2025-04-08 2011, Volume 22 Issue 1

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  • Tohru Nakajima , Hidesato Kanomata , Mitsuo Matsumoto , Satoshi Tatsuhara , Norihiko Shiraishi

    This study uses simulations to investigate the effects of implementing two different Japanese forestry subsidy systems on timber production and carbon stock, and examines the consequences for harvesting strategies. An existing Local Yield Table Construction System (LYCS), a wood conversion algorithm, and a harvesting cost model were used in the simulations to test the applicability of different subsidies to the thinning of stands. Using forest inventory data collected by local government staff, simulation output was used to calculate forestry profits, carbon stocks, subsidies, the amount of labor required, and the cost effectiveness of investing in subsidies. By comparing the output of simulations based on two scenarios, we found that both the clear-cutting area and the amount of harvested timber were larger under Scenario 2, in which the rules governing subsidy allocations are more relaxed, than under Scenario 1, in which the rules are more restrictive. Because the harvested timber under Scenario 1 was mainly produced by clear-cutting, the forestry profits and the subsidy predicted in the early period of the simulation, were larger under Scenario 1 than under Scenario 2. In contrast, the carbon stock was larger under Scenario 2 than under Scenario 1. The simulation model is likely to be useful for improving Plan-Do-Check-Act cycles implemented in Japanese forest management systems.

  • Toshiaki Owari , Naoto Kamata , Takeshi Tange , Mikio Kaji , Akio Shimomura

    Hurricanes cause abrupt carbon reduction in forests, but silviculture treatment can be an effective means of quickly regenerating and restoring hurricane-damaged sites. This study assessed how silviculture treatments affect carbon balance after hurricane damage in central Hokkaido, Japan. We examined carbon storage in trees and underground vegetation as well as carbon emissions from silviculture operations in 25-year-old stands, where scarification and plantation occurred just after hurricane damage. The amount of carbon stored varied according to silviculture treatment. Among three scarification treatments, a scarified depth of 0 cm (understory vegetation removal) led to the largest amount of carbon stored (64.7 t·ha−1 C). Among four plantation treatments, the largest amount of carbon was stored in a Larix hybrid (L. gmelinii var. japonica × L. kaempferi) plantation (80.3 t·ha−1 C). The plantation of Abies sachalinensis was not successful at accumulating carbon (40.5·ha−1 C). The amount of carbon emitted from silviculture operations was 0.05–0.14 t·ha−1 C, and it marginally affected the net carbon balance of the silviculture project. Results indicate that silviculture treatments should be performed in an appropriate way to effectively recover the ability of carbon sequestration in hurricane-damaged forests.

  • V. Sivakuma , B. Gurudevsingh , R. Anandalakshmi , R. R. Warrier , S. Sekaran , Mulualem Tigabu , P. C. Odén

    Improvement in seed and seedling quality of Acacia auriculiformis after culling phenotypically inferior trees was studied in a 6-year old seed production area (SPA). A 5-ha plantation was identified, of which 2.3 ha was converted into SPA. The initial stocking, 1 612 trees·ha−1, was thinned down to 982 trees·ha−1 based on growth characteristics. The following fruiting season, seeds were collected from 10 randomly selected trees in culled and non-culled stands, and seed physical characters, germination and seedling traits were assessed. Seed weight, seed thickness and percentage germination increased by 32.1%, 4.43% and 22.37%, respectively in the culled stand compared to the non-culled stand. Culling also increased the speed of germination, seedling dry weight and seedling vigor index. Heritability values were high for seed weight (0.974) and seed thickness (0.948) while medium values were observed for percentage germination (0.577) and total dry weight (0.534). Predicted genetic gain was 11.13% and 11.22% for seed weight and percentage germination, respectively. The actual gain was 32.1, 51.9 and 22.9% for seed weight, percentage germination and total dry matter, respectively. In conclusion, SPAs established by culling inferior trees could serve as sources of good quality seeds for reforestation programs until genetically improved seeds are made available.

  • Ling Yang , Hai-long Shen

    A study was conducted to determine the effects of electrostatic field (ESF) treatment on seed germination and seedling growth of Sorbus pohuashanesis. The experiments were arranged by uniform design computed by the Data Processing System (DPS), including three levels of seeds soaking time, four levels of ESF intensity and four levels of ESF treatment time, with 12 treatments. Ten seeds were used in each treatment with three replicates. Seed vigor, seed germinating ability, emergence rate of seedling, survival rate of seedling, and seedling height and diameter, as well as the change in activities of superoxide dismutase (SOD), soluble protein contents, total chlorophyll contents, soluble total sugar contents in leaves of S. pohuashanensis seedlings were measured after ESF treatments. The experiment results show that ESF treatment could improve the water absorption ability of dry seeds of S. pohuashanensis, resulting in fast germination at room temperature under light conditions. Combined treatment of ESF with cold stratification could increase seed germination percentage significantly (to 42.20%), promote seedling height growth, affect leaf SOD activity, and could raise contents of total chlorophyll, soluble protein, and total soluble sugar in leaves. Seed soaking time had a significant effect on seed relative electroconductivity, seed germination under light, SOD activity, soluble protein content and total soluble sugar content of seedling leaves. ESF intensity exerted a moderate effect on these indexes. ESF treatment time only had significant effect on total chlorophyll contents, no evident effect on other indexes.

  • Salman Zare , Ali Tavili , Mohammad Javad Darini

    For improving seed germination of Prosopis koelziana and Prosopis juliflora, different treatments of seeds were conducted, including scarification with sulfuric acid 98% for 10 and 15 min, sandy paper, hot water for 5 and 10 min, potasium nitrate 0.1%, gibberellic acid at 250 mg·L−1 and 500 mg·L−1 and combinational treatment of scarification with gibberellic acid of 250 mg·L−1 and 500 mg·L−1. The results show that scarifications with sandy paper and sulfuric acids 98% were the most effective treatments on breaking seed dormancy and seed germination induction. Scarification with sulfuric acid 98% for 15 min was the best treatment. According to the positive effect of scarification and lack of reaction of seeds against KNO3 and gibberellic acid, the kind of seed dormancy was determined as exogenous.

  • Parveen , A. Kumar , H. S. Ginwal

    A field trial of 20 seed sources of Asparagus racemosus was conducted at the Forest Research Institute, Dehradun, Uttarakhand, India to evaluate their performance of different economic traits. Genotypic variance, phenotypic variance, genotypic coefficient of variance (GCV) and phenotypic coefficient of variance (PCV) for number of shoots, shoot height, shoot weight, number of roots, root length, root diameter and root weight were calculated. Maximum genotypic and phenotypic variance was observed in shoot height among the shoot — related traits and root length among the root — related traits. For the shoot height, genotypic variance, phenotypic variance, genotypic coefficient of variance, phenotypic coefficient of variance were 231.80, 3924.80, 61.26 and 1037.32, respectively, where those of the root length were 9.55, 16.80, 23.46 and 41.27, respectively. The maximum genetic advance and genetic gain were obtained for shoot height among the shoot-related traits and root length among the root-related traits. Index values were developed for all the seed sources based on the four most important traits, and Panthnagar (Uttrakhand), Jodhpur (Rajasthan), Dehradun (Uttarakhand), Chandigarh (Punjab), Jammu (Jammu and Kashmir) and Solan (Himachal Pradesh), were promising seed sources for root production.

  • Arun Jyoti Nath , Ashesh Kumar Das

    Schizostachyum dullooa (Gamble) Majumder ‘dolu bamboo’ is a thin walled sympodial moderate sized to large tufted bamboo, dominant in the successional fallows of northeast India. The impact of resource management on productivity and sustainability of the species was evaluated by investigating the population status and regeneration in Cachar tropical semi evergreen forest under private property resource management (PPRM) and common property resource management (CPRM) regimes. Population status revealed current-year, one-year, two-year and three-year-old culms contribute 54%, 24%, 16% and 6% of the total culms per clump, respectively, under PPRM. Three-year-old culms were absent in CPRM and population status was thus represented by current year (83%), one-year (16%) and two-year (1%) old culms. Net change, rate of change and % gain in population for different age classes showed the prevalence of management practices under CPRM was unscientific. Efficiency of new culm production per clump used as an index of regeneration was 69.7% in PPRM and 59.88% in CPRM. New culms produced under CPRM were small and thin. We conclude that CPRM is inappropriate for a long term economic and ecological sustainability of the species and alternative management protocols are needed for conservation of the species.

  • Shahnaz Perveen , Ankita Varshney , Mohammad Anis , Ibrahim M. Aref

    A highly reproducible and efficient in vitro shoot regeneration system was developed in a potential medicinal plant, Albizia lebbeck using root explants. Root explants from 15 day-old-aseptic seedlings were cultured on Murashige and Skoog (MS) medium supplemented with different concentrations (0.5, 2.5, 5.0, 7.5 and 10.0 μM) of 6-Benzyladenine (BA), Kinetin (Kn), 2-Isopentenyl adenine (2-iP) singly as well as in combination with α-Naphthalene acetic acid (NAA) (0.1, 0.5, 1.0, 1.5 and 2.0 μM). The highest rate of shoot multiplication (16.0 ± 1.87 for the average shoot number and 5.16 ± 0.38 cm for shoot length) was achieved on MS medium supplemented with 7.5 μM BA and 0.5 μM NAA. The effects of medium type, medium strength, pH and subculture on shoot induction and proliferation were also tested. An average of 21.6±2.87 shoots per explants could be obtained following this protocol. Rooting was achieved on microshoots using half strength MS medium with 2.0 μM Indole-3-butyric acid (IBA) after four weeks of culture. The in vitro raised healthy plantlets were successfully established in earthen pots containing garden soil and grown in greenhouse with >80% survival rate.

  • Bhupendra Singh , Rajendra Yadav , B. P. Bhatt

    Dalbergia sissoo Roxb. is one of the promising multipurpose tree species of South Asia. Most of the plantations of D. sissoo from seeds are facing severe threats due to the die-back disease, which ultimately causes death of this potential tree-species within a few months. Vegetative propagation could avoid the die-back disease. Thirty mother trees of different age-groups of D. sissoo were selected for evaluating the rooting behaviour of branch cuttings from D. sissoo as influenced by auxins (IAA or IBA at 100, 200, 500 mg·L−1), ages of mother trees (10, 4 and 2 years old) and different environment conditions, i.e., different mediums (soil and sand) or light conditions (in shade and open condition). The results show that application of IAA and IBA induced more numbers of cuttings (collected from 10-year-old mother trees) to root compared to control. Branch cuttings of D. sissoo collected from 10-year-old mother trees and planted in soil bed in open conditions had 100.0% of cuttings to root in IAA (100 mg·L−1) and IBA (200 mg·L−1) treatments. Both rooting medium (Soil and sand) influenced significantly (p<0.05) on rooting response of branch cuttings. Soil medium was found to achieve maximum no. of branch cuttings to root, compared to sand medium.

  • Yong-qing Yan , Dai-di Che , Xi-chan Shi , Xing-liang Liu

    Under artificially-simulated complex salt-alkali stress, the levels of active oxygen metabolism in roots were studied using three-year-old cutting seedlings of Spiraea × bumalda ‘Gold Mound’ and Spiraea × bumalda ‘Gold Flame’. The present study aimed at exploring the antioxidant capacity in roots of spiraeas and revealing their adaptability to salt-alkali stress. Results indicate that the oxygen free radicals contents, electrolyte leakage rates and MDA contents in roots of Spiraea × bumalda ‘Gold Mound’ and Spiraea × bumalda ‘Gold Flame’ show an increasing tendency with the increases of the salinity and pH value, whereas the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) all increased firstly and then decreased. With the increase in intensity of salt-alkali stress, the CAT activity in roots of Spiraea × bumalda ‘Gold Flame’ is higher and the increasing extents in the oxygen free radicals contents, electrolyte leakage rates as well as MDA contents are lower compared with Spiraea × bumalda ‘Gold Mound’, indicating that Spiraea × bumalda ‘Gold Flame’ has a stronger antioxidant capacity.

  • Rong-xin Deng , Ying Li , Shu-wen Zhang , Wen-juan Wang , Xiao-liang Shi

    At present, the most researches on the protected effect of shelterbelt are on the basis of the two scales of forest belts and networks. However, with the further research on the global environmental change, more attention was paid to the regional climate effect of shelterbelt. In present study, we analyzed the temperature effect of the shelterbelt at regional scale by using the land surface temperature (LST) data from the moderate resolution imaging spectroradiometer (MODIS) at Yushu, Nong’an, Dehui, and Fuyu in Jilin Province of China from March to October in 2008. Results show that the shelterbelt can increase the soil temperature of the protected farmland as compared with no shelterbelt zone, with the increment of 0.57°C per day in fine shelterbelt and 0.38°C per day in the normal shelterbelt. Moreover, the correlation analysis of the air temperature, precipitation and the soil type and the shelterbelt effect shows that the air temperature and precipitation are negatively correlated with the shelterbelt effects, that is, the more the temperature and precipitation are, the less the effect produced. While the impact of the soil types on the shelterbelt’s effect is not very obvious as a whole. This paper draws significance in terms of analyzing the effects of the shelterbelt on the soil temperature at regional scale utilizing the remotely sensed data and GIS technique.

  • Qiong Zhao , Xing-yu Liu , De-hui Zeng

    Biomass and nutrient (N, P, K, Ca, Mg) stock in various aboveground tree components (stemwood, stembark, branches and leaves) were quantified in an age sequence of pure Larix olgensis plantations (20, 35, 53 and 69 years old) in Northeast China. The results show that the aboveground biomass allocation in various tree components was in the order of stemwood (62%–83%), branches (9%–21%), stembark (7%–11%) and leaves (1%–6%) for all stands. The proportion of stemwood biomass to total aboveground biomass increased whereas that of other tree components decreased consistently with stand age from 20 to 53 years old, but kept relatively constant with stand age from 53 and 69 years old. The nutrient allocation in various tree components generally followed the same pattern as the biomass allocation (i.e. stemwood > branches > stembark > leaves). The proportion of nutrient stock in leaves to total aboveground nutrient stock decreased consistently with increasing stand age, while that in stemwood increased with stand age from 20 to 53 years old but then decreased from 53 to 69 years old. The rate of nutrient removal for stands was estimated at different stand ages under different logging schemes, showing that the rate of nutrient removal would be unchanged when the rotation length was shortened to 20 years by the harvest of stem only, but greatly increased by the harvest of total aboveground biomass. The rate of nutrient removal would be a considerable reduction for all elements by debarking, especially for Ca.

  • K. S. Sangha

    Populus suffers from multiple insect damage throughout its distributional range in northwestern India. The evaluation of various management tools was done based on the hypothesis that manipulation of insect habitat can provide tangible results. Manipulation of cultural practices, ploughing of field during December, and growing of crops (wheat, Trifolium alexandrinum and others) results in lower adult emergence, reduced leaf infestation, number of larvae and pupae per meter branch length of poplar leaf defoliators (PLD). Fallow plantations were more prone to attack of PLD than intercropped plantations. Higher incidence of Clostera restitura was recorded in southwestern dry zones due to unsuitability of the site, poor quality of irrigation water and dry weather conditions. Complete stripping of Populus trees does not occur in low temperature & high humidity, submountaneous zones of Punjab. Chemical control studies were conducted in laboratory & field conditions, and among the five insecticides tested, Profenophos 50 EC, Quinalphos 25 EC and Carbaryl 50 WP @ 0.05 and 0.1 percent concentration gave consistently high mortality of PLD larvae up to 21 days after spraying. Use of insecticides prior to peak activity periods & during evening hours enhances the efficiency of management options.

  • K. S. Sangha

    Poplar leaf defoliator, Clostera fulgurita (Walker) larvae were reared on three Populus deltoides clones (PL1, PL5 and PL7) in the laboratory. The nutritional indices were computed for working out the relationship between food consumption and growth rate of 3rd, 4th and 5th instar larvae on three clones. The result showed that the consumption index (CI), approximate digestibility (AD), growth rate (GR), relative growth rate (RGR) and efficiency of conversion of ingested food (ECI) decreased with the increase in the age of the larvae. Efficiency of conversion of digested food (ECD) increased with increase in age of the larvae. GR and RGR varied significantly, indicating that larval development was enhanced on PL1 as compared to PL5 & PL7. The values of AD, ECI and ECD were not affected by the different clones. Feeding and growth indices could be useful to define a defoliation prediction model.

  • Shyamal Karmakar , S. M. Sirajul Haque , M. Mozaffar Hossain , M. Shafiq

    A study was conducted in Kaptai reservoir, one of the largest man-made freshwater lakes of South-east Asia, to determine present status of water quality and its suitability for fishing and other uses. Water samplings were from middle part of the reservoir at 0.2 and 0.8 fractional depths at five different locations from upstream to downstream viz. Burburichara, Maichchari, Subolong, Basanthakum, and Rangamati. Water analyses show that concentrations of NO3-N, K+ and total P, and suspended solid at all the sampling stations were beyond the recommended values for fish culture. Concentrations of Na+, Ca2+, Mg2+, SO4 2−, Cl, total dissolved solid (TDS), dissolved oxygen (DO) and chemical oxygen demand (COD) were within the standards for aquaculture. Concentrations of NO3-N, SO4 2−, K+ and total P showed no definite trend with depths, locations as well as rainy and dry seasons. Water pH, conductivity, Na+ and HCO3 contents were lower in rainy season, and DO and COD higher at almost all the locations in both the depths, compared with dry season. Total solids and concentrations of TDS, DO, COD, Ca2+, Mg2+ and Na+ were higher in upstream and decreased gradually towards downstream in the reservoir. Concentrations of DO and Ca2+ and pH were higher and Mg2+ less at 0.2-fractional depth than those at 0.8-fractional depth at almost all the locations. The reservoir is in mesotrophic condition containing high concentration of NO3-N and total P, in alarming status with the presence of excessive suspended solids from urban pollution around the town. It is necessary to adopt measures for protecting water quality in the reservoir due to such deteriorations.

  • Hai-long Zhang , Gao-huan Liu , Xian-feng Feng

    Terrestrial carbon cycle and the global atmospheric CO2 budget are important foci in global climate change research. Simulating net primary productivity (NPP) of terrestrial ecosystems is important for carbon cycle research. In this study, a plant-atmosphere-soil continuum nitrogen (N) cycling model was developed and incorporated into the Boreal Ecosystem Productivity Simulator (BEPS) model. With the established database (leaf area index, land cover, daily meteorology data, vegetation and soil) at a 1 km resolution, daily maps of NPP for Lantsang valley in 2007 were produced, and the spatial-temporal patterns of NPP and mechanisms of its responses to soil N level were further explored. The total NPP and mean NPP of Lantsang valley in 2007 were 66.5 Tg C and 416 g·m−2·a−1 C, respectively. In addition, statistical analysis of NPP of different land cover types was conducted and investigated. Compared with BEPS model (without considering nitrogen effect), it was inferred that the plant carbon fixing for the upstream of Lantsang valley was also limited by soil available nitrogen besides temperature and precipitation. However, nitrogen has no evident limitation to NPP accumulation of broadleaf forest, which mainly distributed in the downstream of Lantsang valley.

  • Nilanchal Patel , Brijesh Kaushal

    The present investigation was performed to determine if the features selected through Optimum Index Factor (OIF) could provide improved classification accuracy of the various categories on the satellite images of the individual years as well as stacked images of two different years as compared to all the features considered together. Further, in order to determine if there occurs increase in the classification accuracy of the different categories with corresponding increase in the OIF values of the features extracted from both the individual years’ and stacked images, we performed linear regression between the producer’s accuracy (PA) of the various categories with the OIF values of the different combinations of the features. The investigations demonstrated that there occurs significant improvement in the PA of two impervious categories viz. moderate built-up and low density built-up determined from the classification of the bands and principal components associated with the highest OIF value as compared to all the bands and principal components for both the individual years’ and stacked images respectively. Regression analyses exhibited positive trends between the regression coefficients and OIF values for the various categories determined for the individual years’ and stacked images respectively signifying the prevalence of direct relationship between the increase in the information content with corresponding increase in the OIF values. The research proved that features extracted through OIF from both the individual years’ and stacked images are capable of providing significantly improved PA as compared to all the features pooled together.

  • Jiang-hua Shen , Zhi-ming Liu , Jing Li , Jing Niu

    A study was conducted to test wettability changes of the wheat straw treated with different methods for the preparation of wheat straw particle board. The wheat straws were separately sprayed with two chemicals (0.6% NaOH, 0.3% H2O2) and three enzymes (lipase, xylanase, cellulase). The contact angle between water and the surface of wheat straw was measured and the spreading-penetration parameters (K-values) were also calculated with wetting model. The surfaces of treated wheat straw and control sample were scanned by means of Micro-FTIR, and their peaks arrangements were analyzed. The surface morphologies of treated wheat straw and control sample were also observed by SEM. Chemical etching was found on the exterior surfaces of the straws treated separately with 0.6% NaOH and 0.3% H2O2; furthermore, the spreading-penetration parameters (K-values) of the distilled water on the exterior surfaces of the treated wheat straw along the grain were higher than that of control. The wettability of exterior surfaces of the wheat straws treated separately with lipase, xylanase and cellulose were improved after treating for seven days, and among the three enzymes treatments, the lipase treatment showed best result. The lipase treatment and NaOH treatment were determined as better methods for improving the wettability of wheat straw surfaces. However, in the economic aspect, NaOH treatment was more practical and easier in the pretreatment for the manufacture of straw particle board.

  • Ajaye Babatunde

    Cement-bonded particleboards of 6 mm in thickness were manufactured using maize stalk (Zea mays) particles of uniform sizes at three levels of board density and additive concentrations respectively. The bending strength and dimensional properties were assessed. Increase in board density and additive concentration caused increase in Modulus of rupture (MOR), Modulus of elasticity (MOE), and decrease in Thickness swelling (TS) and Water absorption (WA). The MOR, MOE and TS of the boards were significantly affected by board density except for WA, but additive concentration affected all the boards’ properties examined at p ≥ 0.05. Strong and dimensional stable cement-bonded boards could be manufactured from maize stalk particles with Portland cement as the binder after hot water treatment. Although the dimensional stability and mechanical strength properties of the boards were affected by the board density and additive concentration, the study revealed that cement-bonded particleboards could be manufactured from maize stalk (Zea mays) particles. However, the increase in board density and additive concentration could cause the increase in MOR and MOE, and cause the decrease in TS and WA of boards.

  • Idris Musa Adam , Kamal E. M. Fadl

    A study was conducted in South Kordofan, Sudan to determine the effect of tapping, tapping tools and date of tapping on the gum yield of Acacia polyacantha. A two-factor experiment was conducted for two seasons in 2008–2009. One location was used for two seasons and two locations for one season. The first factor (4 levels) was the tools of tapping: Makmak, Farrar, and Sonki, and the control which was not tapped. The second factor (2 levels) was the date of tapping that comprises mid October and mid November. These treatments were arranged in Randomaized Complete Block Design and replicated three times. Gum yield (g/tree and g/ picking) was recorded for five pickings. Economic analysis was done using the partial budget technique. The results showed highly significant (p < 0.01) differences on gum yield (g/picking and g/tree). The results indicated that the process of tapping increases gum production by 88.4% and 79.8% compared with un-tapped trees, respectively. The date of tapping has no significant effect on gum yield (g/tree and g/picking) of A. polyacantha. Tapping of the tree with Makmak in mid-November was found to be economically beneficial compared to using the other tools and the control. These results could identify a new source of income for the poor farmers in South Kordofan mainly because of the wild occurrence of Kakamut as a potential gum producing tree species grown naturally in the area.

  • Zong-yue Liu , Fang-yong Ning , Hong-yan Yang , Lai Wei , Xiu-juan Bai

    Self-biting disease occurred in most farmed fur animals in the world. The mechanism and rapid detection method of this disease has not been reported. We applied bulked sergeant analysis (BSA) in combination with RAPD method to analyze a molecular genetic marker linked with self-biting trait in mink group. The molecular marker was converted into sequence-characterized amplified regions (SCAR) marker for rapid detection of this disease. A single RAPD marker A8 amplified a specific band of 263bp in self-biting minks, which was designated as SRA8-250, and non-specific band of 315bp in both self-biting and healthy minks. The sequences of the bands exhibited 75% and 88% similarity to Canis familiarizes major histocompatibility complex (MHC) class II region and Macaca mulatta MHC class I region, respectively. A SCAR marker SCAR-A8 was designed for the specific fragment SRA8-250 and validated in 30 self-biting minks and 30 healthy minks. Positive amplification of SCAR-A8 was detected in 24 self-biting minks and 12 healthy minks. χ2 test showed significant difference (p<0.01) in the detection rate between the two groups. This indicated that SRA8-250 can be used as a positive marker to detect self-biting disease in minks. Furthermore, the finding that self-biting disease links with MHC genes has significant implications for the mechanism of the disease.

  • Hai-tao Li , Chen-jie Gu , Tao Liang , Jian-ye Xu , Ranjeet John

    Ecosystem health has attracted considerable attention from different disciplines in recent years. However, it still remains a disputed issue whether to focus on its general concept or on operational practice. As a result, these disputations have caused confusion and limited further research in the field of ecosystem health. In this paper, we attempt to introduce a new perspective to the concept of ecosystem health. With the aid of modern statistical methodology, such as factor analysis and normal distribution theory, we provide a conceptual approach to the quantitative assessment of ecosystem health and our method could be applied to various categories of ecosystems.

  • Mo-long Sun , Tian-miao Wang

    The extract from leaves of Rhododendron dauricum L. was extracted with 95% alcohol by common method for studying its insecticidal activities. The chemical components of the alcohol extract and relative contents were analyzed by GC-MS. The insecticidal activities of the alcohol extract were tested on the 2nd–3rd instar larvae of Lymantria dispar L. for five days. Five concentrations of the extract samples were designed as 50, 10, 5, 1, and 0.5 g·L−1. The results show that the alcohol extracts from leaves of R. dauricum exhibited insecticidal activities against larvae of L. dispar. The corrected mortality of larvae of L. dispar for was over 50% for both contact toxicity and stomach toxicity at the extract concentration of ≥ 5 g·L−1 after five days of application. The insecticidal activity in contact toxicity is more effect than stomach toxicity for the alcohol extract. Twenty compounds, with total GC relative contents of 93.81% in the alcohol extract from leaves of R. dauricum were identified. The main chemical components in the extract are: (1) 4,5-Dihydro-5-oxo-3-(p-tolyl) isoxazole, with a relative content of 40.03%; (2) 1,3-Benzenediol, 5-methyl-2-(3,7,11-trimethyl-2,6,10-dodecatrienyl)-, (E,E)-, the relative content 18.27%; (3) 3,6-Diphenyl-1,2,3,4,5,6,7,8-octahydro-1,8-acridinedione, the relative content 3.89%; (4) 6H-[1,2,4]Triazolo[1,5-a]indole, 4a,5,7,8,8a,9-hexahydro-9-methylene-, the relative content 2.99%; (5) 7-Amino-4-methyl-1,8-naphthyridin-2-ol, the relative content 2.64%; (6) 4-Methyl-2,6-dihydroxyquinoline, the relative content 2.63%; (7) 2,4,6-Triaminoquinazoline, the relative content 2.27%; (8) 2(1H)-Quinolinone, 4-hydroxy-1-methyl-, the relative content 2.02%.

  • Xiao-nan Yu , Peng-peng Guo , Guang-pei Lu , Qi-xiang Zhang

    The herbaceous peony is one of the cut flowers that has become increasingly popular in the international market in recent years. In the study, 11 cultivars of herbaceous peonies suitable for cutting flowers were selected; different harvesting stages (three or four stages) were identified according to bud development observation (bud firmness, bud diameter, sepal angle, petal angle, and color showing). Moreover, flower development and vase life were also recorded in the experiment of vase. Bud development observation shows that there are great differences in optimum harvesting stage between the cultivars, especially between the hybrid peony group and lactiflora group. This implies that bud diameter could not be the only indicator for optimum harvesting stage. Bud description, including sepal opening angle, sepal color, petal color showing, and degree of firmness, is necessary for the determination of the harvesting stage. Among the 11 cultivars, ‘Pink Hawaiian Coral’, ‘Red Charm’, ‘Edulis Superba’, ‘Red Magic’, and ‘Sarah Bernhardt’ should be harvested at stage 1. ‘Duchesse de Nemours’, ‘Taff’, ‘Sorbet’ and ‘Monsieur Jules Elie’ should be harvested at stage 2. ‘Kansas’ should be at stage 3 and ‘Karl Rosenfield’ at stage 4. The determination of optimum harvesting stage for each cultivar is an important element in cut flower production.

  • Qiang Liu , Jun Wang

    The height growth of Korean pine plantation was investigated for different ages of saplings in Benxi city of the eastern Liaoning, China. The sapling and seedling age were determined by branch annuals. Results show that the mean height of third- to eight-year Korean pines ranges from 13.31 cm to 111.73 cm and only 19.4% of the saplings reached the height above 130 cm. The height (Y) of eight-year-old Korean pine increases linearly with the increment of ground stem (x) (Y=3.1x+35.15). The relation between height and age can be described by an exponential equation. The second year after planting of the Korean pine is considered as the key period of Korean pine growth really adapting to the local environment; plantation management should be strengthened in this year. The Korean pine seedlings need two years to adapt to the local environment, thus early care and management should be taken in the second year.

  • Cheng-shui Xu , Hong-fei Zou , Hong-hai Zhang