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971.
Comparison and early selection of new clones in <Emphasis Type="Italic">Populus tomentosa</Emphasis>
In our study, two experimental plantations, respectively, with 24 and 32 new clones of P tomentosa, were established in Weixian County, Hebei Province and Wuzhi County, Henan Province using a completely randomized block design. A comparative study was conducted on the continuous 5-year-old height and diameter at breast height (DBH) of new clones in the two plantations. As well, based on genetic correlation over the years of testing of these clones, a preliminary study of early selection was carried out. Results indicate that the growth traits of the new clones in Weixian were better than those in Wuzhi. The traits show weak correlation between the two plantations. In some stands, the height, DBH and seedling volume of 5-year-old clones presented statistically significant differences among clones. In both plantations, the new clones showed over 0.6 repeatability of height, DBH and volume, as well as larger coefficients of variation (CV). The fact that these clones achieved the largest repeatability and CV in the second year suggests that these traits are highly controlled by heredity. Thus, based on the growth traits of the second year, the new clones B305, B307, B303, H75, BT18, BT17 and 21J-1 were considered suitable in Weixian. In Wuzhi, the new clones had variable repeatability and CVs in various years and their correlation of growth traits among different years was not high. We conclude that early selection of new clones was not feasible in Wuzhi. 相似文献
972.
Different leaching media composed of watersoluble extracts from Sakhalin fi r, Japanese cedar, and Japanese larch heartwoods
and of taxifolin were used to characterize leaching of the C12 and C14 homologues of benzalkonium chloride from treated wood.
The leaching medium of Sakhalin fi r extract moderately accelerated the leaching rates of the two homologues. Japanese cedar
extract accelerated the leaching of the C12 homologue at a similar rate and that of the C14 homologue at a higher rate. Japanese
larch extract remarkably accelerated the leaching rates of both homologues, particularly that of the C14 homologue. Thus,
the leaching rate of the C14 homologue was higher than that of the C12 homologue with the Japanese cedar and larch extracts.
The media of taxifolin, a major phenolic extractive of Japanese larch, preferentially accelerated the leaching rate of the
C14 homologue. The amounts of phenolic compounds in the different leaching media were in the following order: Japanese larch
> Japanese cedar > Sakhalin fi r. These results indicate a relationship between the amount of phenolic compounds and the leaching
rates of the two homologues. 相似文献
973.
This study examined the effects of contact with wood on the living human body using a physiological index and subjective evaluation.
Consecutive blood pressure measurements were used as the physiological index, and sensory evaluation using the semantic differential
(SD) method was used for subjective evaluation. Consideration was also given to cases in which materials were cooled and heated
as well as kept at room temperature, to eliminate the effects of heat flux due to differences in thermal conductivity between
wood and other materials. It was found that contact with wood produced coarse/natural sensations, with no associated increase
in systolic blood pressure. Contact with cold wood created subjectively dangerous/uncomfortable but still coarse/natural sensations,
also with no associated increase in blood pressure; therefore, there was no correspondence between subjective evaluation and
physiological responses. Contact with aluminum kept at room temperature and cold acrylic plastic created flat/artificial and
dangerous/uncomfortable sensations, with an associated significant increase in blood pressure; thus, there was a close correlation
between subjective evaluation and physiological responses. It was therefore concluded that contact with wood, unlike artificial
materials such as aluminum, induces no physiological stress even when kept at room temperature or cooled.
Part of this report was presented at the 48th Annual Meeting of the Japan Wood Research Society in Shizuoka, April 1998 相似文献
974.
Takanori Imai Sousuke Inoue Naomi Ohdaira Yasuyuki Matsushita Rie Suzuki Mariko Sakurai José Manoel Henriques de Jesus Salete Kiyoka Ozaki Zenesio Finger Kazuhiko Fukushima 《Journal of Wood Science》2008,54(6):470-475
Heartwood extracts from Amazonian trees cumaru-ferro (Dipteryx odorata), jatoba (Hymenaea courbaril), and guarita (Astronium lecointei) exhibit antioxidant activities comparable with that of α-tocopherol, a well-known antioxidant. This article reports the characterization of the antioxidant compounds in the extracts
of the three heartwoods. Silica gel column chromatography of the cumaru-ferro EtOAc extract yielded (−)-(3R)-7,2′,3′-trihydroxy-4′-methoxyisoflavan and (+)-(3R)-8,2′,3′-trihydroxy-7,4′-dimethoxyisoflavan. Silica gel column chromatography followed by preparative high-performance liquid
chromatography of the jatoba EtOAc extract yielded (−)-fisetinidol and (+)-trans-taxifolin. Chemical structures were assigned using electron-ionization mass spectrometry, 1H and 13C nuclear magnetic resonance (NMR) spectroscopy including nuclear Overhauser effect spectroscopy (NOESY), as well as optical
rotation and circular dichroism. Gas chromatography-mass spectrometry demonstrated that the isolated compounds were predominant
in the EtOAc extracts. In the guarita EtOAc extract, catechin and gallic acid were identified by comparing their retention
times and mass fragmentation patterns with those of authentic samples. Antioxidant activity determined by the 1,1-diphenyl-2-picrylhydrazyl
assay demonstrated that all these compounds had activities comparable with that of α-tocopherol.
Part of this report was presented at the 57th Annual Meeting of the Japan Wood Research Society, Hiroshima, August 2007 相似文献
975.
Toru Taniguchi Yasunori Ohmiya Manabu Kurita Miyoko Tsubomura Teiji Kondo Yong Woo Park Kei’ichi Baba Takahisa Hayashi 《Journal of Wood Science》2008,54(5):408-413
We performed biosafety assessments of transgenic poplars prior to field trials. Constitutive expression of the Aspergillus aculeatus xyloglucanase in Populus alba increased the cellulose content and specific gravity of its stem, the leaves of which were visibly greener, thicker, and
smaller than those of the wild-type plant. Although the young transgenic poplars grew faster than the wild type in a growth
chamber, there was no distinguishable difference in growth between the poplars when they were placed in a special screened
greenhouse. Allelopathic tests showed that the transgenic poplars do not produce harmful substances. Based on all the biosafety
assessments and the scientific literature on poplar species, we came to the conclusion that transgenic poplars probably do
not disturb the biological diversity of the surrounding environment, even when they are submitted to field trials. 相似文献
976.
Wook Kang Chun-Won Kang Woo Yang Chung Chang-Deuk Eom Hwanmyeong Yeo 《Journal of Wood Science》2008,54(5):343-348
This study was undertaken to estimate the effect of openings between cell walls on combined bound water and water vapor diffusion
in wood. Using a newly developed model, the radial and tangential moisture diffusion coefficients can be predicted depending
on the opening area. The new model explicitly involves a term for water vapor diffusion through the openings, as well as a
term for the combined diffusion of bound water and water vapor. A classical model developed by Stamm and Choong had higher
longitudinal moisture diffusion coefficients than that in the parallel model at higher moisture content, which is inconsistent
with the Wiener bound rule. The new model suggested in this article is useful for analyzing the experimental results and understanding
the variability of the diffusion coefficients. 相似文献
977.
T. Sariyildiz E. Akkuzu M. Küçük A. Duman Y. Aksu 《European Journal of Forest Research》2008,127(5):429-440
This study investigated the effects of Ips typographus (L.) damage on initial litter quality parameters and subsequent decomposition rates of oriental spruce tree species [Picea orientalis (L.) Link]. The needle litter was collected from highly damaged, moderately damaged and control stands on two aspects (north
and south) and two slope position (top and bottom) on each aspect. The litter was analyzed for initial total carbon, lignin
and nutrient (nitrogen, phosphorus, potassium, calcium, magnesium and manganese) concentrations. The variability in nitrogen
and calcium concentrations and ratios of C:N, lignin:N and lignin:Ca was significantly affected by the insect damaged levels.
While nitrogen concentrations in needle litter increased with increasing insect damage (and consequently the ratios of C:N
and lignin:N decreased), calcium concentrations decreased (and consequently the ratio of lignin:Ca increased). Aspect and
slope positions explained most of the variability in carbon, lignin, phosphorus, potassium, magnesium and manganese concentrations
and lignin:P ratio between all studied stands. Litter decomposition was studied in the field using the litterbag technique.
The litter from highly damaged stands showed highest decomposition rates followed by moderately damaged and control stands.
The mass loss rates were significantly positively correlated with initial nitrogen concentration and negatively with C:N and
lignin:N ratios. The effects of microclimate resulting from canopy damage on litter decomposition was also examined at the
same time using standard litter with the same litter quality parameters, but they showed no significant differences among
the insect damage levels indicating that alteration of the litter quality parameters produced by I. typographus damage played a more important role than altered microclimate in controlling needle litter decomposition rates. However,
changes in microclimate factors due to topography influenced decomposition rates. 相似文献
978.
Temporal variation of leaf area index (LAI) in two young Norway spruce stands with different densities was monitored during
eight consecutive growing seasons (1998–2005). We focused on: (1) LAI dynamics and above-ground mass production of both spruce
stands and their comparison, (2) leaf area duration (LADU), crop production index (CPI) and leaf area efficiency (LAE) evaluation,
and (3) thinning impact on the above-mentioned parameters. Also, we tried to deduce the most effective LAI value for the Norway
spruce forest investigated. The LAI values of both spruce stands showed a typical seasonal course. To describe the LAI dynamics
of the stand, we recommend taking LAI measurements within short time intervals at the time of budding and needle expansion
growth (i.e., in early spring) and close to the LAI peak, when the twig growth has been completed. The reason was that after
reaching the seasonal maximum, no significant differences between subsequently obtained values were found in the following
2 months. Therefore, we recommend this period for the estimation of seasonally representative LAI values, enabling the comparison
of various spruce stands. The maximum hemi-surface LAI value reached 12.4. Based on our results, the most effective LAI values
for maximum above-ground biomass production were within the range of 10–11. We found an LAI over these values to be less effective
for additional production of above-ground biomass. In forest practice, thinning intensity is mostly described by percentage
of stocking reduction. We want to show that not only thinning intensity, but also the type of thinning is important information.
The type of thinning significantly affected the stand above-ground biomass increment, canopy openness, stand LAI and LAI efficiency.
The stimulating effect of high-type thinning was observed; the LAE as well as the CPI increased. Low-type thinning had no
such effects on LAE increments compared to the high-type thinning with similar intensity.
相似文献
979.
Responses of the endemic leguminous shrub Bauhinia faberi var. microphylla, to various soil water supply regimes were studied in order to assess water stress tolerance of seedlings. Two-month-old
seedlings were grown under water supply regimes of 100, 80, 60, 40, and 20% water field capacity (FC), respectively, in a
temperature and light-controlled greenhouse. Plant height and leaf number were measured monthly over a 4-month period, while
water use (WU), water-use efficiency (WUE), leaf relative water content (RWC), biomass production and its partitioning were
recorded at the end of the experiment. Seedlings exhibited the greatest biomass production, height, basal diameter, branch
number, leaf number, and leaf area when soil content was at 100% FC, and slightly declined at 80% FC. These parameters declined
significantly under 60% FC water supply, and severely reduced under 40 and 20% FC. RWC, WU and WUE decreased, while the ratio
of root mass to stem mass (R:S) increased in response to decreasing water supply. Water stress caused leaf shedding, but not
plant death. The results demonstrated that B. faberi var. microphylla seedlings could tolerate drought by reducing branching and leaf area while maintaining a high R:S ratio. However, low dry
mass and WUE at 40 and 20% FC suggested that the seedlings did not produce significant biomass under prolonged severe water
deficit. Therefore, before introducing B. faberi var. microphylla in vegetation restoration efforts, water supply above 40% FC is recommended for seedlings to maintain growth. 相似文献
980.
Community participation in a social forestry program in Central Java,Indonesia: the effect of incentive structure and social capital 总被引:1,自引:0,他引:1
Tri Lestari Djamhuri 《Agroforestry Systems》2008,74(1):83-96
A new social forestry program has been implemented in Java to overcome encroachment of state forests. In this program, the
state and local communities jointly manage the state forests and share the benefits of increased forest resource stock and
flow as a result of the management. This article aims to investigate the complete incentive structure of the social forestry
program and how the incentive structure changes community member participation in forest management. Property rights transfers
and economic analyses were employed to analyze the incentive structure. We conclude that although incomplete, the transfer
of rights from the state to the community members is a useful approach toward establishing an effective incentive structure
and provides a net gain to the community members. The extent of community participation, however, depends not only on the
incentive structure but also on the social capital that exists in the community. 相似文献