The evergreen broad-leaf forest of trees of the Castanopsis kawakamii species is located in the Wakeng area of Sanming City(117˚20′E,26˚10′N), Fujian Province, on the southern boundary of the mid-subtropical region in China. The floristic composition of the communities in 31 plots totalling 3100m2 in area consists of 139 species of vascular plants, 52 families and 90 genera. Of the 90 genera, 75.6% are single species genera. Analysis of floristic geographical elements indicated that the percentages of tropical and pan-tropical elements are high, making up 61.5% and 67.8% of the total numbers of families and genera respectively. The physiognomy of the communities was analyzed on the basis of the life forms of the plants and their leaf characters, which showed this forest was a transition type from south-subtropical rain forest to mid-subtropical laurilignosa(evergreen broad-leaf forest).The homogeneity and Shannon-Wiener’s index of species diversity of Castanopsis kawakamii forest were 20.9342% and 4.3992 respectively. Analysis of the age structure of the trees of the forest showed that it was a community of relative stability.

The present paper is a study of the relation between the zonal distribution of types of vegetation and the climate in Northeast China, based on the method of Kira’s temperature indexes WI, (Warmth index),CI, (Coldness index) and the HI (Humidity index) proposed by the present author. The results are asfollows:1. The optimum range of warmth index and the value of warmth index, coldness index and humidity index of 10 types of zonal vegetation in the Northeast China have been determined. 2. The vertical distribution features in water-temperature conditions of zonal vegetation types on mountains in Northeast China have been studied. On the basis of the above studies, the paper has discussed the problems about the distribution of Betula ermanii forest zones on the eastern mountains in Northeast China and that of the mountain tundra on the Baigalashan mountain in the Da Hingganling and made a new attempt to divide the vegetation regions in Northeast China.

Glycyrrhiza uralensis, G. glabra, G. inflata, G. aspra and G. korhsinskyi are 5 species of Glycyrrhiza. Which distribute in 63 counties of Xinjiang. The area of G . inflata is Talimu Basin. The area of other 4 species are Mediterranean-Central Asian. According to author’s analysis, the climatic requirements of genus Glycyrrhiza in Xinjiang are the mean annual precipitation of 4—490mm, the mean annual of temperature of 0.4—14℃, the annual accumulated temperature of 1900—5500℃. But the ranges vary with different species.In order to have a sustainable and complete utilization for liconice, a rational excavation system should be set up and a special licorice productive base should be established, and, last of all, an integrative utilization system has to be developed.

The plant population pattern is a real charocteristic in a forest community. Like all statistical methods used in the study of the phytocoenology, the results of the testing and analysis of the plant population pattern depend heavily .on the field sampling method used with the community. In three different communities in the Ding Hu Shah natural reserve, Guangdong, China, the following five methods were applied to the sampling for information on plant species distribution: 1. Random quadrats, 2. contiguous grid quadrats (Greig-Smith, 1952;Kershaw, 1957), 3. point-centered quarter(Bray, 1962), 4. nearest neighour(Clark and Evans, 1954) and 5. closest individual (Pielou, 1959).The comparative studies dealing with the arrangement of the field data, the pattern testing and the pattern analysis showed that method 1. was affected by the quadrat size, although it can be used with all the communities. The use of the plotless methods is limited in the evergreen broad-leaved forest. The method 2. was an effective one with every community not only for pattern testing but also for pattern analysis. The various methods gave different testing results with one and the same in a community, while each method presents a difference in adaptation to different communities.The results of the research suggests that method 3. is insensitive to the departure from random dispersion, method 4. and 5. are suitable to the mono-dominant community, and the contiguous grid quadrats method is a multi-purpose approach that can be used widely for the research of plant population pattern in a subtropical forest community.

Masson pine (Pinus massoniana) is one of the pioneer species of the subtropic forest succession and of all the secondary succession stages on, the Jinyun Mountain,which is situated in the northwest of Beipei district Chongqing city, Sichuan Province (29˚50′N,106˚26′E). The study on the quantitative dynamics of Masson pine population is of great significance for studying the forest communities and ecosystems in subtropic China.The use of the plot-chronosequence provides a short-cut method for studying the population dynamics of long-lived plant species. Bfore the age of seven, the density of a Masson pine population in the mountain increases and the rate of its growth decreases with the passage of time. And beyond that age, the density decreases and the rate of growth increases with the passage of time. The density would continue to decreases even after 30 years, but the rate of growth would increase markedly with the lapse of time.In the period between shrub-grassland and Masson pine forest, the dynamics of population biomass shows a logistic growth, i.e. where A is the population’s age in years Bp is estimation of the population biomass in t.ha-1. In the period between the coniferous broad-leaved mixed forest and the evergreen broadleaved forest, the population biomass decreases with the time passed. The relationship between the populational density and the mean plant biomass during the self-thinning accords .with t he-3/2 thinning power law and can be described as,where, Bi is mean plant biomass in kg, D, populational density in trees.ha-1. The obvious factor resulting in the quantitative dynamics of Masson pine population at the mountain is the self-thin-ning caused by intraspcoific competition and the alien-thinning by interspecific competition for the light resource in the stand.

Biomass of 14-year old Masson pine timber stands of different densities (2445–4590 trees/ha) was estimated in the hilly area in central Guangxi Province. The results show that the average biomass of individual trees decreases with increasing density within the range of given densities, Biomass of the stands was highest at Ⅱ density group (3210 trees/ha) on the contrary. On the other hand, the annual litterfall increases with increasing density, and the total accumulation of nutrient elements within litter layer increases also with increasing density.

This paper is aimed to discuss the reason of decline and the way of regeneration from the relation between the Populus euphratica and its environment in the Tarimpendi (basin). The invasion of this plant community usually are dominated by the overflowing floods of rivers. In the arid climate, these consociation forests depend on the underground water for their growth, and can’t regeneration naturally. The biotopes of community are determined by the life cycle of individuals in the forest. Since in the desert zone the river courses are often changing, hence its distribution range is maintained in a dynamic stable state. In recent decades, the base of life of Populus euphratica was shaken, as a result of the changed flood factor; moreover the declining is further intensified by forest denudation. The efficiency of the coppice wood growing from the stumps of lumbered trees is low. If these stumps are dug up, young shoots may grow out vigorously from the underground roots remaining in the soil, and the trees grow up as cuttings;hence this may be an effective way for regeneration and rejuvenation of Populus euphratica forests.

Baizha forest region located in the southeastern Qinghai-Tibetan Plateau is the border of the high-mountain coniferous forest distribution. The plant species and structures are simple. This region is a transition zone from forest vegetation to high-cold scrub and meadow In a certain sense, this paper represents some of the characteristics of the intermediate state of Qinghai-Tibetan Plateau vegetation between forest and meadow.