Lu Zhao-hua

Review on studies ofEupatorium adenophoruman important invasive species in China

Eupatorium adenophorum Spreng. was introduced in Yunnan Province of China around 1940. Since then it has been spreading rapidly, particularly in the southern and southwestern parts of China and caused serious economic loss. The biological research and integrated control onE. adenophorum were carried out from 1980’s in Yunnan Province. Together with other 15 invasive external species, the weed has been listed in the White Paper by The State Environmental Protection Administration of China. This paper briefly reviews the studies on natural distribution, biological character, ecological character, chemical component, hazard, potential application and the control ofE. adenophorum. The research direction for this invasive external species in future was also discussed.

Natural vegetation recovery on waste dump in opencast coalmine area

The changes of vegetation compositions, plant species diversity, species important value and succession of plant community were studied on waste dumps in Haizhou opencast coalmine which is located in the west of Liaoning Province, China (41°41′–42°56′ N, 121°1′–122°56′E). Four kinds of terraces with different ages (5, 10, 20 and 40 years) were selected for investigation of plants. Total of 63 species of natural colonized plants were recorded on the waste dump and they belong to 23 families. The main families were Composiatae (15 species), Fabaceae (11 species) and Leguminosae (8 species), which accounted for 54.0% of total species and play an important role in natural vegetation recovery in waste dump area. The dominant species on 5-, 10-, 20-, 40-year-old terraces wereTribulus terrestris+Echinochloa hispidula+Salsola collina, Echinochloa hispidula+Artemisia sieversiana+Artemisia scoparia, Echinochloa hispidula+Clinelymus dahuricus+Artemisia scoparia+Artemisia sieversiana+Melilotus officinalis, Clinelymus dahuricus+Phragmites communis+ Echinochloa hispidula+Setaria viridis, respectively. According to the important value of species calculated. It is determined thatTribulus terrestris can act as pioneer species on waste dump andClinelymus dahuricus, Phragmites communis andEchinochloah hispidula are important dominant species in vegetation restoration in Haizhou opencast coalmine. The study results can provide scientific basis for selecting and disposing appropriately plant species and rehabilitating vegetation on waste dumps of coalmine.

Response of tree-ring width to rainfall gradient along the Tianshan Mountains of northwestern China

By comparing the long-term tree-ring growths at various geographic scales, we can make clear the effects of environmental variations on tree growth, and get an understanding of the responses of forest ecosystems to the possible changes in global and regional climate. Radial tree-ring growth of Picea schrenkiana and its relationship to air temperature and precipitation were investigated across longitude transects on the north slopes of the Tianshan Mountains in northwestern China. Tree-ring samples were collected and residual chronologies were developed for three different regions along a gradient of decreasing precipitation from west to east. Response-function analysis was conducted to quantify the relationships between tree-ring chronologies and climate variables, such as monthly mean temperature and monthly precipitation from 1961 to 1998, using the PRECON software program. The statistical characteristics of the chronologies showed that the three chronologies constructed in this study contained significant environmental signals and were well suitable to reveal the impacts of climatic change on tree growth and forest productivity. Annual ring-width variations were similar among the three sites, but the variability was greatest in the east. This research showed that the growth trends of Picea schrenkiana in the Tianshan Mountains have not followed a uniform pattern. Response-function analysis indicated that there were significant correlations between tree growth and climatic factors in all the three regions, among which precipitation was the principal. With decreasing precipitation, the response of tree-ring widths to increasing temperature changed from a positive to a negative correlation. As for precipitation, the positive relationship to tree-ring width always dominates. It could be expected that with increased temperature and decreased precipitation, the importance of precipitation to three growth would increase, and the response of tree growth to environmental changes would also increase. This study emphasizes the importance of regional-scale investigations into the biosphere-climate interactions. The results of this research indicated a substantial increment of tree-ring radial growth as a result of warmer and wetter climate in the eastern regions. However, climate change will have less effect on forest growth and primary production in the western regions.

Current situation of Chinese forestry tactics and strategy of sustainable development

Based on the analysis of the current situation of Chinese forestry and a series of ecological, environmental, economic, and social problems, this paper emphasized on the importance of forests in social and economic development in China The author pointed out that sustainable development, particularly the sustainable development of forestry, is the inevitable choice to solve the problems of ecological environment and social economics. The objectives, criteria, and strategies of sustaining forestry were also demonstrated and expounded, from the viewpoints of ecology, economics, and sociology.

Critical responses of photosynthetic efficiency in Campsis radicans (L.) Seem to soil water and light intensities

Campsis radicans (L.) Seem is one of the main forestation tree species in semi-arid loess hilly region. Using the CIRAS-2 portable photosynthesis system, the light-response of the photosynthetic efficiency parameters of three-year-old C .radicans leaves, such as net photosynthetic rate (P N ), transpiration rate (Tr), water use efficiency (WUE), and light use efficiency (LUE), were studied under different soil water conditions in order to explore the effects of soil water stress on photosynthesis and the suitable soil water content for water-saving irrigation of this liana. Soil water and light intensity needed by the growth and development of C .radicans were analyzed. The results show that P N , Tr, WUE, and LUE of the leaves had threshold value to soil water and photosynthetically-active radiation (PAR). The nonrectangular hyperbola model was used to simulate light-response curve and the convexity was about 1. With the increase of soil relative water content of field capacity (Wr, ranged from 20.1% to 71.1%), the light compensation point declined while light saturation point, the maximum P N and apparent quantum yield increased. When Wr was about 71.7%, the light compensation point was at the minimum (21.61μmol/m 2 /s) and the light saturation point was at the maximum (1400 μmol/m 2 /s). In order to maintain the normal plant growth and have higher P N , LUE, and WUE synchronously, the range of Wr was from 49.5 to 71.1%. The optimum Wr was 71.1%, and the minimum Wr was 28.2% for the normal growth of C .radicans . The high P N and WUE were recorded when PAR ranged from 800 to 1600 μmol/m 2 /s and the light saturation points ranged from 800 to 1400 μmol/m 2 /s. The peak value of LUE was found when PAR ranged from 100 to 300 μmol/m 2 /s, indicating that the C. radicans had high adaptability to light conditions. Key words : Campsis radicans, soil water content, photosynthetically-active radiation, photosynthetic efficiency, water use efficiency.

Ecological risk assessment of open coal mine area

The coal mine areas in China have the serious conflicts between resources exploitation and ecology safety, therefore the coal mine ecological risk assessment is an important problem which relates to the sustainability of coal mines to regions and the whole country. In this study, open coal mine area serves as researching object, heavy metals, soil erosion and coast are screened out as risk resources, soil wireworm as the receiver of heavy metals risk, biotope ecosystem as the receiver of soil erosion and coast risk; ecological indexes are calculated with species background index, biological diversity index and natural degree index, ecological friability indexes are calculated with soil fertility index, plant coverage, plant species diversity index, soil wireworm index and maturity index, and the typical coal mine area assessment indexes system is established. In addition, the regional ecological risk assessment is conducted on the friable ecological system of Fuxin Haizhou open coal mine area. Examples are researched of Haizhou open coal mine, the coal mine risk distribution is established, and foundations are provided for the administrative decision-making.

Water holding effect of subalpine dark coniferous forest soil in Gongga Mountain, China

Because of the distinction of soil property and humus content, soil water content is not ideal to indicate whether it is suitable to the growth of plant. Mainly based on the PF-a numerical value denoting the water regime of soil and connected with the growth of plant, the study combined the moisture percentage of soil with PF to research in quantity the interrelation between the moisture percentage and PF in different succession phases of subalpine dark coniferous forest in Gongga Mountain. The results showed that: (1) In the same PF value, the moisture percentage in humus horizon increased gradually with the development of the succession of the dark coniferous forest; The moisture percentage of over-mature forest was the highest and>mature forest>half-mature forest>young growth forest; (2) With the increase of soil depth, the soil bulk density increased and the moisture percentage decreased, but the difference in the percentage of moisture was not notable in different succession phases. (3) In different succession series, the vegetation affected the soil water characteristics by increasing the soil organic matter, improving the soil construction, receding the soil bulk density and enhancing the soil porosity; (4) The humus horizon of the dark coniferous forest soil has the highest water holding capability in this region.

Ecological adaptation of Eupatorium adenophorum populations to light intensity.

Eupatorium adenophorum is one of main invasive plants in China and has caused great economic losses. A study was conducted to determine the biomass allocation, leaf morphology and growth response of E. adenophorum seedlings that grew under five different intensities (relative irradiances RI 10%, 20%, 30%, 55%, 100%) for 14 months. Results reveal that the species shows typical leaf morphological adaptation to different light conditions. The total biomass of seedlings increased with the increase of light intensity from 10% to 55% RI but decreased at RI 100% (full sunlight). Height growth increased with the increase of light intensity from 10% to 30% RI but decreased when light intensity was over 30% RI. At low light levels, plants enhanced light availability by means of increasing biomass allocation to leaves and formation of larger, thinner leaves with high specific leaf area (SLA), leading to a high leaf area ratio (LAR) and high stem strips length (SSL). The mean relative growth rate (RGR) of the plant increased with the light intensity increase and attained the maximum at 55% RI. The growth of seedlings at 30%–55% RI was much better than that at full light condition. This might be an adaptive strategy that supports the vigorous invasiveness of this species, because a high-shaded canopy could prevent other plant species from surviving and growing. This study indicates that E. adenophorum could adapt to different light conditions, especially to low light habit. This can explain its greater invasiveness.

Evaluation model of the grey fuzzy on eco-environment vulnerability

The basic theory and evaluation index system of eco-environment vulnerability were reviewed. Based on the grey theory and fuzzy mathematics, a new comprehensive evaluation method from qualitative to quantitative, called grey-fuzzy evaluation, was proposed for evaluating eco-environment vulnerability. It was integrated of Association for Healthcare Philanthropy (AHP), grey correlation analysis, grey statistics and fuzzy judgment. The constitutional principle and method of the new evaluation method were given and its feasibility and effectiveness were proved by the practical example.