon tristis and the liverwort species Porella vernicosa were significantly more common below than above hollows, while the liverwort species Radula japonica and four lichen species, including Leptogium cyanescens, occurred more frequently above than below hollows. Our results highlight that tree hollows can produce unique microenvironments on trunk surfaces that potentially contribute to the maintenance of epiphytic diversity on a local scale.SPRINGER JAPAN KK, Sep. 2018, ECOLOGICAL RESEARCH, 33(5) (5), 1079 - 1079, English[Refereed]
- Trees retained during green-tree retention forestry are expected to function as biological legacies that promote biodiversity and enhance ecosystem functions in plantation forests. Investigating how historically retained trees function as biological legacies could help predict the long-term ecological potential of current retention practices. Here, we investigated whether large, retained trees of Cryptomeria japonica D. Don (> 1000 years old) functioned as refugia for persistence of canopy woody plants after logging in a 350-year-old secondary forest in Yakushima, southern Japan. We climbed five each of retained and regenerated trees in a 1-ha research plot, measured trunk and crown structures, and tagged and measured every woody plant stem found on each tree. Compared to regenerated trees, retained trees had twice the surface area available for canopy plant colonization. Moreover, retained trees hosted disproportionately greater abundance of canopy woody plants. Together, the five retained trees hosted 22 species of woody plants comprising 1188 individuals, whereas regenerated trees hosted only 8 species (37 individuals). Combined with our ground-based measurement, canopy woody species contributed 16% of all woody plant species in the plot. Among the five retained trees, woody plant abundance increased markedly with increasing age of trunk breaks. This was because numerous epicormic branches had sprouted below trunk breaks creating large surface area upon which arboreal soil accumulated and woody plants established. Canopy woody plants on retained trees showed wide vertical distribution corresponding to complex crown structure, whereas those on regenerated trees occurred almost exclusively on the lower trunk. Maximum stem size of canopy woody plants was constrained by the volume of arboreal soil upon which they grew. Based on their size structures, we inferred that three species endemic to Yakushima (Vacciniwn yakushimense Makino., Viburnum urceolatwn Sieb. et Zucc., and Rhododendron yakushimanum Nakai), maintain stable populations in the retained trees by sprouting. Several other species scarcely found on the ground were also regenerating in the canopy. Our results demonstrate that retained trees of Cryptomeria functioned as refugia allowing canopy woody plants to persist after logging and give support to the importance of conserving large trees for enhancing biodiversity in forests where canopy plants contribute to species diversity.ELSEVIER SCIENCE BV, Feb. 2018, FOREST ECOLOGY AND MANAGEMENT, 409, 457 - 467, English[Refereed]Scientific journal
- 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.Corresponding, The Ecological Society of Japan, 2018, JAPANESE JOURNAL OF ECOLOGY, 68(2) (2), 125 - 139, Japanese[Refereed]
- Recent studies in the tallest tree species suggest that physiological and anatomical traits of tree-top leaves are adapted to water-limited conditions. In order to examine water retention mechanism of leaves in a tall tree, infrared (IR) micro-spectroscopy was conducted on mature leaf cross-sections of tall Cryptomeria japonica D. Don from four different heights (51, 43, 31 and 19 m). We measured IR transmission spectra and mainly analyzed OH (3700-3000 cm-1) and C-O (1190-845 cm-1) absorption bands, indicating water molecules and sugar groups, respectively. The changes in IR spectra of leaf sections from different heights were compared with bulk-leaf hydraulics. Both average OH band area of the leaf sections and leaf water content were larger in the upper-crown, while osmotic potential at saturation did not vary with height, suggesting higher dissolved sugar contents of upper-crown leaves. As cell-wall is the main cellular structure of leaves, we inferred that larger average C-O band area of upper-crown leaves reflected higher content of structural polysaccharides such as cellulose, hemicellulose and pectin. Infrared micro-spectroscopic imaging showed that the OH and C-O band areas are large in the vascular bundle, transfusion tissue and epidermis. Infrared spectra of individual tissue showed that much more water is retained in vascular bundle and transfusion tissue than mesophyll. These results demonstrate that IR micro-spectroscopy is a powerful tool for visualizing detailed, quantitative information on the spatial distribution of chemical substances within plant tissues, which cannot be done using conventional methods like histochemical staining. The OH band could be well reproduced by four Gaussian OH components around 3530 (free water: long H bond), 3410 (pectin-like OH species), 3310 (cellulose-like OH species) and 3210 (bound water: short H bond) cm-1, and all of these OH components were higher in the upper crown while their relative proportions did not vary with height. Based on the spectral analyses, we inferred that polysaccharides play a key role in biomolecular retention of water in leaves of tall C. japonica.Lead, OXFORD UNIV PRESS, Oct. 2017, Tree physiology, 37(10) (10), 1367 - 1378, English, International magazine[Refereed]Scientific journal
- Compared with stem water storage, leaf water storage is understudied although it may be important for alleviating water stress by contributing quickly and directly to transpiration demand. To quantify the relative contribution of stem versus leaf water storage to daily water deficit, we measured diurnal changes in transpiration rate, sap-flow velocity and stem radius of 10-year-old Cryptomeria japonica D. Don trees. We assumed that the duration of time lags between transpiration rate and sap-flow velocity reflected stored water in the stem and leaf, and that stem volume change represented water content of elastic tissue. The relationship between fresh mass and water potential of the whole tree indicated that the study trees had capacity to store, on average, 91.4 ml of water per kg fresh mass at turgor loss. Leaves, sapwood and elastic tissue contributed around 51%, 29% and 20% of stored water, respectively. During morning, transpiration rates were higher than sap-flow velocity suggesting depletion of stored water. During the first 2 h after onset of transpiration, stored water contributed more than 100% of whole-tree transpiration. Depletion of leaf water (P-Leaf) and sapwood water (P-Sap) coincided with the onset of transpiration and became maximum around 15:00 h. Depletion of elastic tissue water (P-Elastic) lagged behind that of P-Leaf and P-Sap by 1-2 h, indicating that replenishment of stored water occurs late in the day when low leaf water potentials resulting from daytime transpiration drive water uptake. Maximum depletion of P-Leaf was about 1-3 times and 5-10 times that of P-Sap and P-Elastic, respectively. The contribution of P-Leaf to total daily transpiration was 5-8%, while those of P-Sap and P-Elastic were 3-4% and 0.7-1%, respectively. Our results suggest the importance of leaf water storage in maintaining daily transpiration in young C. japonica trees.Corresponding, OXFORD UNIV PRESS, Oct. 2017, TREE PHYSIOLOGY, 37(10) (10), 1394 - 1403, English, International magazine[Refereed]Scientific journal
- Cupressoid (scale-like) leaves are morphologically and functionally intermediate between stems and leaves. While past studies on height acclimation of cupressoid leaves have focused on acclimation to the vertical light gradient, the relationship between morphology and hydraulic function remains unexplored. Here, we compared physiological and morphological characteristics between treetop and lower-crown leaves of 100-year-old Chamaecyparis obtusa Endl. trees (~27 m tall) to investigate whether height-acclimation compensates for hydraulic constraints. We found that physiological acclimation of leaves was determined by light, which drove the vertical gradient of evaporative demand, while leaf morphology and anatomy were determined by height. Compared with lower-crown leaves, treetop leaves were physiologically acclimated to water stress. Leaf hydraulic conductance was not affected by height, and this contributed to higher photosynthetic rates of treetop leaves. Treetop leaves had higher leaf area density and greater leaf mass per area, which increase light interception but could also decrease hydraulic efficiency. We inferred that transfusion tissue flanking the leaf vein, which was more developed in the treetop leaves, contributes to water-stress acclimation and maintenance of leaf hydraulic conductance by facilitating osmotic adjustment of leaf water potential and efficient water transport from xylem to mesophyll. Our findings may represent anatomical adaptation that compensates for hydraulic constraints on physiological function with increasing height.OXFORD UNIV PRESS, Oct. 2017, Tree physiology, 37(10) (10), 1327 - 1336, English, International magazine[Refereed]Scientific journal
- 応用森林学会, Aug. 2017, 森林応用研究, 26(2) (2), 1 - 7, JapaneseRegional differences in morphological plasticity of leaves of Fagus crenata[Refereed]
- Tree hollows often harbor animals and microorganisms, thereby storing nutritive resources derived from their biological activities. The outflows from tree hollows can create unique microenvironments, which may affect communities of epiphytic organisms on trunk surfaces below the hollows. In this study, we tested whether the species richness and composition of epiphytic bryophytes (liverworts and mosses) and lichens differ above and below tree hollows of Aria japonica and Cercidiphyllum japonicum in a Japanese temperate forest. The species richness of epiphytic bryophytes and lichens did not differ above and below hollows; however, the species composition of bryophytes differed significantly above and below hollows. Indicator species analyses showed that the moss species Anomodon tristis and the liverwort species Porella vernicosa were significantly more common below than above hollows, while the liverwort species Radula japonica and four lichen species, including Leptogium cyanescens, occurred more frequently above than below hollows. Our results highlight that tree hollows can produce unique microenvironments on trunk surfaces that potentially contribute to the maintenance of epiphytic diversity on a local scale.WILEY, Jul. 2017, ECOLOGICAL RESEARCH, 32(4) (4), 503 - 509, English[Refereed]Scientific journal
- Apr. 2017, 樹木医学研究, 21(2) (2), 81‐82, Japanese, Domestic magazine[Refereed]Scientific journal
- THE JAPANESE FORESTRY SOCIETY, Apr. 2017, Journal of the Japanese Forest Society, 99(2) (2), 74 - 83, Japanese
Water transport in tall trees occurs over long-distances from roots to leaves, as well as against the gravitational hydrostatic gradient. The resulting water stress and physiological/morphological constraints of treetop leaves was considered the main cause of height-growth limitation. In tall trees, there is functional trade-off of xylem hydraulic efficiency relative to hydraulic safety and water-stress adaptation. In addition, xylem hydraulic properties affect photosynthetic production by regulating CO2 uptake through stomata and resource allocation. Because the well-illuminated treetop environment can yield potentially high photosynthetic production, researchers have suggested mechanisms that allow tall trees to adapt/acclimate to, or compensate for, hydraulic limitation. Recent research has revealed new insights, such as structural characteristics of xylem cells for hydraulic efficiency and safety, adaptation/acclimation of xylem structure and function to increasing height, and hydraulic capacitance of leaf and sapwood that compensates for hydraulic limitation. New findings have revealed variability of hydraulic architecture due to high phenotypic plasticity and short-term changes in hydraulic conductivity within tall trees. In tall trees, the water transport pathway connecting soil-plant-atmosphere is not a simple circuit consisting only of resistances, but includes circuit-breaker-like safety buffers and capacitor-like storage mechanisms. Further research should elucidate, in its entirety, the hydraulic architecture of tall trees, and lead to integrated understanding tall-tree ecophysiology.
[Refereed] - Tree Health Research Society, Japan, Jan. 2017, Tree and Forest Health, 21(1) (1), 22 - 23, Japanese[Refereed]
- Springer Verlag, Jun. 2016, Trees - Structure and Function, 30(3) (3), 1019, English[Refereed]Scientific journal
- The tallest trees of Cryptomeria japonica occur in climatic regions similar to the world's tallest trees. We hypothesized that tall C. japonica trees would have evolved adaptive mechanisms to overcome height growth limitation. Here, we focused on foliar water storage, a mechanism recently discovered in Sequoia sempervirens. In C. japonica, leaf water potential at turgor loss did not change with height or light availability, while leaf hydraulic capacitance and succulence (water content per leaf surface area) increased, suggesting hydraulic compensation. Plasticity of leaf morphology could contribute to avoiding negative effects of height on photosynthesis. We also focused on the structure and function of transfusion tissue in leaves and its role in water storage and supply. Cross-sectional area of transfusion tissue increased with height, whereas that of xylem was constant. We confirmed that water flowed from vascular bundle to mesophyll via the transfusion tissue. Cryo-scanning electron microscopy images of leaf cross sections showed that transfusion cells were flattened, but not fully dehydrated when leaf water potential decreased in situ and by experimental dehydration, and cell deformation was more marked for treetop leaves than for lower-crown leaves. The shape of transfusion cells recovered at predawn as well as after experimental rehydration. As in S. sempervirens, transfusion tissue of C. japonica may function as a hydraulic buffer, absorbing and releasing water according to leaf water status. Anatomical and hydraulic properties contributing to foliar water storage may be an adaptive mechanism acquired by tall Cupressaceae trees to overcome the hydraulic constraints on physiological function with increasing height.Lead, SPRINGER HEIDELBERG, Feb. 2016, TREES-STRUCTURE AND FUNCTION, 30(1) (1), 141 - 152, English[Refereed]Scientific journal
- We evaluated vegetation condition on a cutting slope revegetated by “transplanting method of top-soil blocks” in 13 years after construction: cutting top-soil around the developed area into blocks and transplanting on a slope surface. We confirmed 90 % vegetation coverage, no slope failure, and proceeding succession on the slope. We observed poor tree height growth on the slope suggested that tree roots could not penetrate enough below the top-soil blocks, due to unweathering mother rock. On the other hand, we also confirmed occurrence of Pinus densiflora and coppicing of woody species in a pine stand, such as Rhododendron reticulatum, from the top-soil blocks. According to these results, we concluded that “transplanting method of top-soil blocks” was meaningful to vegetation restoration.JAPANESE SOCIETY OF REVEGETATION TECHNOLOGY, 2016, Journal of the Japanese Society of Revegetation Technology, 42(1) (1), 15 - 20, Japanese[Refereed]
- The larvae of Japanese gypsy moth (JGM, Lymantria dispar japonica) are highly polyphagous and considered a serious pest that cause significant ecological and economic losses in forests. Monitoring of egg masses is important to prevent large outbreaks of JGM from occurring in their native range. To investigate oviposition site selection by JGM, we analyzed the occurrence and spatial distribution of egg masses across various evergreen tree species within a secondary forest dominated by evergreen broad-leaved trees in western Japan, following a large outbreak. Egg masses were concentrated on the abaxial surfaces of the leaves of a few evergreen tree species. There was a strong preference for Camellia japonica L., on which more than 75% of the egg masses were found. Egg masses were only found on evergreen tree species with large leaves (leaf area >10 cm(2) and leaf dry mass >0.1 g). The spatial distribution of egg masses were clustered at scales around 1-2 m. For effective monitoring of JGM egg masses in warm-temperate evergreen broad-leaved forests of Japan, the abaxial surfaces of the most abundant evergreen broadleaved trees with large leaves should be checked. If egg masses are found, it is likely that nearby trees of the same species will also have egg masses. Large trees should be checked thoroughly for occurrence of multiple egg masses.TAYLOR & FRANCIS LTD, 2016, FOREST SCIENCE AND TECHNOLOGY, 12(3) (3), 130 - 136, English[Refereed]Scientific journal
- To integrate human-disturbed hillslopes with the regional landscape, natural forest restoration has become an important objective of hillslope re-vegetation in Japan. At Kobe Municipal Sports Park (KMSP), seedlings of native species were planted in 1980 to restore semi-natural secondary forest (satoyama) in an urban setting. Here, we present 21 years of stand dynamics based on vegetation surveys conducted in 1992, 2000, and 2013 in two research plots (control and managed) at KMSP in relation to a reference forest to evaluate management effects and restoration success. Total basal area continued to increase in both the plots, but diameter-growth decreased in the control plot, whereas it continued to increase in the managed plot, which had been thinned by volunteers. In the control plot, which was planted at higher initial density than the managed plot, Quercus phillyraeoides (evergreen, mid-canopy tree) dominated the single-layered canopy and vertical development was delayed. In the managed plot, Quercus serrata (deciduous, canopy tree) dominated the upper canopy layer and evergreen broadleaved trees dominated the mid- to lower-canopy layers, resulting in a vertically well-developed canopy similar to the reference forest. The basal area of Robinia pseudoacacia decreased due to shading by evergreen trees, whereas that of Nerium oleander, an exotic species, had increased in the control plot. Ordination results indicated that vegetation of the control plot was diverging away from the reference forest, whereas thinning had directed the managed plot toward it. Our results confirm that simultaneously planting seedlings of native species does not lead to natural forest stand structure. In the future, adaptive management, such as periodic thinning, removal of shade-tolerant, exotic species and enrichment planting of native species, will be needed to integrate forest restoration sites with the surrounding mid-successional, secondary forest. (C) 2015 Elsevier GmbH. All rights reserved.ELSEVIER GMBH, URBAN & FISCHER VERLAG, 2015, URBAN FORESTRY & URBAN GREENING, 14(2) (2), 309 - 314, English[Refereed]Scientific journal
- 1. The constraint on vertical water transport is considered an important factor limiting height growth and maximum attainable height of trees. Here, we show evidence of foliar water storage as a mechanism that could partially compensate for this constraint in Sequoia sempervirens, the tallest species. 2. We measured hydraulic and morpho-anatomical characteristics of foliated shoots of tall S.sempervirens trees near the wet, northern and dry, southern limits of its geographic distribution in California, USA. 3. The ability to store water (hydraulic capacitance) and saturated water content (leaf succulence) of foliage both increased with height and light availability, maintaining tolerance of leaves to water stress (bulk-leaf water potential at turgor loss) constant relative to height. 4. Transverse-sectional area of water-storing, transfusion tissue in leaves increased with height, while the area of xylem tissue decreased, indicating increasing allocation to water storage and decreasing reliance on water transport from roots. 5. Treetop leaves of S.sempervirens absorb moisture via leaf surfaces and have potential to store more than five times the daily transpirational demand. Thus, foliar water storage may be an important adaptation that helps maintain physiological function of treetop leaves and hydraulic status of the crown, allowing this species to partially compensate for hydraulic constraints and sustain turgor for both photosynthesis and height growth.Lead, WILEY, Oct. 2014, FUNCTIONAL ECOLOGY, 28(5) (5), 1087 - 1093, English[Refereed]Scientific journal
- In fragmented and abandoned forests near urban areas, vegetation succession often follows a plagiosere, but the direction of succession may vary depending on the surrounding landscape. We investigated edge effects and five-year change in stand structure of an abandoned secondary deciduous forest located adjacent to agricultural fields and near lucidophyllous forest. In the secondary forest, the number and basal area of evergreen-species increased, while many small individuals of deciduous species died. Size, number, and basal area of evergreen species increased from forest edge to interior, while mortality of deciduous species increased during the five-year study period. Although newly established trees included many bird-dispersed species, more than half of these were lucidophyllous forest components, dispersal was not concentrated near the forest edge, and no ornamental or invasive species were observed. Thus, we inferred that the vegetation change in the secondary forest is not following a plagiosere.We predict that evergreen species will spread from the interior toward the forest edge, shade-tolerant evergreen species will increase in the lower canopy, and tree species composition of the secondary forest will become more similar to the nearby lucidophyllous forest. In a landscape where mature forests may function as seed sources, vegetation change in fragmented and abandoned forests may not divert to a plagiosere.Lead, THE JAPANESE FORESTRY SOCIETY, 2014, Journal of the Japanese Forest Society, 96(2) (2), 75 - 82, Japanese[Refereed]
- Because of their overwhelming size over other organisms, trees define the structural and energetic properties of forest ecosystems. From grasslands to forests, leaf area index, which determines the amount of light energy intercepted for photosynthesis, increases with increasing canopy height across the various terrestrial ecosystems of the world. In vertically well-developed forests, niche differentiation along the vertical gradient of light availability may promote species coexistence. In addition, spatial and temporal differentiation of photosynthetic traits among the coexisting tree species (functional diversity) may promote complementary use of light energy, resulting in higher biomass and productivity in multi-species forests. Trees have evolved retaining high phenotypic plasticity because the spatial/temporal distribution of resources in forest ecosystems is highly heterogeneous and trees modify their own environment as they increase nearly 1,000 times in size through ontogeny. High phenotypic plasticity may enable coexistence of tree species through divergence in resource-rich environments, as well as through convergence in resource-limited environments. We propose that the breadth of individual-level phenotypic plasticity, expressed at the metamer level (leaves and shoots), is an important factor that promotes species coexistence and resource-use complementarity in forest ecosystems. A cross-biome comparison of the link between plasticity of photosynthesis-related traits and stand productivity will provide a functional explanation for the relationship between species assemblages and productivity of forest ecosystems.SPRINGER JAPAN KK, Mar. 2013, ECOLOGICAL RESEARCH, 28(2) (2), 191 - 198, English[Refereed]Scientific journal
- Cinnamomum camhora (L.) Sieb. is widely planted in many shrines and temples in Japan. To develop methods for genetic conservation of natural heritage trees and endemic evergreen broadleaved forests comprising this species, we tested the possibility of using plant cuttings for regeneration of old C. camphoratrees. The survival rate of cuttings taken from trees more than 100 years old was about 10%. The cuttings maintained some parent-tree traits, but early growth after establishment was greater than that of the seedlings. The leaves of cuttings showed higher photosynthetic rate earlier in the growing season than the seedlings and were more tolerant of water stress. These results suggested that if enough plants can be obtained, old C. camphoratrees can be regenerated from cuttings.Lead, JAPANESE SOCIETY OF REVEGETATION TECHNOLOGY, Aug. 2011, The Japanese Association of The Revegetaion Technology, 37(1) (1), 21 - 25, Japanese[Refereed]
- 2024, 日本森林学会大会学術講演集, 135thヤクスギ林冠と地上土壌における菌根菌群集の比較
- 2023, 日本地球惑星科学連合大会予稿集(Web), 2023Seasonal and daily variation of methane emissions from the stem surfaces of Alnus japonica
- 2023, 日本農業気象学会全国大会講演要旨(CD-ROM), 2023湿地性樹木の樹幹からのメタン放出について-最近の動向および我々の研究-
- 2022, 根の研究, 31同一環境下で生育した異なる産地由来のスギ細根形態の比較
- Lead, Oct. 2021, 地域自然史と保全, 43(1) (1), 71 - 82, 071-082 東.pdf, No password老齢天然林に生残する巨樹の生態学的視点からの保全価値の再評価 ―芦生研究林内保存木の維管束着生植物群集と林冠土壌―
- 2021, 日本地球惑星科学連合大会予稿集(Web), 2021Seasonal variation and controlling factors of stem methane emissions from Alnus japonica revealed by continuous measurements
- 2020, 日本農業気象学会全国大会講演要旨(CD-ROM), 2020 (CD-ROM)温帯林の湿地におけるハンノキ樹幹からのメタン放出の季節変動
- Sep. 2019, AsiaFlux2019 Conference Proceedings, 153 - 153, EnglishHydraulic characteristics and water storage of Japanese cypress using sap flow rate and water potential measurementsIntroduction international proceedings
- Lead, Sep. 2019, AsiaFlux2019 Conference Proceedings, 154 - 154, EnglishContribution of whole-tree water storage to daily transpiration in conifer treesIntroduction international proceedings
- Sep. 2018, The 2018 joint 14 th iCACGP quadrennial symposium and 15 th IGAC science conference, EnglishMethane emission from the stems of Alnus japonica in riparian wetlands within a temperate forest catchment
- Lead, 2015, 山岳雑誌 岳人, 44 - 45, Japanese, 044-045-2.pdf, No password巨樹を見る目が変わるー世界一高い木レッドウッドIntroduction commerce magazine
- 全国森林病虫獣害防除協会, 2015, 森林防疫, 64(4) (4), 15 - 19, Japanese樹病研究最近の動向 : 第126回日本森林学会大会より
- Lead, 2014, What’s Up? The Newsletter of the International Canopy Network, 20, 1 - 2, English, Image.pdf, No passwordClimbing and Researching the Tallest Trees in Japan.Introduction scientific journal
- Contributor, 木からメタンが出るってほんとうなの？, 文研出版, Dec. 2023, 34-35, Japanese, ISBN: 9784580825994くらしと根っこはつながっている?
- Contributor, 木のてっぺんまでどうやって水がとどくの？, 文研出版, Dec. 2023, 26-27, Japanese, ISBN: 9784580825994くらしと根っこはつながっている?
- Contributor, 樹高１００メートルの世界から, 文一総合出版, Apr. 2018, Japanese, ISBN: 9784829971079生物学者、地球を行く : まだ知らない生きものを調べに、深海から宇宙まで
- 第136回日本森林学会大会TreeQSMを用いた広葉樹測定精度の検証Oral presentation
- 第136回日本森林学会大会兵庫県南東部における社叢林土壌は優占種によりどのような影響を受けるのかPoster presentation
- 第136回日本森林学会大会Effects of stem heating on cambial growth of Cryptomeria japonica in a 50-year-old plantation in southwestern JapanPoster presentation
- 第136回日本森林学会大会ヤクスギ巨樹上の林冠土壌中の微生物群集の解明Poster presentation
- 第136回日本森林学会大会九州産スギ2品種の日常的な幹の貯留水利用Poster presentation
- International Symposium on Wood Science and Technology 2025 (ISWST2025)Intra-individual vessel variation in the axial and radial direction of Para rubber tree (Hevea brasiliensis)[Invited]Poster presentation
- International Symposium on Wood Science and Technology 2025 (ISWST2025)How much lumber can be obtained from Konara oak in Satoyama?[Invited]Poster presentation
- 日本生態学会第72回全国大会京都府の冷温帯林における景観規模でのカブトゴケ属（Lobaria）のITS多様性の解明Poster presentation
- 日本生態学会第72回全国大会根系露出によるブナ地上部生理機能の変化Poster presentation
- 日本生態学会第72回全国大会半島マレーシア熱帯低地林における高木種の生理生態学的特性Nominated symposium
- 10th Pacific Regional Wood Anatomy Conference (10th PRWAC)Relationship between leaf transfusion tissue and drought acclimation among Cryptomeria japonica populations.Poster presentation
- 10th Pacific Regional Wood Anatomy Conference (10th PRWAC)Intra-individual variations in vessel diameter in rubberwood (Hevea brasiliensis)Poster presentation
- 10th Pacific Regional Wood Anatomy Conference (10th PRWAC)How much valuable furniture lumber can be obtained from Japanese broadleaf trees?Poster presentation
- 日本生態学会第71回全国大会, JapaneseMammal and bird communities in canopy ecosystems of old-growth Cryptomeria forests in Yakushima Island with a special focus on effects of loggingPoster presentation
- 日本生態学会第71回全国大会, EnglishMicrobial communities associated with nitrogen transformation in canopy soils on large cedars in Yakushima,JapanOral presentation
- 日本生態学会第71回全国大会, JapaneseEffects of forest management methods on the soil environment and fungal community at Mt. RokkoPoster presentation
- 日本生態学会第71回全国大会, JapaneseGeographical variation in Japanese cedar shapes nutrient dynamics through bedrockPoster presentation
- 日本生態学会第71回全国大会, JapaneseCanopy environments supporting epiphytes on large, old trees and their ecological rolesNominated symposium
- 日本生態学会第71回全国大会, JapaneseEnvironmental factors influencing the amonut of litter of epiphytic lichen in forest ecosystemsPoster presentation
- 第135回日本森林学会大会, JapaneseEffects of soil erosion on leaf physiological characteristics in a beech forest in Kyushu, JapanPoster presentation
- 第135回日本森林学会大会, JapaneseMycorrhizal fungal communities of canopy and ground soils in large Cryptomeria japonica in Yakushima, JapanPoster presentation
- 第135回日本森林学会大会, JapaneseDifferences of hydraulics acclimation against drought between natural populations of SugiPoster presentation
- 2023年生態学会近畿地区会大会, Dec. 2023, Japaneseアセビの通水阻害に対する通水回復機能の検討Oral presentation
- 2023年生態学会近畿地区会大会, Dec. 2023, Japanese大型地衣類カブトゴケ属リターの分解に本属の地衣成分と分解者群集が与える影響Oral presentation
- the 12th International Workshop on Sap Flow, EnglishDiurnal and seasonal changes in acoustic emissions and sap flow in living tree trunksPoster presentation
- the 12th International Workshop on Sap Flow, EnglishThe daily use of stem-water storage in two clonal cultivars of Japanese cedar estimated from sap flow and dendrometerOral presentation
- 第 54 回日本緑化工学会大会, Japaneseシマトネリコ生立木における幹の通水阻害に関わる環境要因Poster presentation
- 第134回日本森林学会大会, JapaneseShoot growth of canopy tree Quercus crispula and soil nitrogen availability under the high deer densityPoster presentation
- 第134回日本森林学会大会, JapaneseEffects of host tree size and substrate types on the distribution of vascular epiphytes in a old-growth temperate forestPoster presentation
- 第134回日本森林学会大会, JapaneseTranscriptome analysis in response to trunk heating between Japanese cedar clones with different growth characteristicsPoster presentation
- 第134回日本森林学会大会, JapanesePotential use of stem water storage for daily transpiration in tall Japanese black pinePoster presentation
- 第134回日本森林学会大会, JapaneseAn attempt to evaluate tree water relations based on the frequency of acoustic emissionsPoster presentation
- 日本生態学会第70回全国大会, JapaneseDecomposition of epiphytic lichens and bryophytes on the ground and in the forest canopyPoster presentation
- 日本生態学会第70回全国大会, JapaneseMetagenomic analyses of the invertebrate diversity supported by canopy soil of old growth Cryptomeria japonica forest in YakushimaPoster presentation
- 日本生態学会第70回全国大会, JapaneseHow does light quality influence photosynthesis and carbon allocation of plants?Nominated symposium
- 日本地衣学会第21回大会, Japanese日本産 Lecanora yasudae 様菌類の遺伝学的多様性についてPoster presentation
- 2022年生態学会近畿地区会大会, Dec. 2022, Japaneseアコースティックエミッション法によるシマトネリコの通水阻害の評価Oral presentation
- 2022年生態学会近畿地区会大会, Dec. 2022, Japanese大型葉状地衣類Lobaria属の地上および林冠における初期分解特性Oral presentation
- iLEAPS-Japan 研究集会 2022Methane emission from the stem surfaces of Alnus japonica
- IUFRO OKINAWA 2022, EnglishQuantitative and qualitative survey for wood utilization from abandoned satoyama secondary forests in JapanPoster presentation
- IUFRO OKINAWA 2022, EnglishClimate-growth response of Cryptomeria japonica cultivars in Kyushu, JapanPoster presentation
- The INTECOL 2022 Congress, Aug. 2022, English, INTECOL2022.pdf, No passwordRecognizing conservation values of large, old trees in a template old-growth forest from an ecological contextPoster presentation
- 第133回日本森林学会大会, Japaneseヤクスギ・アキタスギにおける仮道管径の幹基部への拡大と樹齢・樹高の関係Poster presentation
- 日本生態学会第69回全国大会, Japanese亜高山帯に生育する常緑樹と落葉樹の葉の水利用特性と標高との関係Poster presentation
- 日本生態学会第69回全国大会, Japanese西日本のブナ天然林における11年間のブナ実生個体群動態Poster presentation
- 第133回日本森林学会大会, Mar. 2022, Japaneseスギの葉における貯水性－細胞壁への水分子の吸着に着目して―[Invited]Oral presentation
- 第133回日本森林学会大会, JapaneseNFCタグによる立木カタログ化で里山広葉樹材の活用を展開するOral presentation
- 第133回日本森林学会大会, Japanese電子タグによる広葉樹立木の質・量的記録と管理手法の開発Poster presentation
- 日本生態学会大会講演要旨(Web), 2022Towards an understanding of the biomass and distribution of epiphytic bryophytes and suspended soils on single trees
- 2021年度 日本生態学会近畿地区会, Dec. 2021放棄里山二次林は照葉樹林に遷移するのか？
- The 2nd International Electronic Conference on Forests — Sustainable Forests: Ecology, Management, Products and Trade, Sep. 2021Spatial and temporal variation of species composition and structure of unmanaged secondary forest (abandoned satoyama) adjacent to late-successional forest
- 日本景観生態学会 第31回信州大会, Sep. 2021六甲山上の自然地形を生かしたゴルフ場の森林環境の把握
- The 9th EAFES International Congress, Jul. 2021Predicting succession of unmanaged secondary forest from spatio-temporal variation of stand structure relative to the adjacent late-successional forest
- The Japanese Forest Society Congress, May 2021, Japanese, THE JAPANESE FORESTRY SOCIETY, [in Japanese]Water adsorption to leaf cross-section of tall Cryptomeria japonica with IR spectroscopy under relative humidity control
- 第132回日本森林学会大会, Mar. 2021遷移後期の照葉樹林に隣接する天然生二次林における15年間の植生動態
- 第132回日本森林学会大会, Mar. 2021ブナの葉の個体内変異とその地域間差：気候変動への順化予測を目指して
- 日本生態学会第68回全国大会, Mar. 2021乗鞍岳の高木限界に優占する落葉広葉樹と常緑針葉樹の光合成および水分生理特性
- 日本生態学会第68回全国大会, Mar. 2021植物生理生態―生態学研究におけるモデル生物としてのスギの可能性
- 日本生態学会第68回全国大会, Mar. 2021Height-related adaptation of xylem structure and limitation of vessel widening of Old trees.
- 日本生態学会第67回全国大会, Mar. 2020, Japanese森林再生における外来種の可能性：国内外来種カラマツの役割Poster presentation
- 第131回日本森林学会大会, Mar. 2020, Japanese熱帯低地林におけるフタバガキ科高木種の水利用特性Poster presentation
- 第131回日本森林学会大会, Mar. 2020, Japaneseシカによる下層植生採食がミズナラ林冠木の成長と繁殖に及ぼす間接的影響Poster presentation
- 第131回日本森林学会大会, Mar. 2020, Japanese高木限界に生育する樹木 4 種の細根の水および炭素利用様式Oral presentation
- 第131回日本森林学会大会, Mar. 2020, Japanese日本各地のブナ集団における葉の形態的可塑性の地理的変異Public symposium
- 日本生態学会第67回全国大会, Mar. 2020, English森林の分断化が陸産出貝類に与える影響Oral presentation
- 日本生態学会第67回全国大会, Mar. 2020, Japanese高木限界に生育する樹木4種の光合成および水利用特性Oral presentation
- 日本生態学会第67回全国大会, Mar. 2020, Japanese亜高山帯に生育するダケカンバとオオシラビソにおける葉の水分特性の標高間比較Poster presentation
- 第50回記念根研究集会, Nov. 2019, Japanese高木限界の樹木４種における細根の吸水および通水特性Poster presentation
- 2019年度「樹木年輪」研究会・2019年度組織と材質研究会秋季シンポジウム, Nov. 2019, Japanese同一環境下に生育する産地の異なるスギ3集団における幹の肥大成長と気候との関係Poster presentation
- XI International workshop on Sap flow, Oct. 2019, EnglishFunctional strategy of lianas Wisteria and Actinidia spp. against drought stress: The role of axial parenchyma and narrow vesselsOral presentation
- XI International workshop on Sap flow, Oct. 2019, EnglishFunctional strategy of Cinnamomum camphora to recover embolism and survive the drought conditionPoster presentation
- XI International workshop on Sap flow, Oct. 2019, EnglishTime lags between crown and basal sap flows in tropical broadleaf and temperate conifer treesOral presentation
- IGAC-iLEAPS joint meeting, Sep. 2019, EnglishMethane emission from woody stem and its potential impact on atmospheric methane budget[Invited]
- 日本地球惑星科学連合2019年大会, May 2019, Japanese高木の樹高成長における水分生理学的適応[Invited]Invited oral presentation
- 日本生態学会第66回全国大会, Mar. 2019, EnglishInfluence of intermittent seed production on canopy growth and seedling recruitment in Fagus crenataPublic symposium
- 第129回日本森林学会大会, Mar. 2019, Japanese葉の濡れ方が降雨中・直後のヒノキ林ＣＯ２・潜熱フラックスに及ぼす影響Poster presentation
- 第130回日本森林学会大会, Mar. 2019, Japanese森林限界の樹木4種における細根水吸収・輸送の解明Poster presentation
- 第130回日本森林学会大会, Mar. 2019, Japanese森林限界の樹木４種における水利用特性の解明Poster presentation
- 日本生態学会第66回全国大会, Mar. 2019, EnglishHeight-related variations of leaf traits reflect strategies for maintaining photosynthetic and hydraulic homeostasis in tall Pinus densiflora treesPublic symposium
- 日本生態学会第66回全国大会, Mar. 2019, Japanese樹液流および水ポテンシャル測定を用いたヒノキの貯留・通水特性の評価Poster presentation
- 日本生態学会第66回全国大会, Mar. 2019, Japaneseシカによる下層植生の採食はミズナラ林冠木のシュートレベルでの成長と繁殖を抑制するPoster presentation
- 日本生態学会第66回全国大会, Mar. 2019, English都市化によって増えるカタツムリと減るカタツムリ －捕食パラドックスの検証ーPoster presentation
- 第 49 回根研究集会, Oct. 2018, Japanese乗鞍岳森林限界境界における樹木4種の細根形態および水分生理特性Poster presentation
- 水文・水資源学会2018年度研究発表会, Sep. 2018, Japanese土壌－根－幹－枝－葉の水ポテンシャル観測によるヒノキの水利用評価Oral presentation
- 水文・水資源学会2018年度研究発表会, Sep. 2018, Japanese熱帯雨林における蒸発散の恒常性についてOral presentation
- The 8th EAFES (East Asian Federation of Ecological Societies) International Congress, Apr. 2018, EnglishLarge Cryptomeria trees retained after intensive logging functioned as refugia for canopy woody plantsin YakushimaPoster presentation
- The 8th EAFES (East Asian Federation of Ecological Societies) International Congress, Apr. 2018, EnglishCanopy vascular plant community and arboreal soil characteristics on a large, long-lived Cercidiphyllumjaponicumtreein temperate forest, Japan.Poster presentation
- 第128回日本森林学会大会, Mar. 2018, Japanese水分特性曲線法を用いたヒノキの樹体内貯留量と蒸散への寄与度の評価Poster presentation
- 第129回日本森林学会大会, Mar. 2018, Japaneseヒノキ細根の水ポテンシャル及び含水率日変化の現地観測Poster presentation
- 日本生態学会第65回全国大会, Mar. 2018, Japanese顕微赤外分光法によるスギ高木の針葉における水分保持メカニズムの解明Public symposium
- 日本生態学会第65回全国大会, Mar. 2018, Japaneseシカによる下層植生の食害がミズナラのシュート成長に及ぼす影響Poster presentation
- 日本生態学会第65回全国大会, Mar. 2018, Japanese芦生研究林内保存木の保全生態学的研究ー着生植物群集と林冠土壌ーPoster presentation
- The 9th PRWAC & IAWS Meeting, Sep. 2017, EnglishSeasonal changes of leaf photosynthetic rate, stored starch and vessel formation in shoots and tree stems of two deciduous broad-leaved tree species.Poster presentation
- 2017年度日本森林学会授賞式・受賞者講演会, Mar. 2017, JapaneseFunction and structure of leaves contributing to increasing water storage with height in the tallest Cryptomeria japonica trees of Japan[Invited]Invited oral presentation
- 第128回日本森林学会大会, Mar. 2017, Japaneseプレッシャーチャンバー法を用いたヒノキ根の水分特性の測定Poster presentation
- 第128回日本森林学会大会, Mar. 2017, Japanese気候条件からみたブナの葉の表現型可塑性Poster presentation
- 日本生態学会第64回全国大会, Mar. 2017, Japaneseブナの表現型可塑性とその地域変異Poster presentation
- 日本生態学会第64回全国大会, Mar. 2017, JapaneseDipterocurpus sublamellatusの高所における葉の水分生理特性Poster presentation
- 樹木医学会第21回大会, Nov. 2016, Japaneseコノテガシワ園芸品種における葉枯れは水ストレスが関与している？Poster presentation
- 樹木医学会第21回大会, Nov. 2016, Japaneseヒノキの樹液流速度の日変化パタンにおける垂直変異と幹貯留水Poster presentation
- 第127回日本森林学会大会, Mar. 2016, JapaneseWhole-tree pressure volume法とデンドロメーター法を用いたスギの貯留水の測定と水輸送におけるその役割Poster presentation
- 第127回日本森林学会大会, Mar. 2016, Japanese１００年生ヒノキ鱗状葉の通水性維持機構Poster presentation
- 第127回日本森林学会大会, Mar. 2016, Japanese顕微赤外分光法による高木のスギ針葉の水分保持メカニズムの解明Poster presentation
- 日本生態学会第63回全国大会, Mar. 2016, Japaneseヒノキ樹冠部における鱗状葉の通水性維持-transfusion tissueの役割Poster presentation
- 日本生態学会第63回全国大会, Mar. 2016, JapaneseWhole-tree pressure-volume法によるスギの樹体内貯留水の測定Poster presentation
- 日本森林学会大会学術講演集, Mar. 2015, Japaneseミズナラとプナの林冠木における道管形成および個葉光合成の季節変化とシンクソースバランス
- 第126回日本森林学会大会, Mar. 2015, Japanese最大樹高に達した異樹齢アカマツにおける葉の生理特性の比較Poster presentation
- 第126回日本森林学会大会, Mar. 2015, Japaneseミズナラとブナの林冠木における道管形成および個葉光合成の季節変化とシンクソースバランスPoster presentation
- 日本生態学会第62回全国大会, Mar. 2015, Japanese樹上の世界に魅せられて－針葉樹の高木・老木における生理生態学的研究Nominated symposium
- The 1st International Conference on Urban Tree Diversity, Jun. 2014, EnglishDoes adjacent late-successional forest prevent plagiosere of fragmented and abandoned secondary forest in sub-urban Japan?Oral presentation
- 第125回日本森林学会大会, Mar. 2014, Japanese樹冠内の高さにともなうヒノキ鱗片葉の形態変化Poster presentation
- 第125回日本森林学会大会, Mar. 2014, Japanese種多様性を継承するlegacy treeとしてのヤクスギ老齢木の重要性Poster presentation
- 日本生態学会第61回全国大会, Mar. 2014, Japaneseヤクスギ針広混交林における着生植物群落の成立要因Poster presentation
- 日本生態学会第61回全国大会, Mar. 2014, Japanese自然林再生を目的とした緑化地における植生遷移Poster presentation
- 日本生態学会第61回全国大会, 2014, Japanese秋田スギの梢端葉の水ストレスは貯水機能によって改善される？Poster presentation
- The 8th Pacific Regional Wood Anatomy Conference, Nov. 2013, EnglishLeaf anatomy reflects vertical change in water-relations characteristics in the crown of tall Cryptomeria japonica trees.Poster presentation
- 第63回日本木材学会大会, Mar. 2013, Japaneseセコイアメスギの葉には、高さにともなう水ストレスの影響を緩和する機能があるか？Poster presentation
- 第124回日本森林学会大会, Mar. 2013, Japanese壮齢ヒノキ人工林の生態系機能に及ぼす強度間伐の影響Poster presentation
- 日本生態学会第60回全国大会, Mar. 2013, Japanese高木の樹冠における水ストレスと葉の水分生理特性：樹高100 mのセコイアメスギにみられる調節メカニズムPublic symposium
- The Japanese Forest Society Congress, 2011, Japanese, THE JAPANESE FORESTRY SOCIETYMeasuring the three dimensional structure of forests: techniques and application
- TREE HEALTH RESEARCH SOCIETY, JAPAN
- THE JAPAN WOOD RESEARCH SOCIETY
- THE ECOLOGICAL SOCIETY OF JAPAN
- THE JAPANESE FOREST SOCIETY
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), The University of Tokyo, 01 Apr. 2024 - 31 Mar. 2027Functional biogeography in Japanese cedar
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Kyushu University, 01 Apr. 2022 - 31 Mar. 2026Impact of beech water and nutrient stress induced by understory degradation on soil biodiversity and ecosystem function
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Early-Career Scientists, Kobe University, 01 Apr. 2022 - 31 Mar. 2026, Principal investigatorForest canopy ecology study focusing on epiphytic plant communities on large old trees
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Forest Research and Management Organization, 01 Apr. 2021 - 31 Mar. 2025, CoinvestigatorTowards predicting dynamics of tropical forest ecosystem based on changes in local resource environments and functional traits with tree ontogeny
- 科学技術振興機構, PM研修第二ステージFS研究, Jan. 2023 - Oct. 2024, Coinvestigator循環型社会を目指して里山資源の流通を創出する
- 日本学術振興会, 科学研究費助成事業, 国際共同研究加速基金(国際共同研究強化(B)), 京都大学, 07 Oct. 2021 - 31 Mar. 2024Fertilization effects on atmospheric methane uptake by a rubber tree plantation in Thailand: a direct microbial inhibition or an indirect stimulation by higher tree water use?The proposal has been adopted in November 2021 and we have immediately started discussion through both on-line and face meeting for the implementation of the research project and to define precisely the protocols of the different activities that are planned for the next two years. We have started purchasing the equipment’s which will be used in continuously in Thailand during the project and prepared administrative paper works. The PI travelled to Thailand for one week on another budget, visited the field site and laboratory facilities and met with all Thai partners to prepare for the implementation of the research and agree on the degree of involvement of Thai partners and their responsibilities in the project.
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Challenging Research (Exploratory), Kobe University, 09 Jul. 2021 - 31 Mar. 2024New interpretation of trees' strategies on the water conduction本研究の目的は、樹幹における通水停止と通水回復過程において、樹体内で起こっている現象を生理学および解剖学的手法によって解明することである。本年度は、①エンボリズムによる通水停止、②通水組織へ水（木部樹液）の再流入および通水の再開について、生立木における非破壊的な計測を行った。 通水停止と回復の日変化および長期変動、季節的・環境的な違いについては、Acoustic Emission法（AE法）および熱流束計、樹液流速計の値から明らかにできた。シマトネリコやクスノキの樹幹では、日照のある時間帯に継続してAEの発生が記録された。日照によって蒸散量が増えて樹液流速度が増加する。そのため、樹液にかかる張力（tension)の増加によってエンボリズムが発生しやすく、通導組織の排水が頻繁に起こったと推察した。AE数と同様に、熱流束の値（樹幹外から内方への熱の移動）は日照と共に増加が認められた。つまり、日中に外気温が上昇しても、樹幹内には低温の地中の水が上昇することにより、樹幹外から内方への熱移動の値が大きくなったと言える。曇天の日に瞬間的な日照があった時間帯に、AE数と熱流束の値が増大する現象を確認した。また、夜間に大気飽差の値が瞬間的に上昇した際にもAE発生が認められ、夜間にも蒸散が起こって木部樹液が動くことがあるという新たな知見を得た。このような傾向は、6-10月の計測期間を通して確認され、日中の気温が高い夏季の期間では特に明瞭に確認できた。
- 日本学術振興会, 科学研究費助成事業, 基盤研究(B), 東京大学, 01 Apr. 2021 - 31 Mar. 2024, Coinvestigator炭素分配戦略の視点から明らかにする天然スギ機能形質の地理変異スギは日本の森林で最もバイオマスの大きい樹種であり、全国に分布し森林面積の約20％を占めている。すなわちスギという樹種が日本の温帯林生態系の骨格構造を形成していると言っても過言ではない。近年、日本各地に分布する天然スギ集団が遺伝的に分化しているだけでなく、根浸出物や二次代謝物質などの機能形質にも大きな違いがあることが明らかになりつつある。しかしながら、機能形質の地理変異をもたらした要因や形質間の相互関係、更にはそれらの生態系機能への影響はほとんど明らかにされていない。 本研究は全国14集団の天然スギを対象に、複数の共通圃場での比較実験により機能形質の地理変異を詳細に調べ、炭素の配分を基軸としてその機能間関係を明らかにするとともに、降雨遮断・付加実験などによって、異なるスギ集団がCa動態や水循環を中心とする生態系機能に及ぼす潜在的影響の違いを明らかにする。 本課題では炭素分配を基軸として成長と防御、水利用様式などの機能的連関を明らかにする。繁殖への投資の変異も林冠木では重要な要素と考えられるが、幼木を対象にすれば除外することが可能である。川渡、新潟、筑波、熊本の共通圃場には14集団のエコタイプ個体が十分な反復を持って生育し、樹高2-4m程度となっている。ここで共通してみられる機能形質の違いは自然選択による局所適応を反映していると考えられる。 本研究では1）根からの浸出物放出量、2) BVOCの成分と放出量、3)葉のCaやリン（P）、窒素（N）を始め二次代謝物質など様々な化学的成分、4)光合成・蒸散における水利用特性、などの形質や機能の解析を数多くの個体を用いて行う。異なった環境下にある複数の共通圃場での結果を比較することで機能形質の反応基準（遺伝-環境交互作用）も明確にする。
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Kyoto University, 01 Apr. 2021 - 31 Mar. 2024, CoinvestigatorEstimation of sporadic CH4 emissions from a riparian wetland in responding to heave rain events
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Kobe University, 01 Apr. 2020 - 31 Mar. 2024, CoinvestigatorEvaluating physiological plasticity of trees to climate change using functional trait variation of xylem anatomy(1)宮崎大学演習林のスギクローン試験地において、スギ品種ごとの肥大成長速度、木部組織および水分通道の違いについて、木部資料の採取および測定機器の設置によって調査した。 (2)スギの物質生産に遺伝および環境要因が及ぼす影響を明らかにするために，複数の地域に設置された共通圃場において，品種による生産量，窒素利用，成長様式などの違いを定量 化する。 (3)成長特性の異なるスギ２系統の形成層帯で発現する遺伝子群の季節変化を把握するため、２系統４個体ずつから採取した組織についてRNA-seqを行った。 (4)愛媛大学農学部附属演習林において、スギ品種ごとの年輪試料採取を行い、安定同位体比測定のための試料調整を行った。 (5)鹿児島大学高隈演習林にて、スギ6品種の細根形質を調べたところ、細根形質の品種間差を確認したが、斜面位置にともなう細根形質の順応的変化は検出されなかった。
- 公益財団法人 市村清新技術財団, 第32回（令和5年度）植物研究助成, Apr. 2023 - Mar. 2024, Principal investigatorクロマツにおける日常的な蒸散活動に対する幹および葉の貯留水利用特性
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), University of Tsukuba, 01 Apr. 2020 - 31 Mar. 2023, CoinvestigatorEffects of tree cutting on plant and animal communities in forest canopy: implication from old-growth Yakusugi forest in Yakushima Island本研究の目的は、屋久島のヤクスギ林を対象として、林冠生態系の生物多様性の特徴とそれが維持されるのに必要な物質の動態を調査し、これらが森林伐採などの人為的攪乱によってどのように変化するのかを明らかにすることである。林冠は、生物多様性の高い空間として知られているが、人がアプローチしづらいため、科学的なデータが不足している。申請者らは、木登り技術を利用し、ヤクスギの巨木の林冠生態系について詳細な調査を行いたいと考えている。2020-2021年度は、新型コロナウイルス感染症の拡大により、現地調査やサンプル採集などを予定どおり実施することが困難であった。しかし、感染者数が比較的低く抑えられていた時期に、調査地を訪れることができ、ヤクスギの樹上の生物群集について調査を実施することができた。具体的には、調査対象とするヤクスギ個体に登攀し、林冠に堆積した落葉や土壌を採集した。採集は、1個体につき、高さの異なる2地点からとし、林冠に着生する植物などへの影響がなるべく出ない場所を選ぶこととした。採集したサンプルを対象として、ツルグレン法により、土壌動物の抽出を行った。抽出した土壌動物群集はエタノールに固定し、DNAを抽出した後、ミトコンドリアDNAのシトクロームオキシダーゼサブユニットI（COI）領域を対象としてDNAメタバーコーディング解析を実施した。その結果、無脊椎動物に由来する塩基配列（OTU；Operational taxonomic unit）を多数、検出することができた。これは、林冠に堆積した落ち葉や土壌をすみかとして、多様な生物が生息していることを示唆している。また、調査対象木の樹齢が比較的若い個体であっても、採集箇所によっては多様な土壌動物が生息していることが明らかとなった。
- ⼀般社団法⼈ヤンマー資源循環⽀援機構, 第8回（2021年度）助成事業, Apr. 2021 - Mar. 2023, Principal investigator気候変動がスギ⼈⼯林の炭素蓄積や⽔循環に及ぼす影響評価
- 公益財団法人 市村清新技術財団, 第30回（令和3年度）植物研究助成, Apr. 2021 - Sep. 2022, Principal investigatorクロマツ高木における日常的な蒸散活動に対する幹の貯留水利用の可能性
- 公益財団法人 日本生命財団, 2022年度日本生命財団 環境問題 若手研究・奨励研究助成, Oct. 2020 - Mar. 2022, Principal investigator巨樹上の着生植物群集に着目した林冠生態学的研究
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for JSPS Fellows, Kyoto University, 26 Apr. 2017 - 31 Mar. 2020, Principal investigatorElucidation of hydraulic adaptation in tall trees: focused on fuction and roll of tissue contributed to water transport and storage.本研究は、高木や高齢木の特徴ある樹種グループを対象に、高所への新規給水システムの実態把握や枝葉の貯水・通水機能の基盤となる組織構造とその役割の発見を通して、森林生態系を構築する樹木の水分生理学的適応様式を解明することを目標としている。 本年度は、昨年度に引き続き半島マレーシアパソ森林保護区内で隣接して生育する樹高40 mほどのDipterocarpus sablamellatus（DIPTSU）および樹高35 mほどのPtychopyxis caput-medusae（PTYCCA）について、水分生理特性や解剖特性等を測定した。また、幹下部および上部にデンドロメータを設置して、幹直径の放射方向の日変化の観測を始めた。さらに、タイムラプスカメラを樹冠に設置し、展葉・落葉のフェノロジー観測を始めた。 また、特徴ある樹種グループの対象として日本の森林限界域に生育する樹木の水分生理学的適応様式を明らかにするために、長野県の標高2500 m地点に生育する落葉広葉樹(ナナカマド、ダケカンバ)および常緑針葉樹（オオシラビソ、ハイマツ）4樹種について、夏季の水利用特性を評価した。その結果、各樹種ごとの光合成特性や水分生理特性が明らかとなった。なかでも森林限界以上の標高でも生育できるハイマツは、失水に強い葉を持ち、また高い通水コンダクタンスや水ポテンシャルによる駆動力から蒸散が維持されていた。各種の水利用特性は、山岳域における高ストレス環境下でも生育できる適応様式の一つと考えられた。 また、高木種ヒノキを対象に、滋賀県の桐生試験地に生育する60年生および100年生のヒノキ個体の幹の下部と梢端付近に、樹液流センサーおよびサイクロメーターを設置し、幹の貯留水に着目した通水特性の評価をおこなった。その結果、両樹齢ともに、日中の幹貯留水の利用が示唆された。樹齢間比較を行うべく、継続して観測を続けている。Competitive research funding
- 芦生研究林基金, 芦生研究林公募研究, Sep. 2019 - Mar. 2020, Principal investigator芦生研究林内の着生植物の林冠生態学的研究
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Kobe University, 01 Apr. 2016 - 31 Mar. 2019, CoinvestigatorWater-stressed and temporally embolized xylem recovered water conduction by the water supply via parenchyma cells in Cinnamomum camphora, or via narrow vessels in a liana species, Wisteria japonica. The rehydration system will contribute the drought resistance of these species. The transfer of substances between parenchyma and water conduits was demonstrated by the injection of living tissue with cesium solution. Averaged vessel diameter near the base of aged C. camphora was larger than that at the top of trees. Large vessels efficiently transport water to a whole tree. On the other hand, at the upper part, the wider latewood with narrow vessels will physically strengthen the stem. Water content of leaves of Cryptomeria japonica was higher in the upper shoots. Near-infrared spectroscopy with a mobile apparatus enabled the measurement of pigment concentration ascribable to the differences in mesophyll structure.
- 関西自然保護機構, 2018年度研究助成, Jun. 2018 - Dec. 2018, Principal investigator芦生研究林内保存木の着生植物群集の保全生態学的研究Competitive research funding
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Research Activity start-up, Grant-in-Aid for Research Activity start-up, Kyoto University, 26 Aug. 2016 - 31 Mar. 2018, Principal investigator高木および高齢木の水分生理学的適応様式の解明：貯水・通水機能の組織と役割従来、樹木は高木になるほど根から梢端までの水輸送が物理的に困難となり、梢端部は慢性的な水不足に陥りやすいと考えられてきた。しかし近年、いくつかの針葉樹高木種において梢端部ほど葉の貯水能が高くなることが明らかとなり、水輸送の困難さが補償されていることが示唆されている（Ishii et al. 2014; Azuma et al.2016；Chin and sillett. 2016）。 東南アジア熱帯雨林には突出木が出現するが、マレーシアのパソ森林保護区内に生育する樹高40mほどのフタバガキ科Dipterocarpus sublamellatusには、同一林冠樹種とは異なる高所での特有の給水システムの存在が示唆されていた（福井ら2007）。D. sublamellatusの葉はふくらんだ葉柄をもつことから、蒸散や光合成など水分要求の高い葉に近い場所での貯水・給水システムの可能性を推測し、葉の水分生理学的評価および組織構造の観察を行った。 その結果、D. sublamellatusの葉は高い貯水能を示し、水ポテンシャルは枝では夕方にかけて低下したものの、葉では低下しなかった。また、葉柄の含水比は1日を通して葉身よりも高かった。このことは、D. sublamellatusの葉柄が貯水タンクとなって葉における蒸散などの水分要求度に応じた一時的なインバランスを補償しており、高所の葉への水輸送にかかる負荷を緩和する役割をもつことを示唆している。一方で、幹の木部貯留水の寄与はみられなかった。葉柄の組織構造は皮層が厚く、これが外観におけるふくらみを形成しており、葉柄の高い含水比に寄与していると考えられる。これらの研究成果によって、熱帯高木種D. sublamellatusに特有な高所における給水システムの実態が明らかとなってきた。
- 平成29年度花博記念協会助成金事業, Apr. 2017 - Mar. 2018, Principal investigator芦生研究林内保存木の着生植物群集の保全生物学的研究Competitive research funding
- 平成28年度京都大学研究連携基盤次世代研究者支援事業, Dec. 2016 - Mar. 2017, Principal investigator植物組織の化学分析および構造解析に関する研究Competitive research funding
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for JSPS Fellows, Grant-in-Aid for JSPS Fellows, Kobe University, 01 Apr. 2013 - 31 Mar. 2016, Principal investigator針葉樹の樹高成長を規定する生理学的要因の解明高木の樹高成長は既往の理論的研究から樹冠上部の水ストレスが主要因となり制限されると考えられてきたが、申請者は樹高世界一のセコイアメスギの高所の葉における水ストレスへの適応と樹冠内の葉の水分特性の恒常性を明らかにし、高木の最大樹高の決定機構として「樹冠内水分恒常性仮説」をたてた。これが高木種に普遍的にあてはまるかを検証するため、樹高50mの秋田スギでも樹冠内の様々な高さの葉について形態特性・水分特性・組織構造を測定した結果、同様の樹冠内水分恒常性がみられた。さらに、高所の葉の貯水機能が高くなるメカニズムには、針葉樹に特有のTransfusion組織が日中の水分供給源および再水和時の貯水スペースとして寄与することが示唆された。ヒノキ科高木種においては、高所の葉は根からの吸水よりも貯水性を優先した組織構造の変化によって樹冠内の葉の水分恒常性が維持されることが考えられる（Azuma et al. 2015）。また、葉内の水分生理特性や貯水機構をさらに明らかにするため、葉内の水の物理化学特性に着目して定量化・可視化する技術研究をおこなった。秋田スギの葉の横断面切片を、顕微赤外分光法により葉の内部の化学特性を可視化する手法の検証から取り組み、水分や糖類の定量的データを葉横断切片の分布とあわせて二次元的に可視化することができた。また、スペクトル解析からは葉の水分保持メカニズムの一因として多糖類が寄与する作業仮説が得られた（Azuma et al. in review）。また、樹体全体を用いて作成したWhole-tree pressure-volume（WT-P-V）曲線から樹体内貯留量を求めるため、WT-P-V曲線とシュートP-V曲線の水分特性値を比較した。その結果、10年生スギ個体においては、木部ポテンシャルの低下にともない消失した樹体内貯留水のうち約90%が葉の貯留水であることが試算され、早朝時の個体の水不足の緩和に大きく寄与していることが示唆された。