Papers - SUZUKI Kojiro
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Growth of Castanopsis sieboldii and Cinnamomum camphora saplings under different soil physical properties with mixing soil amendments. Reviewed International coauthorship
Kako Matsunaga, Haruka Ishikawa, Ryosuke Atsukawa, Yumiko Kanazawa, Satoru Tanaka, Kojiro Suzuki, and Ian D. Rotherham
Arboriculture & Urban Forestry 51 ( 2 ) 10 - 127 2025.03
Language：English Publishing type：Research paper (scientific journal) Publisher：International Society of Arboriculture
Background: Urban areas, many located in lowlands, are often characterised by poor drainage and compacted soil and this can have
an impact on the growth of urban trees. Castanopsis sieboldii and Cinnamomum camphora are 2 evergreen tree species distributed throughout
southern Japan. Many of these trees are planted in urban areas and their suburbs, and others grow naturally. The differences between these 2
species in their response to soil physical conditions, particularly those towards waterlogging and low aeration conditions, have not previously
been studied. Methods: In this study, we analysed and compared the tolerance of Castanopsis spp. and Cinnamomum spp. to stagnant soil water
conditions and investigated the effects of soil quality improvement using obsidian perlite to increase air content in soil under stagnant and
drained water conditions on the growth of these plants in pot experiments. In the study, Castanopsis and Cinnamomum plants were grown on
sand alone or mixed with obsidian perlite, and these were subjected to stagnant or drained water treatments. Results: Under stagnant water conditions,
all young Castanopsis trees died within approximately 18 months. In contrast, only one young tree of Cinnamomum spp. grown on sand
died under stagnant water conditions, and those grown on sand mixed with obsidian perlite were still alive after 35 months under stagnant conditions.
Soil quality improvement using perlite increased the leaf abundance (numbers) in both species. Conclusions: Stagnant water with a
reduced soil air phase adversely affected Castanopsis spp. growth, but over the study period of 3 years Cinnamomum spp. was unaffected.
When selecting tree species for urban planting, the impact of localised soil conditions on tree physiology may be critical. -
Kako Matsunaga, Yumiko Kanazawa, Satoru Tanaka, Kojiro Suzuki
Tree and Forest Health 28 173 - 180 2024.08
Authorship：Last author Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Tree Health Research Society, Japan
The growth of sapling of Castanopsis sieboldii and Cinnamomum camphora under different soil physical properties were investigated for 41 months beginning April 2017. The study was carried out in pot experiments. Experimental pots (EP) consisted of expanded obsidian (40% by volume) mixed with mountain sand to create soil improvement plots while control pots (C) consisted of sand media. The results showed that the trunk base diameter of saplings in EP were larger compared to C in both species, especially C. sieboldii. There were no differences in the tree height between EP and C. The length of the primary branch in EP were larger than those of C in C. sieboldii, but there was no difference between EP and C in C. camphora. The total dry weight of EP was high compared to C in C. sieboldii and no differences between EP and C in C. camphora. The number of leaves in EP were significantly larger than C in C. sieboldii, but there were no differences between them in C. camphora. The effects of soil amendments varied by tree species, and soil physical properties at the time of planting were found to affect subsequent tree growth.
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Distribution of giant trees in the urban areas and western suburbs of Tokyo, Japan Reviewed International coauthorship International journal
Kako Matsunagaa Department of Landscape Architecture, Graduate School of Agro-Environmental Science, Tokyo University of Agriculture, Setagaya-Ku, Tokyo, Japan View further author information ,Ryosuke Atsukawa,Peng Xu,Nanako Killmann,Norma G. Medina,Satoru Tanaka,Kojiro Suzuki, Ian D. Rotherham
Arboricultural Journal 45 ( 4 ) 290 - 318 2023.08
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Taylor & Francis Online
Giant trees reflect site environmental conditions and to elucidate the distribution pattern of the giant trees, we investigated relationships between giant tree locations and landforms. On the basis of elevation, the landforms of Tokyo were divided into four types (lowland, plateau, hill, and mountain), and tree distribution patterns were divided into five groups, including three sub-types, with occurrence patterns of representative species [I: Frequently lowlands, often plateaux and mountain type (Machilus thunbergi); II: Frequently plateaux, often lowland, hill, or mountain type (Quercus acuta, Prunus speciosa, Taxodium distichum, Liriodendron tulipifera, Cedrus deodara, Aphananthe aspera, and Prunus × yedoensis “Somei-yoshino”) with two subtypes, II-1: Typically plateaux (Cinnamomum camphora, Castanopsis sieboldii, and Ginkgo biloba) and II-2: Frequently plateaux and hills (Zelkova serrata); III: Typically plateaux and hill type (Certis sinensis var. japonica, Torreya nucifera, Carpinus tschonoskii, Quercus myrsinifolia, and Quercus serrata) with one subtype, Frequently plateaux (Prunus jamasakura); IV: Mountains often with plateaux or hill type (Acer pictum subsp. mono, Aesculus turbinate, Abies firma, Cryptomeria japonica, and Cercidiphyllum japonicum); and V: Mountain-limited type (Castanea crenata, Pterocarya rhoifolia, and Fraxinus platypoda)]. Some giant trees, including Quercus crispula, Fagus japonica, Fagus crenata, and Tsuga sieboldii, were distributed in mountainous areas but not on plateaux, hills, or in lowlands. Some unique giant trees (Aphananthe aspera, Certis sinensis var. japonica, and Carpinus tschonoskii) are self-seeding in the wild and found in plateau areas but not mountainous or hilly areas. These results suggest that the distribution of giant trees is influenced by site ecological characteristics, tree physiology, and human management and land-use.
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Relationships between number of <i>Carabus insulicola</i> and soil surface hardness at Hayano Umegaya special conservation green area, Kawasaki city, Japan Reviewed
TATEISHI Genki, SUZUKI Kojiro, TANAKA Satoru
Journal of The Japanese Institute of Landscape Architecture 86 ( 5 ) 627 - 632 2023.03
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Institute of Landscape Architecture
<p>Lack of maintenance of the forest floor have increased abandoned Satoyama areas. Abandonment Satoyama influence not only number of plants but also insects. This study investigated reason of few numbers of <i>C. insulicola</i> at bamboo forest by looking at the condition of soil surface hardness by field surveys and room experiments. Firstly, we checked and classified by cluster analysis the relationships of vegetation types and numbers of <i>C. insulicola</i> populations by field surveys. The vegetation type survey was made in an abandoned forest floor and bamboo forest area by cutting mainly <i>Pleioblastus chino</i> and <i>Phyllostachys edulis.</i> Secondly, the soil surface hardness was measured in each vegetation types for three years. Thirdly, room experiments were done to see whether <i>C. insulicola</i> can or cannot dig under different soil surface hardness in all year round. The results showed that few numbers of <i>C. insulicola</i> at bamboo forest were influenced by soil surface hardness, because the soil surface hardness was higher at the bamboo forest than at the abandoned forest. In the experiments, <i>C. insulicola</i> were not able to dig and hibernate under soil surface hardness, 2kg/cm<sup>2</sup> in winter season.</p>
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Response of Native Plant, Ardisia pyramidalis (Cav.) Pers. to Alkaline Soil Condition for Use in Urban Landscape in Manila City, Metro Manila, Philippines Reviewed International coauthorship
Norma G. MEDINA, Nanako KILLMANN, Satoru TANAKA and Kojiro SUZUKI
Journal of agriculture science, Tokyo University of Agriculture 2023.01
Authorship：Last author Language：English Publishing type：Research paper (bulletin of university, research institution)
Ardisia pyramidalis (Cav.) Pers. is an evergreen tree and native species found in the Philippines with conspicuous flowers, edible leaves and medicinal values. Though rarely seen and commonly grown in nurseries, it is one of the native species that has potential for use in the urban environment. One of the challenges of enriching biodiversity in the urban area is the establishment of native plant species able to cope with harsh soil condition like increasing soil pH that has strong impact on plant growth. Field survey showed that soil in urban area has pH more than 7.0 or sometimes over 8.0 while soil where Ardisia naturally grows showed acidic ranging from 4.1-6.2. Planted Ardisia was growing well at soil pH 6.0-7.5. Thus, experiments to evaluate the tolerance reaction of A. pyramidalis to alkaline soil were conducted in Laguna Philippines from October 2020 to December 2021. Seedlings were grown in pots with 8-kg soil with varying amount of lime (Ca (OH)2). The results showed survival of plants at soil pH 7.5-7.7. At soil pH ≥8.3, the plants quickly defoliated but produce new leaves four to five months after treatments. Alkaline soil has significant effect on the number of leaves, tree height and leaf size of A. pyramidalis. But even beyond the optimum soil pH range for most plants, growth performance of Ardisia indicated that it is sensitive to changes in pH and has a wide range of pH adaptability. Deeper understanding of soil characteristics is crucial to sustain good health condition of the tree in urban landscape.
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Effect of cutting <i>Pleioblastus chino</i> (Franch. et Sav.) Makino on the seed germination and growth of seedlings of two <i>Callicarpa</i> species Reviewed
NAKAJIMA Hiroaki, MORIYAMA Sodai, TANAKA Satoru, SUZUKI Kojiro
Journal of the Japanese Society of Revegetation Technology 48 ( 1 ) 56 - 61 2022.08
Language：Japanese Publisher：JAPANESE SOCIETY OF REVEGETATION TECHNOLOGY
<p>In abandoned secondary forests, <i>Pleioblastus chino</i> can grow in an unregulated manner and suppress the growth of the herbaceous layer. Two <i>Callicarpa</i> species, <i>C. japonica</i> and <i>C. mollis</i> are constituents of the shrub layer in secondary forests. This study was conducted to investigate the effects of cutting <i>P. chino</i> in every summer on the seed germination and survival rate of seedlings of each species. As a result of seed germination experiments in the laboratory and in the secondary forest, it was found that the germination rate was high under light conditions just after collection and that was improved even under dark conditions at low temperature by wet storage for 6 months. The survival rate of each species was higher in the cutting <i>P. chino</i> plot than in the non-cutting plot.</p>
DOI： 10.7211/jjsrt.48.56
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Relationship between the greenspace area and number of plant species in the urban area of Yokohama, Japan Reviewed
Nanako Killmann, Norma G. Medina, Kako Matsunaga, Kojiro Suzuki, and Satoru Tanaka
ECO-HABITAT:JISE Research 28 ( 1 ) 2022.06
Language：English Publishing type：Research paper (scientific journal)
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Influence of stagnation on the growth of <i>Castanopsis sieboldii</i> and <i>C. cuspidata</i> seedlings under different temperature conditions
Matsunaga Kako, Suzuki Kojiro
Tree and Forest Health 26 ( 2 ) 81 - 82 2022.04
Language：Japanese Publishing type：Research paper (conference, symposium, etc.) Publisher：Tree Health Research Society, Japan
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Characteristics of urban greenspaces based on analysis of woody plants in Yokohama City, Japan Reviewed International coauthorship International journal
Nanako Killmann, Fumitaka Nishino, Kojiro Suzuki, Ian D. Rotherham
Landscape and Ecological Engineering 18 ( 2 ) 221 - 238 2022.04
Language：English Publishing type：Research paper (scientific journal)
Urban greenspaces are public spaces, fulfilling multiple city functions, such as improvement of public health. They are also ecosystems which provide biodiversity as part of the green infrastructure. To evaluate greenspaces as ecosystems, seventeen urban greenspaces in Yokohama, Japan, were selected to conduct surveys of flora and construct a vegetation table. The pre-sent study investigated the number of woody plant species; their growth form (tree, shrub, or liana); the ratio of evergreen to deciduous plants; and whether plant species were native, exotic, wild, or planted. The greenspaces were compared with the control area, Enkaizan, a suburban greenspace within Yokohama and representative of Satoyama (a traditional landscape model with sustainable living space). The comparison used cluster analysis to match the correlation of identified species in each greenspace and split them into four groups: (1) natural, (2) quasi-natural, (3) quasi-artificial, and (4) artificial. The study found the natural greenspace group to have an intact hierarchical forest structure with trees, shrubs, and lianas; whereas artificial greenspaces missed either tree or shrub layers and had few lianas. The more artificial greenspaces had higher pro-portions of exotic and evergreen species.
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NAKAJIMA Hiroaki, KUNO Naoto, MASUDA Kaede, HIRANO Yukari, KAMEYAMA Yoshiaki, SUZUKI Kojiro
Journal of The Japanese Institute of Landscape Architecture 84 ( 5 ) 687 - 692 2021.03
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Institute of Landscape Architecture
<p>The evergreen perennial herb, <i>Asarum tamaense</i> (Aristolochiaceae), is an endangered species distributed across the Tama Hills in the Kanto region of Japan. In abandoned secondary forests, <i>Pleioblastus chino</i> can grow unregulated and suppress the growth of the herbaceous layer. This study investigated how cutting <i>P. chino</i> affects the growth and flowering of <i>A. tamaense</i> in an abandoned secondary forest. Two study areas (cutting and non-cutting) were defined in an area of the Tama Hills secondary forests that had been untouched for approximately 40 years. <i>P. chino</i> was cut with a sickle in only the cutting area during the summers of 2010 - 2018. Each April from 2015 to 2018, in both areas, the number of patches, leaves and flowers were counted in 30 quadrats, 5m × 5m at each quadrat, and the photosynthetically active radiation (PAR) and soil moisture content were checked. The cutting area had less the number of patches than the non-cutting area, and there were no differences in the patches increase rate over time between the areas. The number of leaves and flowers and the increase rate in the cutting area were higher; as the number of leaves increased, the number of flowers increased. PAR was also higher in the cutting area. These results suggest that cutting <i>P. chino</i> contributes the conservation of <i>A. tamaense.</i></p>
DOI： 10.5632/jila.84.687
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Landforms and distribution patterns of giant Castanopsis sieboldii trees in urban areas and western suburbs of Tokyo, Japan Reviewed International coauthorship
Tomotsugu Watanabe, Kako Matsunaga, Yumiko Kanazawa, Kojiro Suzuki, Ian D. Rotherham
Urban Forestry & Urban Greening 60 ( 126997 ) 2021.01
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal)
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栃木県小山市における思川桜の植付け後17年生の樹形変化 Reviewed
金澤 弓子, 鈴木 貢次郎
関東森林研究 72（1） 49 - 52 2021
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Effects of under-story Sasa removal and bamboo felling on the ground-beetle fauna in secondary forests in Tama Hills, in Japan
Kazumasa OURA, Kyoichi FUJII, Hiroaki NAKAJIMA, Kojiro SUZUKI
Journal of the Japanese Institute of Landscape Architecture 83 ( 5 ) 743 - 748 2020.05
Language：English Publishing type：Research paper (scientific journal)
In secondary forests that have been abandoned, clear-cutting bamboo and thinning increase the species diversity of forest
floor plants. However, the effects on ground beetles have not been sufficiently studied. In this study, we set up survey traps at four
areas: Sasa (Pleioblastus chino) mowing area, Sasa standing area, bamboo (Phyllostachys edulis) clear-cutting area, and bamboo
standing area in Tama hill, Kanagawa Prefecture, Japan. A total of 80 traps were set up to capture ground beetles: 10 traps in each
area with two replicates. The number of species was greater in the case of management in the Sasa mowing area and bamboo clearcutting area than in the case of no management in the Sasa standing area and bamboo standing area. In particular, the number of
ground beetles was higher in the Sasa mowing area than in the Sasa standing area, bamboo clear-cutting area, and bamboo standing
area. The ground beetles belonging to Pterididae were the most common, and the most common species were Carabus insulicola,
Synuchus cycloderu, and Pterostichus yoritomus. In particular, C. insulicola comprised over 90% of the total ground beetles
collected from the Sasa mowing area, suggesting that this beetle can be used as an indicator of biodiversity in an abandoned
secondary forest. -
Soil physical condition for growing Quercus salicina and Q. myrsinifolia
Yutaka Fujimura, Ryosuke Atsukawa, Kojiro Suzuki
Trees ans Forest Health 24 ( 2 ) 94 - 95 2020.04
Language：Japanese Publishing type：Research paper (conference, symposium, etc.) Publisher：Tree Health Research Society, Japan
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Effects of soil physical and chemical properties on the growth of Castanopsis sieboldii
Kako Matsunaga, Kaori Marubashi, Kojiro Suzuki
Trees ans Forest Health 24 ( 2 ) 128 - 129 2020.04
Language：Japanese Publishing type：Research paper (scientific journal)
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Effects of four fertilizers (nitrogen, phosphoric, potassium and lime) on the growth of Cinnamomum camphora
Ryosuke Atsukawa, Kaori Marubashi, YUmiko Kanazawa, Kojiro Suzuki
Trees ans Forest Health 24 ( 2 ) 118 - 119 2020.04
Language：Japanese Publishing type：Research paper (scientific journal)
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OURA Kazumasa, FUJII Kyoichi, NAKAJIMA Hiroaki, SUZUKI Kojiro
Journal of The Japanese Institute of Landscape Architecture 83 ( 5 ) 743 - 748 2020.03
Language：Japanese Publisher：Japanese Institute of Landscape Architecture
<p>In secondary forests that have been abandoned, clear-cutting bamboo and thinning increase the species diversity of forest floor plants. However, the effects on ground beetles have not been sufficiently studied. In this study, we set up survey traps at four areas: Sasa (<i>Pleioblastus chino</i>) mowing area, Sasa standing area, bamboo (<i>Phyllostachys edulis</i>) clear-cutting area, and bamboo standing area in Tama hill, Kanagawa Prefecture, Japan. A total of 80 traps were set up to capture ground beetles: 10 traps in each area with two replicates. The number of species was greater in the case of management in the Sasa mowing area and bamboo clear-cutting area than in the case of no management in the Sasa standing area and bamboo standing area. In particular, the number of ground beetles was higher in the Sasa mowing area than in the Sasa standing area, bamboo clear-cutting area, and bamboo standing area. The ground beetles belonging to Pterididae were the most common, and the most common species were <i>Carabus insulicola, Synuchus cycloderu</i>, and <i>Pterostichus yoritomus</i>. In particular, <i>C. insulicola</i> comprised over 90% of the total ground beetles collected from the Sasa mowing area, suggesting that this beetle can be used as an indicator of biodiversity in an abandoned secondary forest.</p>
DOI： 10.5632/jila.83.743
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Seed germination characteristics of Maianthemum dilatatum (Wood) Nels. et Macbr. (Asparagaceae) Reviewed International journal
Hitomi Kawano, Yumiko Kanazawa, Kojiro Suzuki, Masashi Ohara
Plant Species Biology 35 ( 1 ) 1 - 11 2019.09
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal)
The seed germination characteristics of Maianthemum dilatatum were investigated in a laboratory experiment and the results compared with those of other species in the subfamily Asparagoideae, LILIACEAE (Engler's system).M. dilatatum seeds mature in late September to October in montane to subalpine areas across Japan. Germination percentages and rates were low for fresh seeds at 10 to 30C. Seeds cold stratified for 4 months or longer showed increased germination percentages and rates. The seeds lost germinability with decreasing moisture content. The seeds germinated well in dark conditions. The process of germination from the cotyledonary sheath/petiole breaking through the seed coat to the appearance of the first and second leaves was examined. After emergence of the cotyledonary sheath/petiole, a root emerged from it, and additional roots appeared after 1–2 months. The plumule emerged from the cotyledonary sheath/ petiole after the seedling had three roots. Seeds dispersed in autumn, and germinate slowly in the next spring after exposure to low temperature even though dark condition as buried seed. We compared the seed germination characteristics among species in the Asparagoideae or with other recent taxonomy, and found that seedlings of Paris erticillate and Trillium apetalon, which belong to Melanthiaceae, and Streptopus streptopoides Var. japonica and Clintonia udensis, which belong to Liliaceae (linear cotyledon), were different from Asparagaceae, showing a globose cotyledon in the APG II.
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Relationships between growing characteristics and soil chemistry of Castanopsis sieboldii.
Kaori Marubashi, Mizuki Nakamizo, Warabi Inoue, Kojiro Suzuki
Tree and Forest Health 23 ( 2 ) 102 - 103 2019.04
Authorship：Corresponding author Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Tree Health Reseach, Society, Japan
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Species, size, and location of `giant trees' in Tokyo's urban area and western suburbs Reviewed International coauthorship International journal
Xu Peng, Kotaro Tachikawa, Hiroaki Nakajima, Yumiko Kanazawa, Kojiro Suzuki, Christine Handley, and Ian D. Rotherham
Journal Arboricultural Journal 40 ( 4 ) 232 - 254 2018.10
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Taylor & Francis