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1.
Toru Kohama Nobuya Mizoue Satoshi Ito Akio Inoue Kotaro Sakuta Hiroyuki Okada 《Journal of Forest Research》2006,11(4):235-242
We examined the extent to which direct and indirect measures of light and microsite conditions could explain variation in
tree height and diameter at the base of 6-year-old Cryptomeria japonica trees planted in a group selection opening of about 0.32 ha on a steep slope at Shiiba, Miyazaki Prefecture, southern Japan.
We first used the gap light index (GLI) and soil thickness (ST) as directly measured indices. For an indirect measure of light, we used a between-cohort competition index (BCI) estimated from the position and total height of residual trees. For indirect measures of microsite, we examined topographic
indices (slope, plan and profile curvature, average slope gradient, and relative elevation) derived from digital elevation
models (DEMs) with different resolutions ranging from 2 to 10 m. The multiple linear regression using GLI and ST explained about 45% of variation in tree size, while simple regression using only GLI explained about 35%. The contribution of ST was about half of GLI. The multiple regressions using BCI and the topographic indices did not explain any more variation than using BCI alone (R
2 of about 0.26). We conclude that microsite conditions with shallower soil and steeper slope have negative effects on tree
growth in group selection openings, although the relative importance is smaller than light conditions. More comprehensive
studies considering several openings with more heterogeneous topography including different species are needed to generalize
our growth prediction using the indirect measures, which are useful for practical forest management. 相似文献
2.
In the tropical canopy tree, Dryobalanops aromatica Gaertn. f., upper-canopy leaves (UL) develop under sunlit conditions but are subjected to self-shading within the crown as they age. In contrast, lower-canopy leaves (LL) are exposed to uniform dim light conditions throughout their life span. By comparing leaf morphology and physiology of UL and LL, variations in leaf characteristics were related to leaf age and self-shading. Mass-based chlorophyll (chl) concentration and the chlorophyll/nitrogen (chl/N) ratio were lower and the chl a/b ratio was higher in UL than in LL. In UL, the chl/N ratio gradually increased and the chl a/b ratio gradually decreased with leaf aging, whereas these ratios remained unchanged with leaf age in LL. The effective quantum yield of photosystem II (PSII) (DeltaF/F(m)') at a given irradiance remained unchanged with leaf age in LL, whereas DeltaF/F(m)' changed with leaf age in UL. These data indicate N reallocation within the leaves from carbon fixation components to light harvesting components and a dynamic regulation of photochemical processes of PSII in response to increased self-shading of UL. Despite the difference in light environment with leaf age between UL and LL, maximum photosynthetic rates and nitrogen-use efficiency decreased with leaf aging in both UL and LL. Constancy in the chl/N ratio with leaf age in LL indicated that the decrease in photosynthetic capacity was caused by effects other than shading, such as leaf aging. We conclude that N reallocation and acclimation of PSII to self-shading occurred even in mature leaves, whereas the change in photosynthetic capacity with leaf age was more conservative. 相似文献
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4.
Morio Imada Takashi Kunisaki Nobuya Mizoue Yukio Teraoka 《Journal of Forest Research》1997,2(2):89-93
A spacing experiment for Japanese oak (Quercus mongolica var.grosseserrata) with Nelder's design have been studied at the Kyushu University Forest in Hokkaido, since 1975. The oak seedlings were planted
according to systematic spacings which were 20 levels varying gradually from 40,816 to 1,086 seedlings per hectare with concentric
circular arcs (22 in number) and spokes (41 in number). In 1992 when the planted oak seedlings were 18-year-old, DBH, crown
diameter, total height and clear length of the survival trees were measured. Based on the results obtained from analyzing
the relationships between planting density and the mean values of each block, the optimum planting density should be 7,241
seedlings per hectare.
The title is tentative translation from the original Japanese title by the authors of this paper. 相似文献
5.
Tsuyoshi Kajisa Takuhiko Murakami Nobuya Mizoue Shigejiro Yoshida 《Journal of Forest Research》2007,12(6):435-441
Our objective was to investigate the differences in the spectral trajectory of the LANDSAT Thematic Mapper with stand volume
development between Japanese larch (Larix kaempferi) and Japanese oak (Quercus mongolica var. crispula) in the experimental forest of Kyushu University, Hokkaido, Japan. We used nonlinear regression and a categorical variable
to investigate the relationship between spectral reflectance factor and stand volume for each forest type. This research showed
that the reflectance factor of Japanese larch and Japanese oak reached saturation and that both forest types had different
spectral trajectories with stand development. In addition, we found that middle of development stage (stand volume was between
100 and 200 m3/ha) of each forest type had similarity in reflectance factor. 相似文献
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7.
Tetsuji Ota Tsuyoshi Kajisa Nobuya Mizoue Shigejiro Yoshida Gen Takao Yasumasa Hirata Naoyuki Furuya Takio Sano Raul Ponce-Hernandez Oumer S. Ahmed Heng Sokh Vuthy Ma Eriko Ito Jumpei Toriyama Yukako Monda Hideki Saito Yoshiyuki Kiyono Sophal Chann Nang Ket 《Journal of Forest Research》2015,20(6):484-492
8.
We examined the contribution of rubberwood to the timber export markets of Malaysia and Thailand. In Malaysia, rubberwood
has grown from 26% of total exported wood products in 1998 to 35% in 2007. A high proportion of furniture products (80%) is
rubberwood, whereas the contribution of rubberwood to other wooden products is less than 20%. Only 10% of sawn timber and
logs is rubberwood. In Thailand, rubberwood contributes to around 60% of total exported wood products, arising from a high
share of not only furniture products (70%) but also other wood products (around 50%) and sawn timber and logs, which have
increased in share from 40% in 1998 to 79% in 2007. We conclude that the high proportion of rubberwood products in the wood
export markets of these two countries is a result of: (1) scarcity of raw wood materials because of strict controls on the
logging of natural forests; and (2) governmental support to rubberwood production, including financial support to rubber planters
and technical assistance to downstream timber processors. 相似文献
9.
Akira Shigematsu Nobuya Mizoue Kumiko Ide Kakada Khun Muthavy Pheng Shigejiro Yoshida Katsuhisa Kohroki Noriko Sato 《New Forests》2011,42(2):149-162
We estimated the production of rubberwood from 1996 to 2011 in Cambodia. We employed data from interview surveys with three
rubberwood processing companies and statistics from estate rubber plantations and wood retailing companies. The result was
that the end use of rubberwood in Cambodia was the sawntimber products, being exported to Vietnam and China. The yield rate
from rubberwood stumpage into sawn timber was between 11.6 and 14.9%, closely matching the rates of Malaysia and Thailand.
The average production of rubberwood roundwood from 1996 to 2011 was 254,697 m3/year, of which sawn timber as well as residuals in secondary processing was 84,559 and 170,138 m3/year, respectively. Although the timber production of Cambodia has declined sharply due to the strict restriction of natural
forest logging, rubberwood could explain more than 60% of the domestic industrial roundwood production from 2000. We suggest
the necessity of monitoring the expansion of rubber plantations in new rubber producing countries and linking the rubberwood
production with the regional wood resource management. 相似文献
10.
Toshio Kobayashi Yutaka Oshima Yasuhiro Tsubokura Takako Muroi Shozo Ajimi Makoto Nakai Kenji Kawaguchi Takeshi Sasaki Naohide Shinohara Nobuya Imatanaka 《Journal of toxicologic pathology》2021,34(1):43
Occupational exposure to nickel oxide (NiO) is an important cause of respiratory tract cancer. Toxicity is known to be associated with the dissociated component, i.e. nickel (II) ions. To address the relationship between physicochemical properties, including solubility in artificial lysosomal fluid, of NiO and time-course changes in the pulmonary response, we conducted an intratracheal instillation study in male Fischer rats using four different well-characterized NiO products, US3352 (NiO A), NovaWireNi01 (NiO B), I small particle (NiO C), and 637130 (NiO D). The NiOs were suspended in purified water and instilled once intratracheally into male F344 rats (12 weeks old) at 0 (vehicle control), 0.67, 2, and 6 mg/kg body weight. The animals were euthanized on days 3, 28, or 91 after instillation, and blood analysis, bronchoalveolar lavage fluid (BALF) testing, and histopathological examination were performed. The most soluble product, NiO B, caused the most severe systemic toxicity, leading to a high mortality rate, but the response was transient and surviving animals recovered. The second-most-soluble material, NiO D, and the third, NiO A, caused evident pulmonary inflammation, and the responses persisted for at least 91 days with collagen proliferation. In contrast, NiO C induced barely detectable inflammation in the BALF examination, and no marked changes were noted on histopathology. These results indicate that the early phase toxic potential of NiO products, but not the persistence of pulmonary inflammation, is associated with their solubility. 相似文献