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961.
In order to develop a fireproof wooden material, the synergic effect of fire-retardant chemicals and wood coatings was studied.
The fire performance was evaluated by cone calorimeter. Impregnation of fire retardants including polyphosphatic carbamate,
and ceramic coatings including alkoxy metal salt improved the fire performance of wooden materials. This treatment made it
possible to meet the guidelines for fire performance of noncombustible materials in Japan. In addition to the vacuum-pressure
impregnation treatment, hot-and-cold-bath impregnation treatment is an effective way to develop fire-retardant wood by impregnating
fire retardant and ceramic coating. The weatherability of the developed material was also investigated. The ceramic coating
was resistant to light and moisture.
Part of this report was presented at 54th Annual Meeting (Sapporo, August 2004) and the 55th Annual Meeting (Kyoto, March
2005) of the Japan Wood Research Society 相似文献
962.
Development, manufacture and application of Beta-Cypermethrin aqueous capsule suspension 总被引:1,自引:0,他引:1
LANGZi-jian SUYuan-ji WANGZhi-ying ChenLi-ping 《林业研究》2004,15(3):218-222
The optimal formula of Beta-Cypermethrin aqueous capsule suspension was screened out through the experiment,preparation and manufacture of basic formulas, which has no sedimentation, suspended drops of oil, peels and agglomerating and the diameter of capsule is in range of 10-30μm, conformed to the technical requirement. The aftereffect of the 3.3% Beta-Cypermethrin aqueous capsule suspension which was manufactured according to the optimal formula was up more than 25 days. The experiments on controlling the larvae of Dendrolinmus superans Butler and the adults of Xylotrechus rusticus L were carried out with different concentrations of this chemical. The death rate reached 80% when 250 times solution of the chemical was sprayed on stem to control the larvae of D. superans. For control of the adults of X. rusticus, 200, 400 and 600 times solution of the chemical were applied and their control effects (death rate) reached 85.23%, 74.21% and 66.59% respectively. Two kinds of solution (200 times and 300 times) of the chemical were used to control the larvae of D. superans in large area, and the control effect for both concentrations was over 90%. 相似文献
963.
Emma Wilhelmson Dianne Staal Wästerlund Lage Burström Per-Olof Bylund 《Small-Scale Forestry》2005,4(4):427-435
Little is known about the extent of work-related accidents occurring during the performance of forestry work by the non-industrial private forest owner or their assistant (hereafter called self-employed NIPF). The absence of an effective accident registration system largely excludes this group from accurate representation in official statistics. In this study, data from 1996 to 2001 were collected from hospital injury records managed by the Umeå Accident Analysis Group at the University Hospital in Umeå. During that period, it was found that 485 persons in the Umeå region were given medical attention due to injuries possibly acquired during self-employed forestry work. Questionnaires about the accidents were sent to each of the 485 injured persons and 80% were returned. Responses revealed that 225 of the respondents were injured during self-employed forestry work. Out of these, 81% performed fewer than 31 days of forestry work annually. Due to the injury, 29% had been on sick leave for some period of time and 42% had persistent symptoms. On average, each injury led to 13 days of sick leave and 24 hours of institutional care. Firewood production was shown to be a key factor behind the large number of accidents for self-employed NIPF. Further studies on the lack of knowledge about how the work should be done and conscious risk taking should be considered as an important link to the development of effective accident prevention strategies. 相似文献
964.
Alexandre Behling Carlos Roberto Sanquetta Ana Paula Dalla Corte Sylvio Péllico Netto Aurélio Lourenço Rodrigues Bráulio Otomar Caron Augusto Arlindo Simon 《林业研究》2016,27(6):1211-1217
The amount of photosynthetic radiation intercepted by a crop is a function of the incident solar radiation on the plants, the leaf area index (L AI), and the light extinction coefficient (k). We quantified L AI and k in stands of black wattle (Acacia mearnsii De Wild.) over a 7-year growth cycle at two locations in the state of Rio Grande do Sul, Brazil. Our study was conducted in commercial stands in agroecological regions with high densities of black wattle plantations. L AI was calculated as the ratio between the leaf area of a tree and its planting space, and k was derived from Beer’s law. L AI depends on the planting site and stand age. Between the two sites, the L AI was similar over time, the amount of variation differed. Values of k depended only on stand age, with the highest average observed for stands up to 5 years old. The trend of k during the plantation cycle was inversely proportional to L AI and was correlated with L AI, leaf area, leaf dry mass, canopy volume, height, branches dry mass, total dry mass, and crown diameter. 相似文献
965.
Tea tree oil is extracted from the leaves and twigs of Melaleuca alternifolia (Maiden & Betche) Cheel, and it is widely used in medicines, food preservatives, cosmetics and health care products. Traditional propagation of M. alternifolia from seeds does not necessarily transfer the desired characteristics from their mother trees, the seedlings are not uniform, and the multiplication rate from cuttings is relatively low. For these reasons, it is necessary to develop tissue culture techniques for this species. This study showed that an efficient explant initiation medium for M. alternifolia was MS 1/2 + BA 0.6 mg L?1 + NAA 0.1 mg L?1 + sucrose 30 g L?1, which yielded a 75.9 % initiation rate. An efficient multiplication medium was MS + BA 0.3 mg L?1 + NAA 0.15 mg L?1 + sucrose 30 g L?1, which yielded a 4.3 multiplication rate and 3.2 cm shoot length. The rooting medium was MS 1/2 + IBA 0.1–0.25 mg L?1 + sucrose 15 g L?1, which yielded a 100 % rooting rate, 2.94–3.32 roots per individual and 1.36–1.44 cm root length. Local red-core soil was suitable as a transplant medium, and yielded 98 % survival. This study improved the tissue culture technique for mass-propagation of M. alternifolia, enabling the production of high quality plants for market. 相似文献
966.
Walter Seidling 《European Journal of Forest Research》2007,126(4):529-544
Crown transparency estimates of Scots pine, Norway spruce, common beech, pedunculate and sessile oak, annually surveyed between
1990 and 2004 within a grid over Germany, provide a suitable response variable to study drought effects on forest trees. Major
climatic factors, available on a monthly basis as plot-specifically interpolated values and parameters of site and stand conditions,
biotic and other relevant factors were used as predictors in different cross- and length-sectional, and longitudinal models.
Stand age is a considerable and most constant driver of crown transparency in all species. Pine, spruce and beech responded—mainly
with a delay of 1 year—with some foliar loss in areas where there was a surplus of temperature after the generally hot and
dry summer of 2003. Parallel time-series analyses delivered species-specific geographic large-scale patterns with delayed
or recent precipitation deficits or temperature surpluses. Even if beech is partly responding in current years with leaf loss
towards precipitation surpluses, defoliation is especially high 1 year after hot summers, partly a result of high seed sets
after such summers. Crown condition of oak responds in dry and warm areas according to the drought stress hypothesis, however,
in cool and wet mountainous ranges oak responds after wet summers with higher defoliation. Longitudinal approaches revealed
for all 4-tree species significant relationships between crown condition and deviations from the long-term means of temperature,
precipitation but also global radiation and wind speed. Results do not always match the drought stress hypothesis, however,
this is not to expect considering the heterogeneous site, stand and climatic conditions across Germany. Complex interactions
of climatic and biotic factors also impede simple relationships. Soil-related clusters reveal higher sensitivity of spruce
and beech towards climatic drought factors on more acid soils with thin humus layers. Also clusters constructed from plot-specific
courses of defoliation reveal groups with rather closer relationships like a group of pine plots in the Oberpfalz, which seems
to be especially sensitive to summer drought. 相似文献
967.
A dendrochronological technique was used to investigate canopy recruitment of beech (Fagus engleriana Seem.) trees in western Hubei Province of Central China by identifying growth releases through gap formation. The results
indicated that 83% and 17% of the canopy trees regenerate in gaps and the understory, respectively. Radial growth analyses
demonstrated that there are three modes for beech regeneration and canopy recruitment: (1) gap origin without suppression;
(2) gap origin with period(s) of suppression; and (3) understory origin. Multiple periods of release and suppression imply
that beech regeneration and canopy recruitment are very sensitive to gap formation. 相似文献
968.
This study develops an analytical method that enables the simulation of the deformation of timber-framed plywood panel dome
structures, of which strength is largely governed by the rigidity of joints. A hybrid truss structure model was employed to
analyze this structure. In this model, we aimed to incorporate the mechanical properties of bolted and nailed joints, which
were employed to build the structures, although the present investigation focused on the deformation characteristics of a
dome in which the panel elements were connected mutually by elastic springs. The results of the theoretical analysis are compared
with those obtained by experiments. The simulated results were found to be in good agreement with the results of the experiments
under similar loading conditions. 相似文献
969.
Won-Joung Hwang S. Nami Kartal Yuji Imamura Kunio Tsunoda Katsumi Shinoda 《Journal of Wood Science》2007,53(4):332-338
This study describes a laboratory evaluation of the efficacy of two alkylammonium compounds [didecyldimethylammonium tetrafluoroborate
(DBF) and didecyldimethylammonium chloride (DDAC)] when applied via vacuum impregnation or superficial treatment. Treated
wood specimens were tested for their termite and microbial resistance under controlled laboratory conditions. The higher chemical
retentions were needed to suppress the feeding by Coptotermes formosanus ≦3% mass loss in the multichoice test than in the no-choice test. The DBF and DDAC retention levels necessary to meet the
performance requirement ≦3% mass loss after 12-week fungal exposure varied with wood species. The retention level of 3 kg/m3 for DBF and DDAC was generally high to keep the nondurable wood species free of decay. Although there was no difference between
DBF and DDAC in the efficacy against decay and termite attack, the former slightly outperformed the latter as an antimold
and antisapstain agent. 相似文献
970.
Walter Sekot 《European Journal of Forest Research》2007,126(4):481-494
Within the European Union there exist three different frameworks for forest accounting at the national level. For purposes
of the national accounts, the regulations of the European System of Integrated Economic Accounts (ESA) have to be observed.
They require a distinction between forestry and logging and provide specific guidelines for the valuation of standing timber.
In recognition of the special character of forests and forestry production, two satellite accounts are devoted to forestry:
the Economic Accounts for Forestry (EAF) and the European Framework for Integrated Environmental and Economic Accounting for
Forests (IEEAF). Although they were designed as complementary to the national accounts and refer to the same basic methodologies,
the guidelines for forest accounting provided by the three manuals are not fully compatible. Just recently, a further integration
and harmonization of the concepts for forest accounting has been proposed. Austria has implemented the valuation of the increment
as an output of forestry as requested by ESA and produces the EAF tables on a regular basis. The possibilities for extending
forest accounting to natural resource accounts for standing timber and the IEEAF have been investigated in terms of pilot
studies. The Austrian experiences and results exemplify the problems and possible solutions associated with the adoption of
the different European schemes. Data deficits and valuation issues restrict the significance of respective results to some
degree, especially as regards forestry-specific extensions of the accounting schemes. 相似文献