Chemical analysis of the product in acid-catalyzed solvolysis of cellulose using polyethylene glycol and ethylene carbonate     

Tatsuhiko Yamada  Masako Aratani  Satoshi Kubo  Hirokuni Ono 《Journal of Wood Science》2007,53(6):487-493

Degradation and decomposition of cellulose were studied in an acid-catalyzed solvolysis treatment of biomass using polyethylene glycol (PEG) and ethylene carbonate (EC). The solvolysis reaction was followed by a typical reaction system of wood liquefaction that uses sulfuric acid catalyst at 140° or 150°C at atmospheric pressure. The methods of fractionation and chemical analysis of the degraded cellulose in the solvolyzed product are discussed. The solvolyzed product was separated into several fractions, and they were hydrolyzed to release glucose and levulinic acid to determine the quantity of glucosides and levulinates in the solvolysis product. The data clearly showed that the solvolysis reaction had the same mechanism when using PEG or EC. Degradation of cellulose leads to the formation of glucosides, which then decompose, resulting in a levulinic acid structure, and producing a water-insoluble fraction. The conversion rates of both glucosides and levulinates strongly depend on the reaction conditions of the solvolysis. In particular, EC promotes faster conversion of the reactions. The method discussed here is a chemical analytical technique for characterization of the products of wood liquefaction.  相似文献   

Mechanical properties of wood in an unstable state due to temperature changes,and analysis of the relevant mechanism IV: effect of chemical components on destabilization of wood     

Yue Wang  Ikuho Iida  Kazuya Minato 《Journal of Wood Science》2007,53(5):381-387

In order to investigate the effects of chemical components and matrix structure on the destabilization of quenched wood, we examined the physical and mechanical properties of steam-treated wood, hemicellulose-extracted wood, and delignified wood, which were treated at different levels. For steam-treated and hemicellulose-extracted wood,the relative relaxation modulus of the quenched sample was lower than that of the respective control sample. For delignified wood, the relative relaxation modulus fell with weight loss and reached a minimum value at a certain weight loss, and subsequently increased significantly. The hygroscopicity of all treated samples changed slightly by steaming, whereas increased with removing the component. More-over, the average volumetric swelling per 1% MC at 100% relative humidity (RH) was less than at 75% RH and 93% RH for component-removed wood. It was clear that a void structure existed. As a result, the destabilization evaluated by the fluidity (1 - E _t/E ₀) of steam-treated wood was influenced by the amount of adsorbed water. For component-removed wood, destabilization increased temporarily at lower weight loss because of nonuniform cohesive structure. At high weight loss, destabilization will decreased because capillary-condensed water gathered in the voids and obstructed the motion of adsorbed water. However, the destabilization of all treated wood changed less than that of chemically modified wood.  相似文献   

Differences in spectral trajectory with stand volume development between Japanese larch and Japanese oak in Hokkaido,Japan     

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   

Characterization of proanthocyanidin in hot water extract isolated from <Emphasis Type="Italic">Pinus radiata</Emphasis> bark     

Chang Sub Ku  Sung Phil Mun 《Wood Science and Technology》2007,41(3):235-247

Proanthocyanidins (PAs) in the hot water extract prepared from Pinus radiata bark were isolated by a Sephadex LH-20 chromatography. The PAs were characterized using UV/Visible, FT-IR and ¹³C nuclear magnetic resonance (NMR) spectroscopic techniques, matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry (MS), and gel permeation chromatography (GPC) analysis. Bate-Smith acidic alcoholysis and FT-IR spectrum of the PAs indicated the predominant presence of the procyanidin (PC) structure. The ¹³C NMR spectrum revealed that the PAs comprise PC (94%) together with a small amount of prodelphinidin (PD, 6%), and also that they contain the higher trans configuration rather than the cis configuration of C2–C3. The MALDI-TOF MS results obviously proved the presence of PD units, but the maximum degree of polymerization (DP) was limited to octamer. The average molar mass (Mw, Mn), polydispersity (Mw/Mn), and DP of the pine bark PAs were 3,800 (Mw), 1,200 (Mn), 3.2, and 13, respectively.  相似文献   

PEG bulking of wood cell walls as affected by moisture content and nature of solvent     

Dragica Jeremic  Paul Cooper  Darrick Heyd 《Wood Science and Technology》2007,41(7):597-606

Movement of polyethylene glycol (PEG) 1000 from wood cell lumens into adjacent cell walls was studied for different cell wall moisture contents (MCs) and PEG solvents; relative amounts of PEG that penetrated into the cell walls were estimated by Raman microscopy. It was shown that samples treated with PEG from chloroform solution adsorb less PEG than samples treated with PEG-water solution even in the case of samples with open cell wall structure near fibre saturation point MC. Reconditioning of PEG-chloroform treated samples at high relative humidities enhanced PEG bulking of cell walls, but not to the maximum amounts observed with PEG-water treatments. Raman microscopy was a useful tool for estimating relative PEG amounts in the cell walls.  相似文献   

Contamination and browning in tissue culture of Platanus occidentalis L.     

Tao Feng-jie  Zhang Zhi-yi  Zhou Jun  Yao Na  Wang Dong-mei 《中国林学(英文版)》2007,9(4):279-282

Twigs of 2–3-year-old Platanus occidentalis L. were used as experimental material to find the causes for the contamination and browning in the initial stages of tissue cultures. To compare the degree of browning of explants picked off from different growing seasons, the experimental material was excised from trees on each of the first ten days in January, March, May and July, 2006. The results indicated that the contamination and browning rates of the material cut off in January (14.2% and 30.6%, respectively) and March were somewhat lower than those in July. The pretreatment of soaking the explants in different anti-oxidants and absorbents at the same time could diminish some side effects. The pretreatment of using 10 g·L–1 vitamin C reduced the contamination and brown-ing rate effectively. An orthogonal experiment showed that the optimal factor and level arrangement is 0.5 mg·L–1 BA, 2.0 g·L–1 ac-tive carbon and 1.5 g·L–1 PVP which resulted in a browning rate of only 16.5%. In general, sampling period, physical properties and pretreatment of explants are the main factors responsible for the contamination and browning of material in the initial stages of P. occidentalis tissue cultures.  相似文献   

Policies Affecting Forestry Entrepreneurship   总被引：1，自引：0，他引：1  

Anssi Niskanen  Anders Lunnan  Ikuo Ota  Keith Blatner  John Herbohn  Lyndall Bull  Ian Ferguson  Gordon M. Hickey 《Small-Scale Forestry》2007,6(3):233-255

Many demand and supply-side policies impede or foster forestry entrepreneurship. A study was conducted to consolidate existing knowledge on policies influencing forestry entrepreneurship in Finland, Norway, Japan, Australia, the Philippines and the USA, and to draw conclusions on these impeding and fostering factors. From the country studies it was difficult to find common structures on policies affecting forestry entrepreneurship. This is understandable because most policies in forestry are aimed at supporting sustainable forest management, wood production and ecological services of the forests rather than entrepreneurship as such. Despite the high variety of policies applied in the study countries, it can be concluded that strict public control on forests’ use and management potentially impedes forestry entrepreneurship. While these policies assist to correct market failure and to promote sustainability of forest management, they may also result into unnecessary and ineffective regulations that limit the opportunities for forestry entrepreneurship. A common feature promoting the demand for forestry entrepreneurship in some of the countries studied is the strong emphasis on forestry cooperatives, which were important institutions to support small-scale forestry entrepreneurship. In many study countries, different ad hoc programs are implemented to find new economic and entrepreneurial opportunities aside from the current use of wood and forests. Subsidies and tax incentives are commonly applied to reduce risks from making forestry investments or otherwise increase the economic return from timber production.  相似文献   

Regional mixed-effects height–diameter models for loblolly pine (<Emphasis Type="Italic">Pinus taeda</Emphasis> L.) plantations     

Guillermo Trincado  Curtis L. VanderSchaaf  Harold E. Burkhart 《European Journal of Forest Research》2007,126(2):253-262

A height–diameter mixed-effects model was developed for loblolly pine (Pinus taeda L.) plantations in the southeastern US. Data were obtained from a region-wide thinning study established by the Loblolly Pine Growth and Yield Research Cooperative at Virginia Tech. The height–diameter model was based on an allometric function, which was linearized to include both fixed- and random-effects parameters. A test of regional-specific fixed-effects parameters indicated that separate equations were needed to estimate total tree heights in the Piedmont and Coastal Plain physiographic regions. The effect of sample size on the ability to estimate random-effects parameters in a new plot was analyzed. For both regions, an increase in the number of sample trees decreased the bias when the equation was applied to independent data. This investigation showed that the use of a calibrated response using one sample tree per plot makes the inclusion of additional predictor variables (e.g., stand density) unnecessary. A numerical example demonstrates the methodology used to predict random effects parameters, and thus, to estimate plot specific height–diameter relationships.  相似文献   

First-year growth response of cold-stored,nursery-grown aspen planting stock     

Lee A. Martens  Simon M. Landhäusser  Victor J. Lieffers 《New Forests》2007,33(3):281-295

This research examined the first year growth characteristics of cold stored and transplanted nursery-produced aspen (Populus tremuloides) seedlings (container and bareroot (BR)) and compared it to the growth of seedlings that had not been transplanted (established from germinants in the field) and therefore had an unrestricted root system (UR). Prior to planting, nursery-produced seedlings were placed in cold storage (−3°C) and root growth potential (RGP) and total non-structural carbohydrate (TNC) root reserves were tested at 0, 10, 75 and after 150 (container) and 190 days (BR) of storage. Both container and BR stock had much lower root to shoot ratios (RSRs) and root carbohydrate reserves compared to UR seedlings after 170 days. During storage, root reserves in container stock declined faster than in the BR and UR seedlings. RGP in all nursery stock was the highest after 75 days of storage, while longer storage resulted in shoot dieback and reduced root growth. After the first growing season, UR seedlings were one tenth the size of the nursery stock; however, in the second growing season they had no stem dieback and grew twice the height and stem diameter. The higher RSRs and root reserves in the UR seedlings was likely caused by early bud set in its first year of growth. This suggests that inducing bud set earlier in the growing regime might allow seedlings to increase root mass and carbohydrate reserves.  相似文献   

Radial variation of vessel size and distribution in cork oak wood (<Emphasis Type="Italic">Quercus suber</Emphasis> L.)     

Sofia Leal  Vicelina B. Sousa  Helena Pereira 《Wood Science and Technology》2007,41(4):339-350

Quercus suber L. is an important species producing cork whose wood characteristics have not been investigated a lot. Cork oak wood vessels are a striking feature and the most abundant wood tissue largely influencing density and permeability. Vessel size and distribution were studied in approximately 40 year-old and never debarked cork oaks by continuously measuring along the radial direction in the transverse section of wood discs taken at 1.3 m of height using image analysis techniques. The vessel size increases with age from 7660 ± 2286 to 21136 ± 6119 μm², the conductive area from 5.4 ± 2.2 to 11.6 ± 3.9%, and the vessel density remains approximately constant between 5.2 ± 1.5 and 7.3 ± 3.5 vessels/mm². In comparison with ring-porous and some evergreen oaks, cork oaks show a similar conductive area but smaller vessels. Vessel architecture is known to play an important role on oaks tolerance to hydric stress, and these cork oak trees were growing under very harsh edaphoclimatic conditions, not tolerated by other oaks. The well-developed and deep root system allowing access to constant water supply may contribute to the cork oak’s relatively high conductive area.  相似文献