Published Papers - YAMAZAKI Haruka
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Changes of ground beetles and Araneids fauna in the forest management sites where were constructed assisted natural regeneration using heavy machinery
2025.09 [Refereed]
International Conference Proceedings Multiple authorship
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The regeneration characteristics of Juglans mandshurica var. siedoldiana - seed dispersal, germination, and the growth of annual seedlings -.
2025.09 [Refereed]
International Conference Proceedings Multiple authorship
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Predicting the Size Distribution of Lacquer Tree Plantations Based on Y-N Theory and Estimation of the Maximum Yield of Urushi Sap at Stand Level
106 ( 7 ) 190 - 197 2024.11 [Refereed]
Academic Journal Multiple authorship
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Scarification with surface soil replacement can promote understory reinitiation as well as the growth of a secondary birch stand
Toshiya Yoshida, Haruka Yamazaki, Toshizumi Miyam
Journal of Forest Research ( Taylor and Francis Ltd. ) 2022.07 [Refereed]
Bulletin of University, Institute, etc. Multiple authorship
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Takashi Kunisaki,Haruka Yamazaki
103 ( 4 ) 285 - 290 2021.08 [Refereed]
Academic Journal Multiple authorship
The stand growth process of an overcrowded old-growth
plantation of Japanese Cedar (Cryptomeria japonica D. Don) was investigated for 41 years, beginning when the stand was 134 years old, in the slope and flat site. In the slope site, since very weak cutting of about 10% in number ratio was carried out several times, overcrowding
condition could not be eliminated and mortality continued. However, as the trees were continuously cut down, the degree of crowding gradually improved and DBH growth increased, average height: DBH ratio decreased to less than 70, and net increment in stand volume reached more than 10 m3/ha/year. In the flat site, the low thinning of 22% in number ratio was carried out, when the stand was 146 years old, and overcrowding condition was eliminated and mortality stopped. As DBH growth increased, average height: DBH ratio decreased to less
than 70 and net increment in stand volume increased to around 20 m3/ha/year. It was confirmed that since the tree height growth continues at first site class, the net stand volume increment would be around 20 m3/ha/year for about 20 years, if lower thinning is conducted to exceed 15% of the relative spacing index. -
Early establishment of spruce (Picea glehnii [Fr. Schm.] Masters) seedlings on disturbed soil with the aim of assisted natural regeneration
Nanami SUZUKI, Toshiya YOSHIDA, Toshizumi MIYAMOTO, Karibu FUKUZAWA, Shingo TANIGUCHI, Haruka YAMAZAKI
Scandinavian Journal of Forest Research ( Nordic Forest Research ) 2021.03 [Refereed]
Academic Journal Multiple authorship
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YAMAZAKI Haruka, MAMIYA Wataru, YOSHIDA Toshiya
Journal of the Japanese Forest Society ( Japanese Forest Society ) 102 ( 3 ) 157 - 165 2020.06 [Refereed]
Academic Journal Multiple authorship
Soil scarification by heavy machinery is often applied to enhance regeneration of tall trees in dwarf bamboo grassland. The "replacement treatment", which spreads the scarified debris to the treated area, is an alternative practice of standard soil scarification to contribute to growth improvement and generation from buried seeds. In this treatment, a deposition period has been set for the purpose of restraining the recovery of dwarf bamboos from rhizomes, but its appropriate period has not been examined. In this study, we compared regeneration of competitive vegetation and tree species among three different deposition periods (0, 2, and 12 months) in consideration of the pre-existence of tall forbs. The recovery of dwarf bamboos was restrained when the deposition period was long. On the other hand, the prevalence of a tall-forb, Fallopia sachalinesis in particular, which germinated from rhizomes increased when it had existed as previous vegetation, and only the 12 months deposition could prevent its dominance. The effect of the prolongation of the deposition period for the regeneration of tall-tree species was positive in Betula and Salix species and negative in Phellodendron amurense. However, the differences among the treatments were unclear where tall forbs had not existed. We conclude that a deposition period of 12 months is required for a site with pre-existing tall forbs, but the replacement without a deposition period can be applied for a site without tall-forbs,
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Haruka YAMAZAKI, Toshiya YOSHIDA
Journal of Forest Research ( Japanese Forest Society ) 25 ( 1 ) 41 - 50 2020.01 [Refereed]
Academic Journal Multiple authorship
Soil scarification removed surface layers including nutrients and buried seeds. The purpose of this study was to evaluate the success of alternative practices that intentionally leave the surface soil (screening and replacing) along with the standard scarification. We focused on soil properties, the density of buried seeds, the invasion of competitive vegetation, and the regeneration of tree species. There were significant differences in soil properties among the treatments. Soils that were treated with the replacing treatment had the highest water contents from the surface layer to the deep layer in the lower slope in particular. On the other hand, there were higher densities of tall forb germinated from rhizomes, which are likely to shade tree species, with the replacing in the lower slope locations. The residual buried seed densities in the soil were estimated to be significantly higher in the screening than the replacing. Phellodendron amurense, producing seed bank and having dry tolerance, exhibited the greatest seedling density with the screening. However, there was no significant difference between screening and replacing in Betula species which has higher water demands. In conclusion, it is important that screening and replacing should be used properly according to the site condition and target tree species. The replacement had the advantage of retaining higher water content, but it is suggested that the screening is a better option when intended for regeneration from buried seeds and when many tall forb species grow alongside dwarf bamboo prior to treatment.
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Haruka YAMAZAKI, Toshiya YOSHIDA
Journal of Forest Research ( Japanese Forest Society ) 23 ( 3 ) 166 - 172 2018.03 [Refereed]
Academic Journal Multiple authorship
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.
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Toshiya Yoshida, Sayoko NAITO, Misato NAGUMO, Natsumi HYODO, Taiki INOUE, Hiromitsu UMEGANE, Haruka YAMAZAKI, Hisashi MIYA, Futoshi NAKAMURA
Sustainability ( Mary Ann Liebert Inc. ) 9 ( 11 ) 2093 2017.11 [Refereed]
Academic Journal Multiple authorship
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.
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Tsuyoshi SATO, Haruka YAMAZAKI, Toshiya YOSHIDA
Journal of Forest Research ( Japanese Forest Society ) 22 ( 6 ) 336 - 342 2017.09 [Refereed]
Academic Journal Multiple authorship
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.
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Ippei ASADA, Haruka YAMAZAKI, Toshiya YOSHIDA
Forest ecology and management ( Forest Ecology and Management ) 393 81 - 88 2017.06 [Refereed]
Academic Journal Multiple authorship
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.
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YAMAZAKI Haruka, KUNISAKI Takashi
Journal of the Japanese Forest Society ( Japanese Forest Society ) 96 ( 2 ) 117 - 120 2014.07 [Refereed]
Academic Journal Multiple authorship
We evaluated canopy opening, which was expected to be a critical factor affecting snow damage, using Voronoi polygon area to explain the occurrence of snow accretion damage in an old planted Cryptmeria japonica stand in December2010. We performed a logistic regression analysis using slope gradient, height: diameter at breast height(DBH)ratio, tree form class, and Voronoi polygon area as explanatory variables. Trees on the slope site that had a larger Voronoi polygon area and a greater height: DBH ratio tended to be more damaged by snow. The odds ratio based on the difference in average height: DBH ratio between trees on the slope site with and without snow damage was1.21, and the odds ratio based on the difference in the average Voronoi polygon area between trees on the slope site with and without snow damage was1.40. In conclusion, canopy opening in dense plantations of old sugi does not prevent snow accretion damage; thus, height: DBH ratio and canopy opening are critical factors affecting snow damage.
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KUNISAKI Takashi, SEKIHARA Fumiko, YAMAZAKI Haruka, SHIRAHATA Manabu
Bulletin of the Iwate University Forests ( Faculty of Agriculture, Iwate University ) 45 37 - 45 2014.06 [Refereed]
Others Multiple authorship
We selected principal variables correlated to the leaf mass index of young and old Pinus densiflora trees. Crown-and stem-related variables were used in ordinal logistic regression procedures to model the leaf mass index of individual trees in young and old pine stands. Ordinal logistic regression analysis revealed that the Akaike information criterion (AIC) of models using the height, branch height, and live crown ratio as predictor variables were less than those of models without these variables as predictor variables in the young pine stand. The branch height and live crown ratio were positively correlated with the leaf mass index of the young individual trees. However, the AIC of the null model was the least of the 31 models examined in the old pine stand.