Researcher Database

Toshiya Yoshida
Field Science Center for Northern Biosphere Forest Research Station Northern Forestry Research and Development Office
Professor

Researcher Profile and Settings

Affiliation

  • Field Science Center for Northern Biosphere Forest Research Station Northern Forestry Research and Development Office

Job Title

  • Professor

URL

Research funding number

  • 60312401

J-Global ID

Research Interests

  • 森林動態   ササ   個体群動態   針広混交林   環境要因   植生回復   森林伐採   影響評価   人工裸地   造林施業   掻き起し   地域間比較   資源管理モデル   植物種多様性   種多様性   北方林   物質循環   林学   森林流域   土壌学   河川水質   山火事撹乱   常緑性・落葉性   更新   野外操作実験   ブラックプルース   準水域   肥大成長   炭素   遷移   地域資源管理学   造林学   森林生態学   Regional Resources Management   Silviculture   Forest Ecology   

Research Areas

  • Environmental science/Agricultural science / Biological resource conservation
  • Life sciences / Forest science

Academic & Professional Experience

  • 2012 - Today Hokkaido University Field Science Center for Northern Biosphere
  • 2009 - 2012 Hokkaido University Field Science Center for Northern Biosphere
  • 2011 Hokkaido University
  • 2002 - 2009 - 北海道大学北方生物圏フィールド科学センター 助教
  • 1999 - 2002 北海道大学助手(農学部附属演習林) 助手
  • 1999 - 2001 Research Associate
  • 2001 - Research Associate,Field Science Center for Northern Biosphere, Hokkaido University

Education

  • 1995 - 1998  Niigata University  Graduate School of Science and Technology
  • 1993 - 1995  Niigata University
  • 1985 - 1989  Niigata University  Faculty of Agriculture

Association Memberships

  • 日本生態学会   日本森林学会   The Japanese Forestry SocietyThe Ecological Society of JapanInternational Association of Vegetation Science   

Research Activities

Published Papers

  • Haruka Yamazaki, Toshiya Yoshida
    Journal of Forest Research 23 (3) 166 - 172 1610-7403 2018/05/04 [Refereed][Not invited]
     
    We compared early establishment of B. maximowicziana, a commercially valuable tree species producing buried seeds, among the standard scarification and three alternative treatments in which surface soil was retained (soil replacing, screening, and plowing). We found the efficiencies of the soil retention for the seedling emergence were clearly different among the treatments the replacing and plowing caused significantly richer seedling emergence, whereas the screening resulted in lower emergence than the standard treatment. In total, the most abundant seedling emergence was estimated to have occurred in the case of higher soil water content with lower soil hardness. These seemed to be attributed to soil properties, induced differently by each treatment, and relatively high water demand characteristics of B. maxomowicziana. On the other hand, plowing showed low seedling density at the end of the second growing season despite its greater emergence, probably because of suppression from understory vegetation recovered from undisturbed root system. We conclude that replacing would be a best alternative for regeneration of B. maxomowicziana. The scarification treatments in which surface soil is retained can be evaluated to be positive or negative according to the site conditions, physiological characteristics of the target tree species, and recovery of other vegetation.
  • Tsuyoshi Sato, Haruka Yamazaki, Toshiya Yoshida
    Journal of Forest Research 22 (6) 336 - 342 1610-7403 2017/11/02 [Refereed][Not invited]
     
    Strong wind constitutes the major force behind disturbance of northern Japanese forests. Canopy gaps induced by disturbance are responsible for subsequent recovery of the stand (i.e. enhancement of growth and recruitment). There is also a possibility that a sudden change in stand structure, involving significant microclimatic alterations, results in further stand degradation. We therefore examined a hypothesis proposing that wind disturbance causes indirect and delayed negative effects on the demography of Abies sachalinensis, a dominant conifer species of northern Japanese natural mixed forests. Data for all trees in a 3-ha study stand with diameter at breast height ≥10 cm were recorded for over 10 years, including the period of severe wind disturbance induced by Typhoon Songda in 2004. We found that the total amount of dead A. sachalinensis in the post-disturbance period was equivalent to that in the wind disturbance. The mortality of the species was generally high in larger trees. Within 1–2 years immediately after the disturbance, dead trees frequently presented the uprooted form despite there being no record of strong winds, suggesting that the physical influence of the disturbance persisted. Moreover, these dead trees showed spatial association with trees in the surrounding trees that died due to strong wind. In contrast, most A. sachalinensis trees that died 3–8 years later showed growth reduction after the disturbance. We conclude that a strong wind disturbance can have long-term influence on the stand dynamics, during which the possible cause of tree deaths changes gradually from physical damage to physiological stress.
  • Toshiya Yoshida, Sayoko Naito, Misato Nagumo, Natsumi Hyodo, Taiki Inoue, Hiromitsu Umegane, Haruka Yamazaki, Hisashi Miya, Futoshi Nakamura
    SUSTAINABILITY 9 (11) 2071-1050 2017/11 [Refereed][Not invited]
     
    The objective of forest management has become broader, and it is essential to harmonize timber production with conservation of the forest ecosystem. Selection cutting is recognized as a major alternative of clear-cutting, because it can maintain the complexity and heterogeneity of a natural forest; however, its long-term evaluations are limited. This study compared various attributes of stand structures, which are indicators of biodiversity and ecosystem carbon stock between managed and unmanaged blocks (12.6 ha area in total) in a natural mixed forest in Hokkaido, the northernmost island of Japan. We found that 30 years' implementation of single-tree selection did not affect the volume, size structure, species diversity nor spatial distribution of overstory trees in the managed stands. Also, the total carbon stock in the managed stands was almost equal to that of the unmanaged stands. In contrast, several structural attributes and indicator elements that are significant for biodiversity (such as large-diameter live trees, dead trees, cavities, epiphytic bryophytes, and some avian guilds) showed marked decrease in the managed stands. We conclude that it is required to leave these structures and elements to some extent for deriving the merit of the management as an alternative silvicultural regime in the region.
  • Ippei Asada, Haruka Yamazaki, Toshiya Yoshida
    FOREST ECOLOGY AND MANAGEMENT 393 81 - 88 0378-1127 2017/06 [Refereed][Not invited]
     
    Spatial patterns have been a major topic regarding natural regeneration of oak species, but the effects may differ considerably in sites subjected to intense forestry practices, which greatly alter many aspects of site conditions. We examined the hypothesis that the regeneration of oak (Quercus crispula Blume) following scarification (displacement of inhibiting vegetation and surface soil using machinery) is enhanced at a certain distance from a conspecific overstory tree, depending on the stage of development. We conducted both field surveys in scarification sites with different stand ages (1-16 year-old) and a laboratory seeding experiment to clarify factors contributing to its early establishment. The results demonstrate that the spatial relationship between the regeneration of oak and the conspecific overstory tree at scarification sites changes considerably among stages of the establishment. In the initial stage (0-1 years after the scarification), a location beneath the crown provided favorable conditions, whereas at subsequent stages (2-4 years), the distance-dependent effects were unclear, until eventually (8-16 years) a location outside the crown became more favorable. The condition produced by the scarification was basically competition-free and resource-rich, but it can also be harsh for acorns and small seedlings, imposing a requirement for shading to moderate the environment in the initial stage. Such an effect of facilitation was found also in the later (sapling) stage via the existence of neighbors of the other regenerated fast-growing species. The current findings supported the effectivity of a shelter-wood system, in which the regeneration starts from shaded condition followed by a gap status created by a successive felling. The area away from the conspecific crown would have a potential if acorns are plentifully supplied (e.g. by direct seeding) and they withstand the initial negative factors at the initial stage of development. (C) 2017 Elsevier B.V. All rights reserved.
  • Takahiro Inoue, Karibu Fukuzawa, Tsunehiro Watanabe, Toshiya Yoshida, Hideaki Shibata
    ECOLOGICAL RESEARCH 32 (2) 227 - 241 0912-3814 2017/03 [Refereed][Not invited]
     
    Natural disturbances create spatial patterns of the ecosystem processes and functions in natural forests. However, how dynamics and the spatial structure of forests relate to soil nitrogen dynamics is not well understood. We examined the spatial relationship between the distributions of canopy and understory species, and soil nitrogen dynamics in a natural coniferous-broadleaved mixed forest with a dense understory of Sasa dwarf bamboo in northern Japan. The O horizon was thick where coniferous litter predominated, and it was thin where broadleaved litter predominated. The soil water content was low in areas with a thick O horizon and a high abundance of coniferous trees. The soil nitrate content was low where the soil water content was low, and the soil nitrate content increased linearly with increasing net nitrification potential. These results suggest that the soil nitrate content under the coniferous canopy was lower because of the low nitrification potential of soil microbes in soils with low water contents. The soil nitrate content and nitrification potential were higher in the canopy gap than under the canopy. Our results suggest that forest structure, specifically the thickness of the forest floor, significantly affects the spatial pattern of the soil water content, thereby creating a spatial pattern of soil nitrogen availability at a relatively small scale with flat topography. The higher nitrification potential under the canopy gap could pose a long-term risk of nitrate leaching because of the suppression of the natural regeneration of canopy species by dense Sasa dwarf bamboo in this forest ecosystem.
  • Shigeru Niwa, Ayu Toyota, Toshio Kishimoto, Kji Sasakawa, Shin Abe, Takeshi Chishima, Motoki Higa, Tsutom Hiura, Kosuke Homma, Daisuke Hoshino, Hideyuki Ida, Naoto Kamata, Yohei Kaneko, Motohiro Kawanishi, Kazutaka Kobayashi, Kaname Kubota, Koichiro Kuraji, Takashi Masaki, Kaoru Niiyama, Mahoko Noguchi, Haruto Nomiya, Satoshi Saito, Michinori Sakimoto, Hitoshi Sakio, Shigeho Sato, Mitsue Shibata, Atsushi Takashima, Hiroshi Tanaka, Naoaki Tashiro, Naoko Tokuchi, Hisahiro Torikai, Toshiya Yoshida
    ECOLOGICAL RESEARCH 31 (5) 607 - 608 0912-3814 2016/09 [Refereed][Not invited]
     
    This data paper reports census data of ground-dwelling beetle and other fauna of the forest floor environment; collections were made from a network of 22 forest sites in Japan. To our knowledge, this represents the largest dataset for long-term monitoring of a ground-dwelling beetle community and other taxa in a ground environment in forests, which covers a broad climatic range in the temperate zone and is freely available. The network forms part of the Monitoring Sites 1000 Project launched by the Ministry of the Environment, Japan. It covers subalpine, cool- and warm-temperate and subtropical climatic zones and the four major forest types of Japan. Thirty-three permanent plots usually 1 ha in size were established in old-growth, secondary natural and a few plantation forests. Censuses of the ground-dwelling beetle community were conducted using pitfall trapping and forest floor environment monitoring every year from 2004 to the present. During the initial 9 years of the census (2004-2012), 59,762 beetle individuals (including 3182 larvae) of more than 314 species were recorded. This dataset includes taxonomy and biomass of each beetle individual and each taxonomic group of other invertebrates coincidently captured in pitfall trapping. The dataset also includes data related to ground coverage by forest floor vegetation, dry mass of the accumulated organic litter layer, and carbon and nitrogen contents and cellulose decomposition rate in organic layer and surface mineral soil. The data could be used to investigate geographical patterns and intra- and inter-annual dynamics of individual body mass, populations and community structures of ground-dwelling beetles, and their relationships with the forest floor environment. Furthermore, the data could be analyzed with other open datasets related to tree community dynamics and litter fall continuously measured in the same study plots. This dataset also provides information related to the distribution and average body mass of each beetle species.
  • 吉田俊也
    北方林業 67 (1) 29‐32  0388-8045 2016/04/01 [Not refereed][Not invited]
  • 田村太壱, 加藤顕, 小花和宏之, 吉田俊也
    日本緑化工学会誌 41 (1) 163 - 168 0916-7439 2015/08/31 [Not refereed][Not invited]
  • Takeshi Motohka, Toshiya Yoshida, Hideaki Shibata, Takeo Tadono, Masanobu Shimada
    IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING 53 (4) 1683 - 1691 0196-2892 2015/04 [Refereed][Not invited]
     
    We tested the performance of the stereo observations of the Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) onboard the Advanced Land Observing Satellite (ALOS) in the mapping of forest aboveground biomass (AGB) in Japan. Digital canopy height models (DCHMs), which are differences between PRISM digital surface models and surveying-based digital terrain models (DTMs), were compared to in situ AGB measurements of several forest types (number of stands: 28; average stand size: 0.54 ha; stand size range: 0.25-3.00 ha). DCHM values exhibited a significant correlation with AGB (r = 0.66-0.87; five different DCHMs), and the root-mean-square error and bias of the regression model evaluated by the leave-one-out cross validation were 37.2-57.8 t/ha(22.1%-32.6%) and -0.11-1.89 t/ha, respectively. There was no saturation in the relationship between DCHM and AGB (AGB range: 19-332 t/ha). The correlations between DCHM and mean canopy height (r = 0.17-0.52) and between DCHM and Lorey's height (r = 0.26-0.66) were weaker than the correlation between DCHM and AGB. The PRISM AGB distribution estimated by the regression model was consistent with a tree density map produced from aerial photos. Comparison to Phased Array-type L-band Synthetic Aperture Radar (PALSAR) data showed that the PRISM DCHMs can estimate high AGB over the saturation level of PALSAR backscattering coefficient, i.e., 100-200 t/ha. The results described here demonstrate that the PRISM DCHMs are capable of wall-to-wall AGB estimation at 50-m resolution. This approach will be useful for improving the performance of satellite-based AGB estimation when an accurate DTM is available.
  • Takeshi Motohka, Toshiya Yoshida, Hideaki Shibata, Takeo Tadono, Masanobu Shimada
    IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING 53 (4) 1683 - 1691 0196-2892 2015/04 [Refereed][Not invited]
     
    We tested the performance of the stereo observations of the Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) onboard the Advanced Land Observing Satellite (ALOS) in the mapping of forest aboveground biomass (AGB) in Japan. Digital canopy height models (DCHMs), which are differences between PRISM digital surface models and surveying-based digital terrain models (DTMs), were compared to in situ AGB measurements of several forest types (number of stands: 28; average stand size: 0.54 ha; stand size range: 0.25-3.00 ha). DCHM values exhibited a significant correlation with AGB (r = 0.66-0.87; five different DCHMs), and the root-mean-square error and bias of the regression model evaluated by the leave-one-out cross validation were 37.2-57.8 t/ha(22.1%-32.6%) and -0.11-1.89 t/ha, respectively. There was no saturation in the relationship between DCHM and AGB (AGB range: 19-332 t/ha). The correlations between DCHM and mean canopy height (r = 0.17-0.52) and between DCHM and Lorey's height (r = 0.26-0.66) were weaker than the correlation between DCHM and AGB. The PRISM AGB distribution estimated by the regression model was consistent with a tree density map produced from aerial photos. Comparison to Phased Array-type L-band Synthetic Aperture Radar (PALSAR) data showed that the PRISM DCHMs can estimate high AGB over the saturation level of PALSAR backscattering coefficient, i.e., 100-200 t/ha. The results described here demonstrate that the PRISM DCHMs are capable of wall-to-wall AGB estimation at 50-m resolution. This approach will be useful for improving the performance of satellite-based AGB estimation when an accurate DTM is available.
  • 戸田求, 福澤加里部, 中村誠宏, 田中幹展, 吉田俊也, 柴田英昭, WANG Xin, 石田祐宣, 宮田理恵
    低温科学 73 21 - 29 1880-7593 2015/03/31 [Not refereed][Not invited]
  • 來住牧, 宮久史, 吉田俊也, 植村滋
    低温科学 73 125 - 132 1880-7593 2015/03/31 [Not refereed][Not invited]
  • Kentaro Takagi, Yasumichi Yone, Hiroyuki Takahashi, Rei Sakai, Hajime Hojyo, Tatsuya Kamiura, Mutsumi Nomura, Naishen Liang, Tatsuya Fukazawa, Hisashi Miya, Toshiya Yoshida, Kaichiro Sasa, Yasumi Fujinuma, Takeshi Murayama, Hiroyuki Oguma
    ECOLOGICAL INFORMATICS 26 (3) 54 - 60 1574-9541 2015/03 [Refereed][Not invited]
     
    Trees are recognized as a carbon reservoir, and precise and convenient methods for forest biomass estimation are required for adequate carbon management Airborne light detection and ranging (LiDAR) is considered to be one of the solutions for large-scale forest biomass evaluation. To clarify the relationship between mean canopy height determined by airborne LiDAR and forest timber volume and biomass of cool-temperate forests in northern Hokkaido, Japan, we conducted LiDAR observations covering the total area of the Teshio Experimental Forest (225 km(2)) of Hokkaido University and compared the results with ground surveys and previous studies. Timber volume and aboveground tree carbon content of the studied forest stands ranged from 101.43 to 480.40 m(3) ha(-1) and from 30.78 to 180.54 MgC ha-1, respectively. The LiDAR mean canopy height explained the variation among stands well (volume: r(2) = 0.80, RMSE = 55.04 m(3) ha(-1); aboveground tree carbon content: = 0.78, RMSE = 19.10 MgC ha(-1)) when one simple linear regression equation was used for all types (hardwood, coniferous, and mixed) of forest stands. The determination of a regression equation for each forest type did not improve the prediction power for hardwood (volume: r(2) = 0.84, RMSE = 62.66 m(3) ha(-1); aboveground tree carbon content: r(2) = 0.76, RMSE = 27.05 MgC ha(-1)) or coniferous forests (volume: r(2) = 0.75, RMSE = 51.07 m(3) ha(-1); aboveground tree carbon content: r(2) = 0.58, RMSE = 19.00 MgC ha(-1)). Thus, the combined regression equation that includes three forest types appears to be adequate for practical application to large-scale forest biomass estimation. (C) 2015 Elsevier B.V. All rights reserved.
  • Kentaro Takagi, Yasumichi Yone, Hiroyuki Takahashi, Rei Sakai, Hajime Hojyo, Tatsuya Kamiura, Mutsumi Nomura, Naishen Liang, Tatsuya Fukazawa, Hisashi Miya, Toshiya Yoshida, Kaichiro Sasa, Yasumi Fujinuma, Takeshi Murayama, Hiroyuki Oguma
    ECOLOGICAL INFORMATICS 26 54 - 60 1574-9541 2015/03 [Refereed][Not invited]
     
    Trees are recognized as a carbon reservoir, and precise and convenient methods for forest biomass estimation are required for adequate carbon management Airborne light detection and ranging (LiDAR) is considered to be one of the solutions for large-scale forest biomass evaluation. To clarify the relationship between mean canopy height determined by airborne LiDAR and forest timber volume and biomass of cool-temperate forests in northern Hokkaido, Japan, we conducted LiDAR observations covering the total area of the Teshio Experimental Forest (225 km(2)) of Hokkaido University and compared the results with ground surveys and previous studies. Timber volume and aboveground tree carbon content of the studied forest stands ranged from 101.43 to 480.40 m(3) ha(-1) and from 30.78 to 180.54 MgC ha-1, respectively. The LiDAR mean canopy height explained the variation among stands well (volume: r(2) = 0.80, RMSE = 55.04 m(3) ha(-1); aboveground tree carbon content: = 0.78, RMSE = 19.10 MgC ha(-1)) when one simple linear regression equation was used for all types (hardwood, coniferous, and mixed) of forest stands. The determination of a regression equation for each forest type did not improve the prediction power for hardwood (volume: r(2) = 0.84, RMSE = 62.66 m(3) ha(-1); aboveground tree carbon content: r(2) = 0.76, RMSE = 27.05 MgC ha(-1)) or coniferous forests (volume: r(2) = 0.75, RMSE = 51.07 m(3) ha(-1); aboveground tree carbon content: r(2) = 0.58, RMSE = 19.00 MgC ha(-1)). Thus, the combined regression equation that includes three forest types appears to be adequate for practical application to large-scale forest biomass estimation. (C) 2015 Elsevier B.V. All rights reserved.
  • Silvicultural alternatives to conventional even-aged forest management - what limits global adoption?"
    Puettmann, K.J, Wilson, S, Baker, S, Donoso, P, Droessler, L, Amente, G, Harvey, B.D, Knoke, T, Lu, Y, Nocentini, S, Putz, F.E, Yoshida, T, Bauhus, J
    Forest Ecosystems 2 8  2015 [Refereed][Not invited]
  • 加藤顕, 安藤祐樹, 吉田俊也, 梶原康司, 本多嘉明, 小林達明
    日本緑化工学会誌 40 (1) 136 - 141 0916-7439 2014/08/20 [Not refereed][Not invited]
  • 吉田俊也
    ランドスケープ研究 78 (2) 87 - 88 1340-8984 2014/07/31 [Not refereed][Not invited]
  • 加藤顕, 阿部葉月, 安藤祐樹, 吉田俊也
    ランドスケープ研究 78 (1) 54 - 55 1340-8984 2014/04/25 [Not refereed][Not invited]
  • Akira Yasuda, Toshiya Yoshida, Hisashi Miya, Brian D. Harvey
    JOURNAL OF FOREST RESEARCH 18 (5) 398 - 406 1341-6979 2013/10 [Refereed][Not invited]
     
    In uneven-aged conifer-broadleaved mixed forests in Hokkaido, northern Japan, single-tree selection cutting has been a common management practice since the early twentieth century. This practice is expected to produce timber without major changes in stand structure or tree species composition. The demographic response of forests to this practice has often been unexpected, and degradation of stand properties has been widely observed. We propose here a sustainable management regime of selection cutting, based on an individual-based forest dynamics simulation model, SORTIE-ND. Our simulations, based on demographic data from 15 long-term monitoring stands, suggest that selection cutting using a lower cutting intensity together with a longer rotation period and reduced removal of small trees and conifer species is more appropriate than traditional systems in terms of maintaining stand structure and tree species composition, as well as being profitable financially. Supplemental regeneration practices, which can counter accidental mortality incurred during harvesting operations, would also be necessary to ensure tree recruitment.
  • 吉田俊也
    北方林業 64 (11) 341-343  0388-8045 2012/11/01 [Not refereed][Not invited]
  • Satoshi N. Suzuki, Masae I. Ishihara, Masahiro Nakamura, Shin Abe, Tsutom Hiura, Kosuke Homma, Motoki Higa, Daisuke Hoshino, Kazuhiko Hoshizaki, Hideyuki Ida, Ken Ishida, Motohiro Kawanishi, Kazutaka Kobayashi, Koichiro Kuraji, Shigeo Kuramoto, Takashi Masaki, Kaoru Niiyama, Mahoko Noguchi, Haruto Nomiya, Satoshi Saito, Takeshi Sakai, Michinori Sakimoto, Hitoshi Sakio, Tamotsu Sato, Hirofumi Shibano, Mitsue Shibata, Maki Suzuki, Atsushi Takashima, Hiroshi Tanaka, Masahiro Takagi, Naoaki Tashiro, Naoko Tokuchi, Toshiya Yoshida, Yumiko Yoshida
    ECOLOGICAL RESEARCH 27 (6) 989 - 990 0912-3814 2012/11 [Refereed][Not invited]
  • 長谷川幹夫, 中島春樹, 吉田俊也
    植物地理・分類研究 59 (1) 31-34  0388-6212 2011/12/01 [Not refereed][Not invited]
  • 井上太樹, 南雲未智, 伊村智, 吉田俊也
    せん苔類研究 10 (6) 173-174  1343-0254 2011/11 [Not refereed][Not invited]
  • Masae I. Ishihara, Satoshi N. Suzuki, Masahiro Nakamura, Tsutomu Enoki, Akio Fujiwara, Tsutom Hiura, Kosuke Homma, Daisuke Hoshino, Kazuhiko Hoshizaki, Hideyuki Ida, Ken Ishida, Akira Itoh, Takayuki Kaneko, Kaname Kubota, Koichiro Kuraji, Shigeo Kuramoto, Akifumi Makita, Takashi Masaki, Kanji Namikawa, Kaoru Niiyama, Mahoko Noguchi, Haruto Nomiya, Tatsuhiro Ohkubo, Satoshi Saito, Takeshi Sakai, Michinori Sakimoto, Hitoshi Sakio, Hirofumi Shibano, Hisashi Sugita, Mitsuo Suzuki, Atsushi Takashima, Nobuyuki Tanaka, Naoaki Tashiro, Naoko Tokuchi, Toshiya Yoshida, Yumiko Yoshida
    ECOLOGICAL RESEARCH 26 (6) 1007 - 1008 0912-3814 2011/11 [Not refereed][Not invited]
     
    This data paper reports tree census data collected in a network of 34 forest sites in Japan. This is the largest forest data set freely available in Japan to date. The network is a part of the Monitoring Sites 1000 Project launched by the Ministry of the Environment, Japan. It covers subarctic to subtropical climate zones and the four major forest types in Japan. Forty-two permanent plots, usually 1 ha in size, were established in old-growth or secondary natural forests. Censuses of woody species a parts per thousand yen15 cm girth at breast height were conducted every year or once during 2004 to 2009. The data provide species abundance, survivorship and stem girth growth of 52,534 individuals of 334 tree and liana species. The censuses adopted common census protocol, which provide good opportunities for meta-analyses and comparative studies among forests. The data have been used for ecological studies as well as for the biodiversity reports published by the Ministry of the Environment.
  • Toshiya Yoshida, Mahoko Noguchi, Shigeru Uemura, Satoshi Yanaba, Hisashi Miya, Tsutom Hiura
    JOURNAL OF FOREST RESEARCH 16 (3) 215 - 222 1341-6979 2011/06 [Refereed][Not invited]
     
    Windthrow is recognized as an extremely significant disturbance in many forests. Its effects are increased by stand fragmentation, which exposes the stand to strong winds. In this study, we investigated the change in tree mortality in fragmented stands with the distance from the stand edge, in a conifer-broadleaved mixed forest in northern Japan. We set out experimental plots having three stand sizes (400, 1,600, 6,400 m 2) and examined the stand dynamics over 10 years. Tree mortality tended to be higher in smaller stands, although an effect of stand size was found only in the first 5 years of the study. Distance-dependent individual mortality was obvious in Abies sachalinensis, the most vulnerable major tree species, again in the first 5 years, suggesting that wind-risk management should emphasize the area within ca. 20 m from the stand edge. No distant-dependent effect was found, however, in the latter 5 years, in which there was a strong typhoon; tree deaths occurred throughout the stand (irrespective of distance within) as a result of this event. We conclude that the severity of wind can cause the features of wind-induced damage to differ; stand edge effects peculiar to a small forest are unlikely to occur with particularly strong winds, and the effect of fragmentation might therefore be clear only in weaker disturbances.
  • Floortje Vodde, Kalev Jogiste, Yasuhiro Kubota, Timo Kuuluvainen, Kajar Koester, Aljona Lukjanova, Marek Metslaid, Toshiya Yoshida
    JOURNAL OF FOREST RESEARCH 16 (3) 155 - 167 1341-6979 2011/06 [Refereed][Not invited]
     
    We reviewed studies dealing with regeneration under variable conditions in boreal and hemiboreal forests as affected by different microsite types by tree species functional groups. Generally, the importance of storm-induced microsites for regeneration dynamics in boreal forests depends on several factors: (1) distribution and type of microsites (generated by storm characteristics and stand conditions); (2) viable seed supply (stand history, species dispersal traits and status of surviving trees) and their species' life history strategy; (3) climatic and site conditions (pre-storm conditions and storm-induced changes); and (4) delayed storm effects, such as retarded falling of trees, favoured vegetation growth, etc. Studies acknowledging the significance of microsites were mostly related to intermediate or severe events, causing sufficient changes in resource levels and growth conditions, and influencing extrinsic factors such as frost heaving, erosion and browsing. Also, the dispersal traits of available tree species, including sprouting and response of surviving trees, such as canopy expansion, should be considered in evaluating microsite importance in individual cases. In intermediate to severe windstorm events, pioneer species are generally profiting most from the additional offer in microsites, requiring bare mineral soil and elevated locations for their establishment and growth. Under gap dynamics, shade-tolerant species benefit from dead wood and elevated locations as these offer safe sites in stands with abundant understorey vegetation.
  • Ahto Kangur, Toshiya Yoshida, Yasuhiro Kubota, Marek Metslaid
    JOURNAL OF FOREST RESEARCH 16 (3) 153 - 154 1341-6979 2011/06 [Refereed][Not invited]
  • Motomu Toda, Pasi Kolari, Taro Nakai, Yuji Kodama, Hideaki Shibata, Toshiya Yoshida, Shigeru Uemura, Akihiro Sumida, Kyoko Kato, Kiyomi Ono, Toshihiko Hara
    JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES 116 G02006-45  0148-0227 2011/04 [Refereed][Not invited]
     
    The effects of wind disturbance on forest dynamics and ecosystem CO2 exchange were examined in cool temperate forests of northern Japan during 2004-2008 using eddy covariance (EC) measurements. One site was a young, even-aged, monoculture, deciduous forest; the other was an uneven-aged mixed forest of evergreen and deciduous overstory tree species, including some over 200 years old. On 8 September 2004, a strong typhoon struck the forests, after which leaf and branch amounts decreased in young growth forest, but foliage showed little change in old growth forest. By 2006, foliage at the young-growth forest had recovered to the 2004 pretyphoon state. Average daily accumulated gross primary production (GPP(d)), terrestrial ecosystem respiration (TERd), and net ecosystem exchange (NEEd) were assessed for six growth stages annually. After the typhoon, large increases in GPP(d) were found during the growing stage of overstory tree species with high photosynthetic rates compared to that before the typhoon. Pronounced increases in GPP(d) and corresponding large reductions in NEEd were detected at the young-growth forest, indicating that NEEd was largely regulated by GPP(d) throughout the growing stages. Although EC measurements contain uncertainty, our continuous EC measurements revealed that interannual variability in meteorological variables and structural changes in foliage have only small impacts on GPP and NEE, while photosynthetic recovery of foliage from typhoon damage has high potential to increase GPP and enhance NEE as compared with those under nondamage conditions.
  • 清水池 義治, 神沼 公三郎, 佐藤 信, 吉田 俊也, 奈須 憲一郎, 三島 徳三
    地域と住民 : 道北地域研究所年報 名寄市立大学 0 (29) 73 - 88 0288-4917 2011/03 [Not refereed][Not invited]
  • 柴田英昭, 高木健太郎, 吉田俊也, 福澤加里部, 佐藤冬樹, 笹賀一郎
    Water science 日本治山治水協会 54 (6) 30 - 42 0039-4858 2011/02/01 [Not refereed][Not invited]
  • Keiichi Aoyama, Toshiya Yoshida, Akane Harada, Mahoko Noguchi, Hisashi Miya, Hideaki Shibata
    JOURNAL OF FOREST RESEARCH 16 (1) 35 - 45 1341-6979 2011/02 [Refereed][Not invited]
     
    To restore non-wooded stands dominated by dwarf bamboo species (Sasa kurilensis or S. senanensis) into forests, mechanical soil scarification has been applied in northern Japan since the 1960s. The treatment is followed both by natural regeneration and artificial planting. In this study, we quantified the total carbon stock (plants plus 0.3 m depth of soil) of these stands over 35-year age-sequences. The natural regeneration stands were gradually dominated by Betula ermanii. The carbon stock increased linearly to 215.1 +/- A 35.2 Mg C ha(-1) for a 37-year-old stand formerly dominated by S. kurilensis, and 181.1 +/- A 29.8 Mg C ha(-1) for a 34-year-old stand formerly dominated by S. senanensis. The latter was similar to that of a Picea glehnii plantation, formerly dominated by S. senanensis, with comparable stand age (160.3 +/- A 6.7 Mg C ha(-1) for 35-year-old stands). Although the carbon stock in plants quickly offset the untreated level, that in the soil remained depressed even in the older stands. This resulted in small differences in carbon stock of these stands with untreated dwarf bamboo stands. We conclude that natural regeneration following scarification could be a prime option for carbon sink management in the region. However, we should take a long rotation period (i.e., > 50 years) to ensure a carbon sink state. A potential of further improvements of the practice, including that reduce intensity of soil disturbance, was presented.
  • 吉田俊也
    北方林業 北方林業会 63 (1) 6 - 9 0388-8045 2011/01/01 [Not refereed][Not invited]
  • Hiromi Mizunaga, Takuo Nagaike, Toshiya Yoshida, Sauli Valkonen
    JOURNAL OF FOREST RESEARCH 15 (1) 1 - 2 1341-6979 2010/02 [Refereed][Not invited]
  • Ishihara M., Sakai T., Saito S., Sakio H., Sakimoto M., Shibano H., Sugita H., Suzuki M., Takagi M., Takashima A., Takyu M., Ishida K., Tashiro N., Tanaka N., Tokuchi N., Namikawa K., Niiyama K., Nishimura N., Noguchi M., Nomiya H., Hiura T., Fujiwara A., Ida H., Hoshino D., Homma K., Makita A., Masaki T., Yoshioka T., Yoshida T., Itoh A., Enoki T., Ohkubo T., Kaneko T., Kaneko N., Kuramoto S.
    JAPANESE JOURNAL OF ECOLOGY 日本生態学会暫定事務局 60 (1) 111 - 123 0021-5007 2010 [Not refereed][Not invited]
     
    モニタリングサイト1000は環境省生物多様性センターの事業であり、そのうち森林・草原調査では、樹木、地表徘徊性甲虫、鳥類を指標生物群として定め、2004年よりモニタリング調査を行っている。本稿では、コアサイト・準コアサイトで取られた樹木に関するデータ(毎木調査データ)が研究・教育・保全政策などに広く活用されるよう、その概要を紹介し、データの活用方法について提案する。
  • Toshiya Yoshida, Mahoko Noguchi
    LANDSCAPE AND ECOLOGICAL ENGINEERING 6 (1) 37 - 42 1860-1871 2010/01 [Refereed][Not invited]
     
    Previous studies have indicated that recruitment of Abies sachalinensis, a representative conifer species of northern Japan, decreased following single-tree selection harvesting in stands with dense dwarf bamboo understory. We tested the hypothesis that growth and survival of A. sachalinensis seedlings are reduced by canopy opening in that type of stand. A 0.75 ha study plot was examined, and all the seedlings (defined as trees with height 0.5-2 m) were identified and their shoot extensions measured for three years after single-tree selection harvesting (26% intensity in terms of basal area). The leader extensions of A. sachalinensis seedlings that experienced canopy opening were greatly improved. However, a negative effect on survival was also apparent; nearly 40% of seedlings died at the sites that experienced canopy opening. These results were supported by generalized linear models that examined variations of local harvesting intensity for individual seedlings. Despite the ability of A. sachalinensis to respond rapidly to exposure, some physiological stresses may have appeared, and presumably were amplified by co-occurring dwarf bamboos. With regard to the low seedling density (156 stems ha(-1)), common in this type of stands, local harvesting intensity in the selection system should be reduced to maintain survival of advanced regeneration, thus sustaining stand structure and composition.
  • Ishihara M., Sakai T., Saito S., Sakio H., Sakimoto M., Shibano H., Sugita H., Suzuki M., Takagi M., Takashima A., Takyu M., Ishida K., Tashiro N., Tanaka N., Tokuchi N., Namikawa K., Niiyama K., Nishimura N., Noguchi M., Nomiya H., Hiura T., Fujiwara A., Ida H., Hoshino D., Homma K., Makita A., Masaki T., Yoshioka T., Yoshida T., Itoh A., Enoki T., Ohkubo T., Kaneko T., Kaneko N., Kuramoto S.
    JAPANESE JOURNAL OF ECOLOGY 日本生態学会暫定事務局 60 (1) 111 - 123 0021-5007 2010 [Not refereed][Not invited]
     
    モニタリングサイト1000は環境省生物多様性センターの事業であり、そのうち森林・草原調査では、樹木、地表徘徊性甲虫、鳥類を指標生物群として定め、2004年よりモニタリング調査を行っている。本稿では、コアサイト・準コアサイトで取られた樹木に関するデータ(毎木調査データ)が研究・教育・保全政策などに広く活用されるよう、その概要を紹介し、データの活用方法について提案する。
  • 柴田 英昭, 戸田 浩人, 福島 慶太郎, 谷尾 陽一, 高橋 輝昌, 吉田 俊也
    日本森林学会誌 = Journal of the Japanese Forest Society 日本森林学会 91 (6) 408 - 420 1349-8509 2009/12/01 [Not refereed][Not invited]
     
    日本の森林生態系における物質循環と森林施業の関わりについて, 既往研究をレビューした。これまで, 森林伐採が物質循環や水質形成に及ぼす影響については, 伐採後に樹木の養分吸収が低下することによって, 河川へ硝酸態窒素が溶脱することが示されてきた。一方, 北海道北部における伐採後の林床植生による窒素養分吸収や, 関東北部での火山灰土壌における硝酸吸着, 流域水文過程に伴う河川水質変化など, 日本における特色あるプロセスについて報告されている。また, 急傾斜地における森林施業の結果として斜面崩壊が生じることで, 流域生態系の水文・水質形成過程が影響されることも示唆された。さらに, 河畔緩衝域での窒素除去, 河川流路内での栄養塩スパイラル, 里山における森林管理と物質循環変化など, 生態系境界域での研究が重要であることが指摘されている。今後は, 地域ごとの特性を考慮に入るとともに, 施業影響下での物質循環モデルのパラメタリゼーションなどをさらに推し進めることが重要である。
  • Hisashi Miya, Toshiya Yoshida, Mahoko Noguchi, Futoshi Nakamura
    JOURNAL OF FOREST RESEARCH 14 (5) 302 - 310 1341-6979 2009/10 [Refereed][Not invited]
     
    We analyzed temporal patterns in diameter growth of saplings following selection harvesting in an uneven-aged mixed stand dominated by Abies sachalinensis, Acer mono, Quercus crispula, and Betula ermanii in Hokkaido, northern Japan. We examined interspecific differences in growth responses to local growing conditions including harvesting intensity, crowding, stem size, and past duration of the small growth period. Consistent with expectations based on shade tolerance of the species, the age at which the individual reached a diameter at breast height (DBH) of 12.5 cm was highest for A. sachalinensis and lowest for B. ermanii. The interspecific growth differences between saplings that had or had not experienced local harvesting increased gradually for A. sachalinensis and B. ermanii, but peaked at around 4-6 years after harvesting for Q. crispula. Generalized linear mixed model analysis clearly suggested that individual growth conditions required to enhance diameter growth of saplings differed considerably among species. For Q. crispula and B. ermanii, local harvesting intensity was most strongly and positively associated with diameter growth rate, whereas for A. sachalinensis and A. mono, stem size had the strongest negative effect. Abies sachalinensis saplings responded more to surrounding harvesting when they were relatively small, whereas A. mono showed a weak opposite response. The duration of the small growth period before harvesting had negative effect for A. sachalinensis, but not for the other species. Our study indicated that the influence of selection harvesting on growth of shade-tolerant species depends upon pre- and post-harvest growing conditions.
  • Mahoko Noguchi, Toshiya Yoshida
    JOURNAL OF FOREST RESEARCH 14 (5) 311 - 320 1341-6979 2009/10 [Refereed][Not invited]
     
    We investigated the individual-scale responses of five dominant species (Abies sachalinensis, Acer mono, Tilia japonica, Quercus crispula, and Betula ermanii) to single-tree selection harvesting in a conifer-broadleaved mixed forest in Hokkaido, northern Japan. Using data from stems with a diameter at breast height of a parts per thousand yen12.5 cm, collected during 20 years of monitoring a 6.7-ha stand, we analyzed the effects of harvesting in the neighborhood on tree recruitment and the growth (diameter class transition) and mortality of the residual trees. The effects of harvesting varied considerably among tree sizes and species. Harvesting improved the recruitment of A. mono and B. ermanii, and moderated the negative effect of the initial basal area of the surrounding canopy trees on the recruitment of Q. crispula. Conversely, harvesting limited the recruitment of A. sachalinensis by offsetting the positive effect of the initial basal area of the surrounding canopy trees. The growth of A. sachalinensis and Q. crispula decreased with the initial basal area of the surrounding canopy trees. Harvesting in the neighborhood resulted in an improvement in the growth of the trees of these species only in the smaller size classes. With increasing local harvesting intensity, the mortality of smaller A. sachalinensis trees decreased, whereas the mortality of larger trees increased. These results suggest that differences in the local harvesting intensity, spatial patterns of harvesting, and initial stand structures influence the stand-scale dynamics in response to partial harvesting in the mixed forests of this region.
  • M. Katsuyama, H. Shibata, T. Yoshioka, T. Yoshida, A. Ogawa, N. Ohte
    SUSTAINABILITY SCIENCE 4 (2) 179 - 188 1862-4065 2009/10 [Not refereed][Not invited]
     
    We simulated hydrological and biogeochemical responses to logging in a forested watershed to determine the vulnerability and/or resiliency of the forest ecosystems in the Lake Shumarinai Basin in northern Hokkaido, Japan. We used a biogeochemical model (PnET-CN) and a rainfall-runoff model (HYCYMODEL) to predict ecosystem responses. The PnET-CN model simulated well the observed NO3 (-) concentrations in streamwater, particularly at high concentrations during snowmelt; however, the model could not simulate small increases in NO3 (-) during the summer. By considering hydrological processes within the watershed and combining the model with the HYCYMODEL (PnET + HYCYMODEL), the seasonality of streamwater NO3 (-) concentrations was better simulated. Using these models, the long-term effects of logging were simulated for coniferous, deciduous, and mixed forests. NO3 (-) concentrations in streamwater increased in response to the logging disturbance in both coniferous and deciduous forests. In the coniferous forest, NO3 (-) concentrations reached a maximum 10 years after logging, and high concentrations persisted for 30 years. In contrast, NO3 (-) concentrations in the deciduous forest reached a maximum within 3-4 years and recovered to pre-disturbance levels after 15 years. We also used the models to determine the effects of different sizes and types (coniferous, deciduous, and mixed forest) of logging areas on Lake Shumarinai. The model results indicated that large areas of cutting require more than 100 years for complete lake recovery. Whereas the annual discharge to the lake minimally increased, the annual NO3 (-) load greatly increased. Our simulation results elucidate the vulnerability and resiliency of forest ecosystems and provide valuable information for ecosystem management.
  • Toshiya Yoshida, Mahoko Noguchi
    ECOLOGICAL RESEARCH 24 (4) 909 - 919 0912-3814 2009/07 [Refereed][Not invited]
     
    This study examined historical census data to evaluate the vulnerability of major tall-tree species in northern Japan to strong winds. Intensive data, which measured more than 20,000 damaged trees (defined as trees that were killed or lost their major crown) in > 500 ha of a natural mixed forest, were collected immediately after a severe typhoon in 1954. More than half of the damaged trees had been uprooted, and the negative size-dependency was found for the proportion of uprooting throughout species. Simple correlation analyses with respect to the averaged species-specific characteristics suggested that tree species with a high crown-depth/height tended to uproot (against to stem breakage) in a size-class with diameter at breast height 30-50 cm. Although the census data had yielded no information about non-damaged trees, the estimation of pre-disturbed stand (based on 63 1-ha plot data together with aerial photographs and GIS) revealed that the observed damage reached ca. 25% in terms of basal area. The proportion of damaged trees seemed to be doubled among species (15-42% in basal area). A higher proportion of uprooting, which indicates a large supply of tip-up mounds, and mixture of less vulnerable species, might contribute to recovery process after a wind disturbance in this type of mixed forests.
  • Keiichi Aoyama, Toshiya Yoshida, Tomohiko Kamitani
    JOURNAL OF FOREST RESEARCH 14 (1) 58 - 62 1341-6979 2009/02 [Refereed][Not invited]
     
    We examined an alternative natural regeneration practice with a scarification treatment, in which removed soil is replaced on the scarified area, in northern Japan. The effect of the soil replacement on tree establishment was quite obvious; the basal area of trees, composed mostly of Betula ermanii, in the soil-replaced site was about 150-fold greater than that of the normally treated site. The greater growth rates together with higher density, both of which seemed to be enhanced by improved (i.e., deeper, tender, and nutrient-rich) soil properties, produced the marked difference to the normally treated site. The expected enhancement of species diversity owing to utilizing buried seeds in the replaced soil was not found. The current study revealed that the soil replacement could substantially improve forest restoration management with emphasis on biomass production for large nonwooded sites.
  • Hasegawa M, Aiura H, Takahashi Y, Yoshida T
    Journal of the Japanese Forest Society 一般社団法人日本森林学会 90 (6) 372 - 377 1349-8509 2008/12/01 [Not refereed][Not invited]
     
    To examine the potential of Alnus faurei for use in revegetation of disturbed steep hillsides, its growth and tree form were compared to those of traditionally used species: A. maximowiczii and A. hirsuta. The height and crown diameter of these three species, planted on disturbed slopes in a heavy snowfall region, were investigated for 9〜18 years. Also, the stem length and basal diameter of sprouts were compared between A. faurei and A. maximowiczii for 18 years. Results show that, more than the other two species, A. faurei favored crown enlargement over height growth; in spite of the tree ...
  • Harada A, Yoshida T, Resco de Dios Victor, Noguchi M, Kawahara T
    Journal of the Japanese Forest Society 一般社団法人日本森林学会 90 (6) 397 - 403 1349-8509 2008/12/01 [Not refereed][Not invited]
     
    Scarification is widely conducted in northern Hokkaido to remove understory dwarf bamboos in degraded forests, and to replace it with tree species. We investigated height growth and survival during 6〜8 years after the treatment for nine major tree species naturally established in a site, and examined their contributing factors (competition or facilitation). The height growth and survival rate were higher in Phellodendron amurense and Sorbus commixta, besides lower in Picea glehnii. The results of generalized linear model or generalized linear mixed model suggested that facilitation effects ...
  • Mahoko Noguchi, Toshiya Yoshida
    CANADIAN JOURNAL OF FOREST RESEARCH-REVUE CANADIENNE DE RECHERCHE FORESTIERE 37 (9) 1554 - 1562 0045-5067 2007/09 [Refereed][Not invited]
     
    The objective of this study was to assess the effects of fine-scale canopy disturbances induced by selection harvesting and its associated practices (artificial planting and machinery skidding) on the successful regeneration of tree species in a northern Japanese mixed forest. We set up 163 plots in a 6.7 ha permanent study stand where trees have been partially harvested at approximately 10-year intervals since 1974. The regeneration of trees (4324 stems center dot ha(-1)) occurred more frequently under closed canopies than under canopy gaps, except for a typical shade-intolerant species, Betula ermanii Cham. In particular, small canopy openings that tend to close quickly displayed higher understory tree regeneration densities likely due to the suppression of competition from dwarf bamboos. The surface soil disturbances that occurred during planting and harvesting even further enhanced understory regeneration. The results shown here should be generalized carefully because we have investigated only one stand. Nevertheless, our findings clearly indicated that the creation of small canopy gaps associated with site preparation that contains soil disturbances should be examined in management practices to maintain the community structure in this type of mixed forest.
  • Hasegawa M, Taira H, Yoshida T
    Journal of the Japanese Forest Society 一般社団法人日本森林学会 89 (1) 14 - 20 1349-8509 2007/02/01 [Not refereed][Not invited]
     
    In cold regions with snowfall in Japan, unsuccessful Cryptomeria japonica plantations are often intended to convert into more natural forest in recent years. To improve such a practice, we examined effects of weeding frequency (initial 10-years, vs. only initial 3-years) on density and growth of planted Fagus crenata, the most representative species in primeval forests, and naturally colonized broadleaved species. Although planted F. crenata was suppressed by colonized species, the mortality was lower in the infrequent site (TE) than in the frequently weeded site (WD). The mean diameter at ...
  • Toshiya Yoshida, Mahoko Noguchi, Yukio Akibayashi, Masato Noda, Masahiko Kadomatsu, Kaichiro Sasa
    CANADIAN JOURNAL OF FOREST RESEARCH-REVUE CANADIENNE DE RECHERCHE FORESTIERE 36 (6) 1363 - 1375 0045-5067 2006/06 [Refereed][Not invited]
     
    Single-tree selection has been employed widely in northern Japanese mixed forests, but management-induced changes in forests are not well understood. This study examined demographic parameters of major tree species during a 20-year study of a 68 ha stand in which single-tree selection has been conducted since 1971. Results showed that growth and survival of conifers (mostly Abies sachalinensis (Fr. Schm.) Masters) was the most strongly positively affected by the treatment. Nevertheless, recruitment of conifers was not sufficiently improved, suggesting their decreased dominance over the longer term. Instead, shade-intolerant broad-leaved species (mainly Betula ermanii Cham.) will gradually increase because of their higher recruitment rates after the treatment. Shade-tolerant broad-leaved species (mainly Acer mono Maxim. and Tilia japonica (Miq.) Simonkai) appeared to experience the most distinct negative effects, especially on survival. These trends differed markedly from those reported in previous papers concerning partial harvesting systems, which predicted an increase in dominance of shade-tolerant species. The results shown here should be generalized carefully because we have investigated only one stand without repetition of the control area. Nevertheless, trends described in this large-scale, long-term study could provide a basis for simulating stand dynamics. We discussed possible reasons for the observed patterns and provided implications for sustainable management in the region.
  • M Nagai, T Yoshida
    JOURNAL OF FOREST RESEARCH 11 (1) 1 - 10 1341-6979 2006/02 [Not refereed][Not invited]
     
    We investigated effects of silvicultural treatments (planting and subsequent treatments) on understory structure and plant species diversity in managed Picea glehnii plantations (21-26 years old) in northern Japan. We evaluated the importance of each treatment (machinery site preparation, planting, weeding, and thinning) in 19 plantations, with considerable variation among treatments overall. The understory had 98 vascular plant species; the most dominant species was a dwarf bamboo Sasa senanensis, followed by tree species Abies sachalinensis and Betula ermanii. Multiple regression analyses showed that thinning negatively influenced plant species diversity. Planting density showed a strong positive correlation with density of seedlings (height <20 cm), but few independent variables were correlated with density of saplings (height >= 20 cm and diameter at breast height <1 cm). The negative effect of thinning and the positive effect of planting density seem to be related to the existence or reinitiation of dense cover of Sasa senanensis. We present possible mechanisms of response to treatments to generalize the results. We then suggest ways to improve current treatments to meet the goals of wood production and biodiversity conservation in the region.
  • T Yoshida, M Hasegawa, H Taira, M Noguchi
    JOURNAL OF FOREST RESEARCH 10 (5) 351 - 358 1341-6979 2005/10 [Not refereed][Not invited]
     
    Tree retention is understood as a key practice in creating complexity, leading to heterogeneity in resources and habitats in managed stands. In this article, we clarify the long-term effects of tr e retention on stand structure and tree-species composition in a 60-year-old Larix kaempferi plantation in central Japan. In our study plot (1.5ba) there were 18 stems/ha of retained trees (determined by tree-ring analysis), mostly Quercus crispula. We conducted spatial analyses and tested the hypothesis that tree abundance, size structure, and species composition and diversity change with distance from the retained trees. Near the retained trees, L. kaempferi showed a reduction of 40%-60% in basal area, due presumably to the shading effect. In contrast, the nearby area showed greater species diversity in the canopy layer. The retained trees created patches of different species composition in the understory. The spatial gradient of shade and colonization opportunity provided by retained trees greatly affect the distribution of the colonized species, according to their shade tolerance and seed-dispersal ability, which resulted in the stand structure with a heterogeneous shrub-layer vegetation. Retention proved particularly important for the enhancement and long-term maintenance of structural and compositional complexity in L. kaempferi plantations.
  • VR de Dios, T Yoshida, Y Iga
    FOREST ECOLOGY AND MANAGEMENT 215 (1-3) 138 - 148 0378-1127 2005/08 [Refereed][Not invited]
     
    Dwarf bamboo creates a dense carpet that prevents forest regeneration in mixed forests of Japan. Soil-scarification has been used widely to regenerate such forests. However, no study has specifically addressed the effects of soil-scarification on regeneration dynamics following such perturbation. This study analyzed the demography and community structure of the most abundant species 6 years after soil-scarification in a mixed forest stand of Northern Japan. We used canonical correspondence analysis (CCA) to analyze environmental factors effects on species distribution. Using multiple regression analysis, we determined the net balance of competition and facilitation. Abies sachalinensis and Picea glehnii are the most abundant species; Betula sp. and Salix bakko are the largest ones. Increasing distance to the edge of the scarified area is generally concomitant with decreasing seedling density, but changes in extension growth show idiosyncratic responses. These results, together with those of CCA, suggest that light is the main factor directly affecting (with high levels of irradiance) and indirectly affecting (by changing volumetric soil water content) seedling demography and structure. Multiple regression analyses show that facilitation is the most important interaction affecting seedling growth, probably by reducing excess levels of irradiance. (c) 2005 Elsevier B.V. All rights reserved.
  • 秋林幸男, 高木健太郎, 野村睦, 北条元, 菅田定雄, 柴田英昭, 福沢加里部, 吉田俊也, 小池孝良, 笹賀一郎, 藤沼康実, 前林衛
    北方林業 57 (8) 176 - 179 0388-8045 2005/08/01 [Not refereed][Not invited]
  • 吉田慎一, 吉田俊也, 富岡輝男, 早柏慎太郎, 秦寛
    日本草地学会誌 51 16 - 17 0447-5933 2005/03/26 [Not refereed][Not invited]
  • M Noguchi, T Yoshida
    ECOLOGICAL RESEARCH 20 (1) 25 - 30 0912-3814 2005/01 [Not refereed][Not invited]
     
    We have investigated the factors influencing the distribution of co-occurring two dwarf bamboo species, Sasa kurilensis (Ruprecht) Makino et Shibata and S. senanensis (Franchet et Savatier) Rehder, within a conifer-broadleaved mixed stand managed with selection cutting in northern Japan. We first sought the possible determinant factors (physical environment and overstory conditions based on 30 years' tree census data) deciding the dominant species in the plots (1683.14 m(2) area). We then examined the effects of these factors on the culm density and height of the dominant species. Linear discriminant analysis indicated that physical environmental conditions are important in determining the distribution; S. kurilensis tended to dominate plots with steep slope, convex shape and deep snow in early spring. Multiple regression analyses showed that culm density and height decreased significantly on steep slopes for both species. Also, the sum of the basal area (BA) of surrounding conifers (7.5 m radius around the plot), as well as the change in BA over the previous 30 years, had a negative influence on the culm height of both species. A reduction in overstory trees, caused by natural or artificial canopy disturbances, would increase the dwarf bamboo biomass. The effects of physical environment and overstory conditions, working through the dominance of the two dwarf bamboo species, should be taken into account in understanding the dynamics of natural forests in this region.
  • T Yoshida, Y Iga, M Ozawa, M Noguchi, H Shibata
    CANADIAN JOURNAL OF FOREST RESEARCH-REVUE CANADIENNE DE RECHERCHE FORESTIERE 35 (1) 175 - 188 0045-5067 2005/01 [Not refereed][Not invited]
     
    Scarification is widely conducted in northern Japan to remove understory dwarf bamboo species in degraded forests for replacement with tree species. To explore ways to enhance species diversity and restoration of mixed forest at the treated site, we clarified the mechanisms that lead to compositional heterogeneity of plant species. We evaluated the relative importance of environmental factors (scarification properties, soil properties, light conditions, litter cover, and presence of canopy trees) for the demography of tall tree species (emergence, mortality, and growth) and whole vegetation structure (species diversity and composition) over the two growing seasons immediately following scarification. Of tall tree species, Betula spp. were dominant (60% in total density), followed by Abies sachalinensis (Fr. Schm.) Masters, Acer mono Maxim., and Phellodendron amurense Rupr. Light intensity was an important factor, having mostly negative effects on the demography of these species. Soil factors (e.g., nitrogen content, moisture) affected the demography mainly of shade-intolerant or hygrophilous species. In general, extreme environmental conditions led to the dominance of grasses, forbs, and lianas rather than tall trees. Maintenance of canopy cover, which limits light and supplies seeds as well as litter, proved to be most important in promoting plant species diversification on the scarification site.
  • 吉田 俊也, 野口 麻穂子
    北方林業 北方林業会 56 (7) 162 - 165 0388-8045 2004/07 [Not refereed][Not invited]
  • 吉田俊也, 野口麻穂子
    北方林業 56 (7) 162 - 165 0388-8045 2004/07/01 [Not refereed][Not invited]
  • M Noguchi, T Yoshida
    FOREST ECOLOGY AND MANAGEMENT 190 (2-3) 335 - 344 0378-1127 2004/03 [Not refereed][Not invited]
     
    We assessed the relationship of the regeneration (seedling and sapling) densities of seven representative tall-tree species to the past partial cutting and current stand structure. We also determined if differences in tree regeneration were associated to establishment substrates (coarse woody debris (CWD) and root throws) and understory inhibitor vegetation (the dwarf bamboo species: Sasa senanensis). The study was conducted in 17 conifer-hardwood mixed stands in a heavy snowfall region in Hokkaido, northern Japan. The results suggest that stand structure, rather than logging intensity, is the primary factor influencing regeneration densities. Total conifer basal area was positively correlated with the regeneration density of individual tree species, including two conifers and three hardwoods. These patterns differ from those observed in old-growth stands in the region. A negative correlation between total conifer basal area and dwarf bamboo coverage suggests that the presence of dense conifer canopies causes an increase in regeneration density of tall-tree species by preventing domination of dwarf bamboo. Picea glehnii, a species that depends for its establishment strongly on CWD, has lower seedling and sapling density in stands with higher logging intensity. This seems to be a result of the decrease in the volume of CWD with increasing logging intensity in these stands. We suggest that both reducing logging intensity and retaining overstory conifers should be considered to develop a sustainable silvicultural system in this region. Providing sufficient CWD and root throws may also be important to ensure natural regeneration of tree species that require these as an establishment substrate. (C) 2003 Elsevier B.V. All rights reserved.
  • 秦 寛, 富岡 輝男, 尾島 徳介, 吉田 俊也, 植村 滋, 竹田 哲二
    日本草地学会誌 日本草地学会 49 (0) 208 - 209 0447-5933 2003/03/24 [Not refereed][Not invited]
  • 秦寛, 富岡輝男, 尾島徳介, 吉田俊也, 植村滋, 竹田哲二
    Grassl Sci 49 208 - 209 0447-5933 2003/03/24 [Not refereed][Not invited]
  • H Kurokawa, T Yoshida, T Nakamura, JH Lai, T Nakashizuka
    JOURNAL OF TROPICAL ECOLOGY 19 1 - 7 0266-4674 2003/01 [Not refereed][Not invited]
     
    Using C-14 dating, the life span and growth rate of Borneo ironwood (Eusideroxylon zwageri, Lauraceae), which is a canopy tree species with extremely durable and decay-resistant wood distributed in tropical rain forests of South-East Asia, were studied. Timber segments collected from 15 logged stumps in Kubah National Park, Sarawak, Malaysia, were analysed by accelerator mass spectrometry and the obtained data were calibrated to determine the age of individuals. The C-14 dating turned out to be an effective method for estimating ages of long-lived trees, such as E. zwageri, in the aseasonal tropics because the estimated error was small compared with estimated age. We found that E. zwageri can live more than 1000 y and that the growth rate of this species was very slow, with a mean radial growth rate of 0.058 cm y(-1). The life span was much greater and the growth rate was much slower than those observed or estimated for trees of Dipterocarpaccae, the dominant family in this tropical forest. The long life span of this species may be caused by wood durability with a high specific gravity and abundant defensive compounds; Given equal carbon allocation, the high density and carbon-based defensive compounds may result in a reduced growth rate.
  • 鷹西俊和, 吉田俊也, 竹田哲二, 上浦達哉, 阿部一広, 高橋広行, 中嶋潤子, 原臣史, 小沢恵
    北方林業 北方林業会 54 (5) 97 - 99 0388-8045 2002/05/01 [Not refereed][Not invited]
  • Stem growth and interspecific competition in a broadleaved secondary forest, central Japan.
    Eurasian Journal of Forest Research 4 51 - 84 2002 [Not refereed][Not invited]
  • T Yoshida, T Kamitani
    FOREST ECOLOGY AND MANAGEMENT 137 (1-3) 221 - 230 0378-1127 2000/10 [Not refereed][Not invited]
     
    We investigated causes and consequences of interspecific competition among canopy-tree species with different shade-tolerance. The shading effects caused by neighbors were determined fur three tree species, shade-tolerant Fagus crenata, and intermediate tolerant Quercus crispula and Magnolia obovata, in six even-aged stands containing different proportions of each species. The competitive attributes (sensitivity to suppression and intensity of shading) varied considerably among species. Shade-tolerant F. crenata caused most intensive shading effects probably because of its deeper crown depth. Less-tolerant Q. crispula decreased its stem growth and crown depth markedly in association with the presence of shade-tolerant F. crenata. In contrast, F. crenata and M. obovata were less influenced by their neighbors; it may be due to its own higher shade-tolerance in the case of F. crenata and larger initial growth rates in ill. obovata. We suppose that differences in initial species composition may lead a species to have different dominance in stand development. When shade-tolerant species are absent in mixture, less shade-tolerant species could maintain their dominance for a long period. In contrast, mixture with tolerant species would reduce the dominance of less-tolerant species, unless they had growth advantage in early stage in development. (C) 2000 Elsevier Science B.V. All rights reserved.
  • Yanagisawa Yukiko, Yoshida Toshiya, Kamitani Tomohiko
    Journal of forest research 一般社団法人日本森林学会 4 (1) 53 - 56 1341-6979 1999/02/16 [Not refereed][Not invited]
     
    A new method for predicting understory light levels around an artificial canopy gap prior to the selective cutting is presented. In two even-aged coppice stands, hemispherical photographs were taken at a height of 1.3 m, and crowns of each canopy stem on the photographs were identified by field observations. To predict light levels after cutting, we used computerized images of the hemispherical photographs, in which we digitally erased all crowns to be cut (named 'erasing method'). Light levels were calculated by an analyzing program; HEMIPHOT. Light levels predicted by the 'erasing method'...
  • T Yoshida, T Kamitani
    FOREST ECOLOGY AND MANAGEMENT 113 (1) 57 - 65 0378-1127 1999/01 [Refereed][Not invited]
     
    A generally accepted trend in secondary succession - the decline in dominance of shade-intolerant species was examined. We dealt with a shade-intolerant species, Phellodendron amurense Rupr. in a 38 ha mixed-species coppice forest. There were 45 stems of P. amurense with dbh (diameter at breast height) greater than or equal to 10 cm in the forest. P. amurense had smaller means of stem sizes (dbh, height, and crown ratio) and basal area increments than those of their neighbors. Analysis on choosing cores indicated that most of P. amurense had already been under a suppressed condition at 20 years after their establishment, and obviously showed decline in growth during the following stages. Although they could grow faster without any suppression, their sensitivity to shading effects was greater than other more tolerant species. It seemed that suppression by species with deep crowns was particularly prominent. Such extreme responses to suppression seemed to cause decrease in growth rate after the onset of suppression in the actual forest. We conclude that two factors: the relative growth rates in the initial stage, and the species composition in the following stage are considered to be definitive in the declining process of P. amurense. (C) 1999 Elsevier Science B.V. All rights reserved.
  • T Yoshida, Y Yanagisawa, T Kamitani
    FOREST ECOLOGY AND MANAGEMENT 109 (1-3) 85 - 89 0378-1127 1998/09 [Refereed][Not invited]
     
    An empirical model for predicting light levels under a canopy gap in an even-aged oak stand is presented. The effects of gap size, distance from the gap, and directional position (noah-south) within the gap on gap light index (GLI) [sensu Canham, C.D. 1988. An index for understory light levels in and around canopy gaps. Ecology 69, 1634-1638] are quantified by multiple regression analysis. Data were obtained by the 'erasing method' (Yanagisawa et al., in preparation') which predicts the GLI from computerized images of hemispherical photographs. Forty-five 'virtual canopy gaps' were assumed, and at 945 points, light levels were calculated using HEMIPHOT [ter Steege, H. 1993. HEMIPHOT, A Programme to Analyze Vegetation Indices, Light and Light Quality from Hemispherical Photographs. The Tropenbos Foundation, Wageningen, The Netherlands]. The model presented in this study has the advantage that the indices needed for the prediction can be measured easily in field survey. The applicability of the model is discussed. (C) 1998 Elsevier Science B.V.
  • Yoshida Toshiya, Kamitani Tomohiko
    Journal of forest research 一般社団法人日本森林学会 3 (3) 181 - 184 1341-6979 1998/08/16 [Not refereed][Not invited]
     
    We compare three or four years effects of crown release on stem growth rates among four deciduous broad-leaved tree species, Fagus crenata, Quercus crispula, Magnolia obovata and Acer mono, in an e\"en-aged coppice forest, central Japan. The crown release significantly improved relative growth rates for basal-area (RGR<BA>) of the four species. However the effects of neighboring gap area (GAPA) on the RGR<BA> differed among the species. The effects were slgnificant for Q. crispula and M. obovata, indicating that growth rates of these two species increase with intensity of the crown release....
  • T Yoshida, T Kamitani
    FOREST ECOLOGY AND MANAGEMENT 95 (1) 35 - 43 0378-1127 1997/07 [Refereed][Not invited]
     
    We investigated stand dynamics of a mixed coppice Forest of shade-tolerant and intermediate species, Fagus crenata Bl. and Quercus crispula Bl., in five stands with canopy-stem densities from 420 to 1320 ha(-1) (estimated stand age: 37-62 years). The mean basal area (BA), exposed-crown area (ECA) and crown depth (CD) per stem were significantly larger in F. crenata in the three lower density plots. Also Q. crispula had considerably less overtopped stems in the two lower density plots. The mean annual BA increments of the two species were similar in the earlier 20 years; however, in the most recent 5 years, F. crenata had a higher relative growth rate for basal area (RGR(BA)) than Q. crispula. The most critical variable of the RGR(BA) was the ECA for F. crenata and the relative height (RH) for Q. crispula. We predict that dominance of F. crenata will gradually increase over that of Q. crispula as stands mature. This seems to be caused by lower shade-tolerance despite the similar initial growth rates of Q. crispula compared with F. crenata. (C) 1997 Elsevier Science B.V.
  • KAMITANI Tomohiko, YOSHIDA Toshiya
    Journal of the Japanese Forestry Society 一般社団法人日本森林学会 73 (2) 154 - 157 0021-485X 1991/03/01 [Not refereed][Not invited]

Books etc

  • 森への働きかけ-森林美学の新体系構築に向けて
    海青社 2010
  • Management for forests
    Kaiseisha 2010
  • 北の森づくりQ&A
    北方林業会 2009
  • 北海道北部の地域社会-分析と提言
    筑波書房 2008
  • 吉田 俊也 
    [北海道大学北方生物圏フィールド科学センター] 2008
  • 森林の科学-森林生態系科学入門-
    朝倉書店 2005
  • Restoration of Boreal and Temperate Forests.
    CRC Press 2005

Conference Activities & Talks

MISC

Awards & Honors

  • 2008 日本森林学会奨励賞

Research Grants & Projects

  • 天然林施業を組み入れた地域の森林管理オプションの提示 研究課題
    文部科学省:科学研究費補助金(基盤研究(C))
    Date (from‐to) : 2014/04 -2017/03 
    Author : 吉田 俊也
     
    木材の利用と生態系の保全とのバランスを考慮した天然林の管理について、北海道北部をモデル地域として考察した。択伐施業試験地における長期データから得られた主要樹種の個体群動態パラメータ、および樹種による伐採に対する反応の違い、天然更新補助作業等の効果を反映させた森林動態シミュレーションを実施した。森林の蓄積や、生物多様性の維持に寄与する構造を長期にわたって維持する森林施業の要件を、経済的な持続可能性も考慮して提示した。
  • 北方林における攪乱後の主要樹種の成長と死亡:長期ストレスとしての個体間競争の影響
    文部科学省:科学研究費補助金(基盤研究(C))
    Date (from‐to) : 2014/04 -2017/03 
    Author : 大野 泰之
  • 文部科学省:科学研究費補助金(基盤研究(B))
    Date (from‐to) : 2010 -2012 
    Author : 久保田 康裕, 吉田 俊也, 榎木 勉
     
    北方域の気候変動や森林施業による人為インパクトは、将来的な北方林の資源動態に大きな影響を及ぼしつつある。本研究では、北方域の針葉樹林帯における山火事撹乱の強度・頻度の変化が、木材資源動態に及ぼす影響を、実データに基づいた空間点過程モデルと個体ベースの森林動態シミュレータで分析しようとしている。本研究は、従来の地域限定型の資源保全研究とは一線を画し、環北方域の森林動態に共通した生態プロセスを解明する。今年度は研究初年であるため、フィンランドの共同研究者を相手国のマッチングファンドで招聘し、研究計画全体について会議を行い、調査計画と論文執筆計画を策定した。この会議では、山火事撹乱が変化した場合、北方林が低密度林やヒースに劣化するメカニズムを明らかにし、環境変動に適応し汎用性のある持続的森林施業のオプションを提示することを確認した。北方林の山火事撹乱は、その頻度と燃焼強度に負の相関がある。燃焼強度の高い山火事が稀に発生する場合、高密度の針葉樹林が更新し、次の山火事までに複数世代の樹木が共存する異齢林が発達する。山火事の頻度が高く燃焼強度も弱くなるに伴い、針葉樹の更新密度は低下し、同齢の低密度林からヒースへと衰退する。フィンランド北部の森林構造の空間変異や更新様式の差異は、このような山火事撹乱の頻度と強度の変異に対応していると考えられる。以上のプロセスを分析するため、本年度は、山火事...
  • 文部科学省:科学研究費補助金(基盤研究(C))
    Date (from‐to) : 2010 -2012 
    Author : 長池 卓男, 吉田 俊也
     
    社会的背景を考慮した新たな人工林施業を考えるために、複数の樹種を植栽した混交植栽人工林において、(1)炭素固定機能を地上部の蓄積量・成長量および成長経過から明らかにし、(2)立木の個体間距離や立木密度から、混交植栽人工林における林分構造・林内光環境・土壌養分が相互作用的に及ぼす炭素固定機能(生産性)への影響を定量化し、単一植栽人工林と比較する。このことによって、混交植栽人工林において生産性を損なわないための間伐指針を明らかにする。山梨県有林内のすべての混交植栽人工林のリストアップを行った。樹下植栽による複層林や混植された広葉樹造林地を含めて、6142小班が混交植栽人工林であった。森林簿から、単一植栽人工林と混交植栽人工林での材積の比較を行った。山梨県鳴沢村内の列状伐採された41年生のカラマツ-シラベ人工林において、100×80mの調査区を設定した。胸高直径3cm以上の立木を対象として毎木調査を行った。調査区あたりの立木密度はカラマツ260本、シラベ285本で、全体の47%、51%をそれぞれ占めていた。しかしながら胸高面積合計でみるとカラマツ33%、シラベ65%と、シラベの割合が増大していた。平均胸高直径でみても、カラマツ19.7cmに対しシラベ26.4cmと、シラベの方が優勢な成長をしていた。樹高・樹冠体積においてもシラベの方が優勢で、常緑樹であるシラベが落葉樹であるカラマツ...
  • 文部科学省:科学研究費補助金(基盤研究(C))
    Date (from‐to) : 2011 -2011 
    Author : 吉田 俊也
  • 文部科学省:科学研究費補助金(基盤研究(B))
    Date (from‐to) : 2009 -2011 
    Author : 笹 賀一郎, 佐藤 冬樹, 柴田 英昭, 吉田 俊也, 野村 睦, 高木 健太郎
     
    本研究は、北海道大学北方生物圏フィールド科学センターの雨竜研究林と天塩研究林の操作実験流域を主な対象として、原生林状態から森林伐採・表土除去・樹木の植栽などの炭素や窒素などの物質循環への影響を地下部・根茎の状況もふくめて明らかにしようとするものである。平成21年度の主な成果は、以下のようである。1.天塩研究林の実験流域において、原生林伐採後に植栽したカラマツのバイオマスについて、根茎もふくめた測定をおこなった。また、前年度におこなった15m×15m林分の地下部調査については、根茎等の分析用サンプルの乾燥をすすめるとともに、樹種ごとの根茎量等についてのデータをとりまとめた。2.雨竜研究林・天塩研究林の実験流域においては、炭素・窒素の動態変化に加えて、水分や炭素・窒素以外の物質、および土砂・浮遊砂等に関する観測を継続した。とくに、下流域に対する溶存鉄の供給については、北方針広混交林は供給が少ないという特徴をもちながらも、森林は持続的な溶存鉄生成と供給の役割を果たしていることを明らかにした。さらに、冬季間の観測から、積雪期においても窒素の無機化や硝化は進行し、降雪前にはアンモニアの生成が進行し、融雪期には硝酸の生成か進行すること、積雪量の減少によって融雪期のアンモニア正味生成量の増加と硝酸の正味生成量が減少することなどを明らかにした。3.原生林伐採とカラマツ植栽によるCO2フラック...
  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(基盤研究(C))
    Date (from‐to) : 2006 -2007 
    Author : YASUHIRO KUBOTA, 榎木 勉, 吉田 俊也
     
    This paper formulates the inhomogeneous Neyman-Scott process so as to include both the inhomogeneous Poisson process and the Neyman-Scott process as specific cases, and derives the analytical expression of its Palm likelihood. This enables us to compare models with only niche, only dispersal and both on the common theoretical base directly, thus leads us to the quantification of their relative importance. The model was applied to the black spruce populations which has limited seed dispersal due to gravity and the amount of soil organic matters have strong influences in the regeneration afte...
  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(基盤研究(C))
    Date (from‐to) : 2005 -2007 
    Author : Toshiya YOSHIDA, 久保田 康裕, 長池 卓男, 野口 麻穂子
     
    We evaluated the effects of selection harvesting on forests in Hokkaido, northern Japan, based on the long-term ecological monitorings in combination with recent field surveys. In stands located in northern Hokkaido, the effects were generally negative (Yoshida et al. 2006), especially for recruitment of juvenile trees (Noguchi and Yoshida 2007). The differences in the response among species were examined in detail, with emphasis on particular sensitive species.Nevertheless, these trends were appeared to be region-specific, as the contrasting results were obtained in stands in eastern Hokka...
  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(基盤研究(A))
    Date (from‐to) : 2005 -2007 
    Author : Fuyuki SATOH, 笹 賀一郎, 小池 孝良, 柴田 英昭, 吉田 俊也, 高木 健太郎
     
    The carbon-, water- and mineral cycling were investigated in the Larix forest watersheds, associated with growth, succession and carbon storage, of southern limit area of permafrost region of Far East Asia. The research sites were set in the Larix (Larix gmelinii) forests of a) Maoershan Experimental Forestry Center, north Northeast Forestry University, Harbin, China (seasonally frozen area), b) the Greater Khingan Range, China, c) Mo-he, northernmost of China and d) Blagobeshensk, Amur Region, Russia (discontinuous permafrost region). The site c) and d) were affected by the forest fires re...
  • 文部科学省:科学研究費補助金(若手研究(B))
    Date (from‐to) : 2002 -2004 
    Author : 吉田 俊也
     
    A.北海道大学雨龍研究林内に設定した人口裸地プロット(造成後4年目,重機による「掻き起し」施業地)における調査を継続して行った。2年目までの光・土壌・生物環境の変化と,出現する植生との関係はすでに明らかになっている(Yoshida et al.2005)。今年度は,植生の発達に伴って発言すると考えられる植物種内・種間の競争関係を解析に加えるため,1.96ha(140×140m)の調査プロットに設置された60ヶ所の調査区において,植生センサス(2回/年:高木性樹種の雅樹は固体識別),土壌資料の採取および窒素濃度の測定を行なった。B.「掻き起し」施業後の8年が経過したプロットにおいて,施業後に発生した高木性樹種の雅樹の動態を明らかにした。この段階では,雅樹間の競争関係は少なく,高い周辺密度はむしろ成長を促進していることがわかった。また,他の下層植生・周辺の上層木の存在も,生長にポジティブな効果を与えていた。一方,同じ施行年で,掻き起し施業1年後に,取り除いた表土を再び施業地に戻したプロットでも調査を行った。表土を戻した箇所では,通常の施工地に比べて数十倍以上の生長が見られた。また雅樹の発生も多いことから,このような施工方法は,森林の回復速度を高め,また森林の階層構造のすばやい発達にも寄与することが示唆された。C.この地域の森林の林床優占種であるササ類と,他の林床植生との関係を調査...
  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(基盤研究(B))
    Date (from‐to) : 2001 -2003 
    Author : Hideaki SHIBATA, 植村 滋, 吉岡 崇仁, 大手 信人, 高木 健太郎, 吉田 俊也
     
    To clarify the effect of vegetation and land-use on biogeochemical processes in combined watershed including the forest, wet land and agricultural land, analysis of land-use characteristics, vegetation pattern, solute chemistry and dynamics in stream and lake were investigated in the Shimarinai Rake watershed located in northern Hokkaido Japan. Terrestrial vegetation pattern in the watershed was affected the soil moisture condition which closely related to the topographic features. The wetland and swamp forest distributed in the lower slope and riparian area played a significant role on the...
  • 生態系の保全を考慮した森林の施業方法に関する研究
    Date (from‐to) : 1999
  • Forestry management with considering ecosystem sustainability in Japan
    Date (from‐to) : 1999


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