Holdridge′s Life zone classification system is highly evaluated by international circles of ecolgy and environmental sciences owing to its simple and convenient for calculation and better correspondence with vegetation types. Recently it has been especially applied to assess environment, engage in ecological regionalization,predict the impact of global change upon ecosystems, etc. The result of analysis of climatological date for vegetation zones in China by means of Holdridge′s system also shows a significant correspondence. But, because it was developed in the tropical zone of Central America, an adjustment in China′s subtropical zone is needed. Nevertheless, the application of that system should be beneficiate for unification and comparative study of the climate-vegetation interaction in the world. The regression analysis shows a significant correlation between Holdridge′s potential evapotranspiration rate (PER) and radiative dryness index (RDI) of Chikugo Model. Therefore, PER could be used to estimate Net Primary Productivity (NPP). Its result of calculation for vegetation zones in China is satisfied and could be used to predict the change in vegetation zones, main types of ecosystems, and NPP in China.

The water relations of leaves for two understory shrubs, Rhodomyrtus tomentosa and Evodia lepta in a south subtropical forest were studied. The experiment was conducted at two sites in Ding Hu Shan mountain, Guangdong Province. The"open site" was on the top of back-hill near the office of Reserve Station, and the "middle site" was downwarded about 30m on the same hill. Stomatal conductance and water potential were measured by stable porometer(Li-cor 1600) and PMS pressure chamber respectively. Water potential components were calculated from pressure--volume curves.The daily courses of stomatal conductance in two plants from local time 7:00 to 17:00 showed a pattern of single peak. The time with maximum stomatal conductance in a day varied depending on seasons, it shifted to an earlier time from March to October. The highest average stomatal conductance was found in summer, and the lowest in winter. A midday depression of stomatal conductance was observed at the open site in August. In all cases at these two sites, and in nursery site, R. tomentosa had a higher stomatal conductance than E. lepta.Water potential went down from dawn and reached its minimum at noon, then raised back again in the evening. The trend of high water potential in March and August and low one in December was in consistent with the change of wet and dry season. Diurnal and seasonal patterns of water potential were not different between the two shrubs, but R. tomentosa possessed relatively higher water potential at dawn and midday than E. lepta in dry season.The relationship between stomatal conductance and leaf water potential was regarded as a hyperbola for this two plants. In August, the minimum water potential was still kept over the osmotic potential at zero turgor. No significant difference in the capacity of osmotic adjustment was found between the two species although they showed a different stomatal conductance pattern.

Qinghai Hoh Xil region is situated in the central part of the Qinghai-Xizang (Tibetan) Platean, the western side of the Qinghai-Xizang Highway between the Kunlun Mountains in north and the Tangkulashan Mountains in south (about 33˚52′—36˚16′ N lat.; 89˚24′—94˚04′ E long.). It is more than 80000km in size and the average altitude is as high as 4600—5000m while some peaks over 6000m. Most of this region is depopulateted because of its extreme elevation harsh climate, short growth period of forage grasses and difficulty for traffic. The mean temperature is lower than -5℃ in the whole year and lower than 6℃ in the hottest month, lower than -16—20℃ in the coldest month in most of areas of this region. The growing season of forage grasses is shorter than 100 days. The mean annual precipitation is relatively abundant with about 240--300mm in the eastern part and gradually reduced towards the northwest. About 69% of the total precipition falls in the three wormest months (June—Auguest) when plants grow. Soil is usually rough for its strong physicla effects and also week in biological effects. About 200 seed-plant species of 73 genera of 29 families have been noted in this region. Daisy family(Compositae), grass family (Gramineae),cabbage family (Cruciferae), and pea family. (Leguminosae) are the four richest species families. Families of grass, sedge (Cyperaceae), pea and daisy are the four most important ones in regetation composition. Stipa, Littledalea, Kobresia, Carex, Astragalus, Oxytropis, and Saussurea etc. are the most important genera. Almost 79% species are of Qinghai-Xizang Plateau geographic elements. About 69% species are hemicryptophytes the most adaptable lifeform to this kind of climate.Alpine steppe, Alpine meadow and alpine sparse vegetation are the main vegetation types. They occupy 51%, 14% and 26% of the total area respectively. Other types such as cushion vegetation, alpine desert, prostrate scrub etc. are also found. Generally the alpine steppe is distributed in the central part of the region, while the alpine meadow in the southeast and the alpine sparse vegetation in the northwest. This pattern of vegetation distribution is determined by the climatic factors. But vegetation distribution in some places is strongly affected by the following factors: landform, soil physical structure, soil moisture and soil salinity etc.

This paper reported such ecophysiological characteristics of eight species as efficiency of radiation utilization, transpiration coefficient based on vegetational research of limestone region and the results were compared with two species (Schima superba, Castanopsis fissa) of faster growth and often used for afforestation in non-limestone region. The infrared CO2 analyzer and steady state porometer model LI-1600 were employed in the study. The purpose was to select sortable species for afforestation of limestone region. The results showed that average photosynthetic rate (g CO2·m-2·d-1) were 19.92, 13.10, 9.04 and 8.11; utilization efficiency of photosynthetically active radiation (%) were 4.21, 4.59, 2.71 and 2.52; transpiration rate (g H2O·m-2·d-1) were 2191,1266,1479 and 1133;transpiration coefficient (g H2O·gDM-1) were 164,144,244 and 209,respectively, for Zenia insignis, Toona sinensis,S. superba and C. fissa. It also indicated that the ecological adaptation ability and photosynthetical productivity of Z. insignis and T. sinensis were higher than those of S. superba and C. fissa. The photosynthetical productivity of Cornus wilsoniana and Cinnamomum burmanni were similar to those of S. superba and C. fissa. The photosynthetical productivity of Radermachera sinica, Osmanthus fragrans, Sinosideroxylon wightianum and Castanea mollissima were low. However, the ecological adaptation ability of the six species (G. wilsoniana, R. sinica C. burmanni, O. fragrans, S. wightianum and C. mollissima) were higher than those of S. superba and C. fissa.

Woodwardia japonica and Hicriopteris glauca are often dominant species in the herbarous layer of broad-leaved evergreen forest in the Tiantong National Forest Park, Zhejiang Province. They show a great competing capability and a strong excluding force against other plant species in natural communities. This paper studies on the effect of maceration extracts of W. japonica and H. glauca on the budding and seedling growth dynamics of ten plant species, which include Schima superba, Lithocarpus glabra, Pinus massoniana, Cyclobalanopsis myrsinaefolia, Castanopsis sclerophylla, Castanea sequinii, Sassafras tsumu, Camellia oleifera, Loropetalum chinense and Camellia fraterna. The results show that the maceration extract of W. japonica can restrain remarkably the budding and seedling growth of C. sequinii, S. tsumu and C. oleifera, the restrictive effect on the seedling growth of P. massoniana is weakened gradually, but the maceration extract of W. japonica is promotive slightly to the seedling growth of S. superba. However, the maceration extract of H. glauca can restain the budding and seedling growth of most other species. The maincomponents of maceration extracts of these two ferns have been identified as alkene compounds(such as 3,7-dimethyl-l,6-octadien-3 ol, et al. contained in the extract of W japonica) by IR and GC-MS/DS.

This work measured the litter′s weight of every month in a year, the decomposing rate and the change of the major nutrient elements under subalpine dark coniferous forests in Wanglang nature preserve. The result shows:1) The total observed quantity of litter layers is between 29.97 and 91.76t/ha. 2)The litter weight changes slight for the different kinds of forests, with average about 2.8t/ha equally. The high withering seasons are May and October, which are the beganing and the end of the growth season. 3) In one year, the nutrients that returned to soil as litter are 35. 458kg, 5.71kg, 6.99kg, 62.89 kg and 6.78kg per hectare for N, P, K, Ca and Mg respectively. 4) The decomposing rate of litter is 0.3041g/g·year, t0.95 is 10 years. 5) In the time of litter decomposing, the releasing rates of nutrients are in the order of K>P>Mg>Ca>N.

The southern slope of mountainous area is an extremely difficult area for vegetative rehabilitation in the mountainous regions of North China. In this research, periodical and localized observations and measurements and ecological evaluation have been made on the moisture content, nutrient and gravels content of soil, formation of plant community, annual output of plants and their relative climatic conditions for eight types of southern slopes of mountainous areas. It is considered that the main barrier to vegetative rehabilitation on the southern slope of mountainous area is water, and that the moisture content of soil in mountainous areas over 800m in altitude is apparently better than that under 800m in altitude, but still cannot meet the requirements of large amount of water consumption of Chinese pine and locust trees. Hence, different ways should be taken for vegetative rehabilitation of southern slopes of mountainous areas at different altitudes. Amodel of forecast has been developed using quantitative analysis for the southern slopes of mountainous areas in Chengde district. It has been found that the major factors contributing to the net annual production of plants are in the following order, effective moisture content of soil, altitudes and thickness of soil layer. Various ways of vegetative rehabilitation are proposed accordingly.

Tilia amurensis is one of main planting-tree species in northeastern China and often forms mixed forest with Pinus koraiensis, Picea koraiensis, and Fraxinus mandshurica. Hence study on the influence of main associated tree species on growth of T. amurensis is important not only for the tree allelopathy, but also for selection of properly associated tree in building mixed forests of T. amurensis. This paper deals with results obtained from a lot of experiments on culture of T. amurensis in pots using the extracts of above mentioned tree leaves and their leaf powder mixed the soil. Experiment shows that leaves of Pinus and Picea negatively influences on growth of T. amurensis. But this phenomenon has not occurred in the experiment of Fraxinus leave-powders.

The tree introduction test results show that Taiwania flousiana seedling grows slowly and seedling growth curve appears to be "M" shape with double growth peaks, owing to the fact that it grows fast in spring and autum, but tends to stop in hot summer. During the initial stage of planttation, the young tree seedling grows slowly, but after 3 years it grows faster and faster and from the 5th to 10th year, it grows very fast. Annual growth of seedling is near or above its provenance growth. Seasonal growth reqularity of T. flousiana seedling is that it grows fast during the late spring and early summer (May and June), its growth peak appears in June, and then, the growth speed slows down in hot summer because of the high temperature, therefore the growth curve shows only one peak as a reversal “V” shape. Day-night growth of young T. flousiana seedling shows night> days the daily growth appears in that order: rainy day> cloudy day> shiny day. The following factors are the important ones which influence the young tree growth: air temperature, relative humidity and shining hours on the introduction locality. The relationship between young tree growth and seedling age could be expressed by the model of y =a+bt; the model y =a +blnt can be used to express the relationship between seedling growth and the observation month, and the average annual growth, annual increment and monthly net increment could be described by the model y=a+bt ct2.