Wood Microstructure Effects on Chinese White Poplar Dyeing

In order to study the influence of wood microstructure on wood dyeing, eleven parameters of wood microstructure and 5 parameters of wood dyeing effects for 34 pieces of wood boards from 5 trees of Chinese white poplar (Populus tomentosa) were determined and the multiple regression analysis between the factors of wood microstructures and the parameters of wood dyeing effects were made. The regression results show that each variable of wood dyeing effects has higher relationship with wood microstructures, and multiple correlation coefficients between each variable of wood dyeing effects and wood microstructures are 0.483 6~0.799 8. The main factors of wood microstructures influencing wood dyeing of Chinese white poplar are proportion of wood ray, proportion of vessel and proportion of wood fiber according to comparing the standardized regression coefficients of multiple regression equation.     

Use of Near Infrared Spectroscopy to Measure Mechanical Properties of Solid Wood

The visible and near infrared （NIR） （350-2500 nm） spectra and the MOE of 438 small clear wood samples from Chinese fir, eucalyptus and poplar 72 were measured. Using partial least-square （PLS） modeling, the NIR spectra could be used to predict MOE and MOR of the clear-wood samples from Chinese fir and eucalyptus solid wood. NIR spectra could only be used to Predict MOE but not MOR of poplar clear-wood samples. With the exception of MoR of poplar clear-wood samples, the correlations between NIR and the mechanical properties are very strong, and the calibration and test correlation coefficients are both above 0.80.     

Analysis of Original Causes of Reed Fires in Zhalong Nature Wetland Reserve in Heilongjiang Province

Zhalong Nature Reserve is located in the border areaof Qiqihaer City, Fuyu County, Lindian County andTailai County of Heilongjiang Province. The area ofthe reserve is 210 000 ha. The reserve is the firstnature reserve for protecting wetland and crane inChina. There were more than 300 red-crownedcranes here at the very most. Zhalong Nature Reserveis situated at the Songnen Plain, the lower stream ofthe Wuyuer River. It is the biggest nature reserve inChina that takes crane and wetland …     

Early and late root formation in epicotyl cuttings of Pinus sylvestris after auxin treatment

Auxin stimulated rooting of epicotyl cuttings of Pinus sylvestris irrespective of the physiological stage of the plant from which the cuttings were taken. The epicotyl cuttings were divided into two groups, those that differentiated roots early (within 6 weeks after cutting) and those that differentiated roots late (more than 6 weeks after cutting). Auxin treatment significantly stimulated the frequency of early rooting of epicotyl cuttings, whereas it had no effect on the frequency of late rooting of epicotyl cuttings. The number of roots per rooted cutting was significantly higher after auxin treatment both on early and late rooted cuttings. Anatomical studies showed that most of the roots on both early and late rooted cuttings developed from wound tissue. However some types of rooting were found only after auxin treatment of early rooted cuttings, e.g., roots that developed from resin duct wound tissue or from vascular tissue or in the pith.     

Analysis of Sediment Source of Watershed in Western Shanxi of the Loess Plateau

1 INTRODUCTIONThe Loess Plateau is the most drastic soil erosion regionin China, with the most severe water erosion. Thedistribution of types and intensity of erosion not onlyhave regional diversity but also have perpendicularvariation. In the small watershed, there are differencesin erosion characters among its upper, middle and lowerreaches. It is very significant for taking rationalmeasures of soil and water conservation and forpreventing soil and water loss to analyze the relationbe…     

Study on Balance between Supply and Demand for Timber and Timber Products in China

INTRODUCTION Because China is deficient in forest resources, and the forest has the characteristics of low quality, uneven distribution, slow growth and severe situation of ecological environment, the ecology construction has become the first requirement in society and with the implementation of the “Natural Forest Conservation Program”, Chinese forestry is in the historic transition from timber production to ecological construction. Therefore, the timber production in China increases…     

Cytotoxic pentacyclic triterpenes from Combretum nigricans

A new pentacyclic triterpene, 11alpha-acetoxy-20,24-epoxy-25-hydroxy-dammar-3-one (1), has been isolated from the African tree Combretum nigricans, together with the known corresponding diol, 20,24-epoxy-11alpha, 25-dihydroxy-dammar-3-one (2). They are responsible, at least in part, for the cytotoxic activity of the methanolic extract of the plant.     

Determination of inter- and intra-species genetic relationships among six Eucalyptus species based on inter-simple sequence repeats (ISSR)

Eucalyptus is the most economically important hardwood plantation tree cultivated in tropical and subtropical countries. Inter-simple sequence repeat (ISSR) markers were used to evaluate genetic relationships within and between individuals of six Eucalyptus species. A total of 583 loci (265 to 1535 bp) were amplified from 149 individuals belonging to the six Eucalyptus species using seven ISSR primers (two to three nucleotide repeats anchored with one or two nucleotides at the 3' or 5' region). The ISSR fragments indicated significant polymorphism and genetic diversity among the individuals. Cluster analysis and principal component analysis revealed the occurrence of wide genetic diversity among populations of E. tereticornis Sm., E. camaldulensis Dehnh. and E. urophylla S.T. Blake and narrow genetic diversity among populations of E. citriodora Hook. and E. grandis W. Hill ex Maiden. Genetic diversity was high in E. tereticornis Sm. (47.27%) and low in E. citriodora (18.64%). Maximum Nei's genetic identity (0.897) was observed between E. camaldulensis and E. tereticornis species, whereas maximum genetic diversity (0.286) was found between individuals of E. citriodora and E. grandis.     

Strategic Trend of Chinese Urban Forestry Development

1 STRATEGY BACKGROUND1.1 Quickening of Urbanization ProcessSince the reform and opening-up in China in 1978,economic community developed rapidly. By the endof 2003, GDP has exceeded $1 000 billion. With therapid development of Chinese economy, residentialmode focusing on rural population is now changing,urbanization process is quickening, traditional cityscale is expanding into metropolis (Tianjin, Xi’an,Chengdu, Chongqing, etc.) or super cities (Beijing,Shanghai, Guangzhou, etc.…     

Changes in fruit sugar concentrations in response to assimilate supply,metabolism and dilution: a modeling approach applied to peach fruit (Prunus persica)

The influence of assimilate supply, metabolism and dilution on sugar concentrations in the mesocarp of peach (Prunus persica (L.) Batsch) fruit during the main stage of fruit enlargement was analyzed with the SUGAR model of Génard and Souty (1996). The model predicts the partitioning of carbon into sucrose, sorbitol, glucose and fructose in the mesocarp of peach fruit. Based on measured data and the model, we determined values for the relative rates of sugar transformation. These rates were constant, varied with time or varied with relative fruit growth rate, depending on the type of sugar. Equations were derived to describe these rates and incorporated into the SUGAR model. The model simulated the effects of changing assimilate supply and fruit volume on sugar concentrations. The set of equations for the SUGAR model was rewritten to include the three components influencing sugar concentrations: assimilate supply, metabolism and dilution. The sugar types differed in sensitivity to these components. Sucrose was highly sensitive to changes in assimilate supply and to the dilution effect; it was not subject to intense metabolic transformation. Sorbitol was the most important carbohydrate in fruit metabolism, which explains why the sorbitol concentration was always low despite the strong positive effect of assimilate supply. The reducing sugars constituted a transitory storage pool and their concentrations were closely related to metabolism.