Based on vegetation, climate, and soil, China’s deserts may be subdivided into three types: semi-desert (steppefied desert), true desert (typical desert) and extremly-arid desert. Each of these form a subzone of its own. From the southeast to the northwest, a series of subzone may be found: semi-desert-southeastern part of true desert-extremely-arid desert-northwestern part of true desert.Climatically, the semi-desert is semi-arid (with precipitation of 200—100mm), while the true desert is arid (100—50mm) and the extremelyarid desert is exceedingly arid (50mm).Due to the limiting factor of lack of water to all life processes and productive activities in desert areas, the possibilities and peculiarities of economic exploitation of the three types are different. For example, in semi-deserts, shifting sand dunes can be fixed by aerial seeding, but it is very difficult to do so in true deserts and impossible in extremely-arid deserts. In true deserts, the sand dunes might naturely be covered with grasses and herbs, but in extremely-arid deserts this never happens. Though the natural conditions of the latter are harsh and severe, if water is available, good agricultural harvests can be obtained.

This paper is report on the investigation of thirty sample plots in Fanjinshan’s bryophytes and elfin torest The results are as follows: 1. According to the distribution altitude, floristic composition the ratio of quantity to importance vuale between evergreen and deciduous trees and the life form spectrum, Fanjinshan’s elfin forest is regarded as a form of mixed forest of evergreen and deciduous trees. It is an orographic climax community. 2. Its special features are shown as: dwarfism with lower branches and no obvious trunk, bended shoots, close and level crown, slow growth, more mosses in its woods, floristic poverty, simple structure of layers and liana is rare. 3. The method of polar ordination is used to classify the coppice into six types: Rhododendron, Acer community, Prunus, Symplocos community, Acer community, Cyclobalanopsis stewardiana community, Sorbus, Rhododendron community and Buxus sinica community. 4.As the coppice has the character that germinative regeneration occupies an important place and the seed regeneration ability is weak, but the two modes of regeneration mutually complement to guarantee its regeneration, so it still is a stable community. 5. The basis of management is earnest protection for the Fanjinshan′s coppice.

This work was carried out at the Haibei research station of alpine meadow ecosystem in 1980. Not only the distribution range of the Kobresia humilis alpine meadow on the Qinghai-Xizang plateau is widespread, its quality is also excellent. It occupies a very important place in animal husbandry. We have investigated the allocation of the biomass and energy in Kobresia humilis meadow. We measured the biomass dynamics of above-underground by periodical harvest method, and the plants caloric values at different phenological stages were determined by JR-2800 bomb calorimeter. The result expressed: the biomass seasonal dynamics was obvious in Kobresia humilis meadow, the biomass of above ground varied with water and thermal conditions as well as growing development stages of the plants. The biomass above ground achieved peak value (296.66g/m2) on the 1st of September; Then the biomass gradual decreased until ceased before withering. The biomass of underground was medium durint the reviving period, minimum during flourishing period, maximum during the withering period. This concerned the growing development stages and organic matter transport. The plant’s caloric value in Kobresia humilis was maximum during flourishing period, medium during the withering period, minimum during the reviving period. The caloric values of plant groups: sedges was maximum, grasses medium, forbs minimum. The net primary production in Kobresia humilis meadow was 909.40g/m2·a; among others, aboveground part was 296.66g/m2·a; the underground was 596.67g/m2·a. and litter was 16.16g/m2·a; the solar energy storage of community was different in different growing period; the solar energy storage was maximum before the withering period. The utilization rate of solar energy in Kobresia humilis meadow was 0.295 per cent during the gowing season.

In this paper, the geographic distribution, growth nature and effects of soil and climate on Magnolia cylindrica, M. zenii, M. amoena, M. sieboldii and M. officinalis subsp, biloba were investigated.The results are summarized as follows: 1. M. zenii, M. cylindrica and M. arnoena are mainly distributed in East-China, usually growing in various broad-leaved forests. M. sieboldii is mainly distributed in North-east China and East-China, usually growing in bush-wood, while M. officinalis subsp, biloba is mainly distributed in East-China, South-China, and South-west China, usually growing in broad-leaved forests. 2.The growth rhythms:(1 ) M. zenii, M. cylindrica and M. denudata enter a rapid growth stage in the 3rd year. (2) A fast growth season of M. zenii, M. cylindrica and M. denudata occurs from May to July, while that of M. sieboldii is from May to June. (3) The growth in height is continuous both during the day and at night. 3. Plentiful precipitation, great humidity in the air and temperate climate are suitable for the growth of M. cylindrica, M. zenii and M. amoena, but M. sieboldii likes to grow in a cool, humid habitat. 4. These species of Magnolia are trees with great adaptability to acidity in soil with pH values of 4.5—7.5, and fertile, deep and humid soils with loose structure are more suitable for them 5.Their resistance to acid precipitation is weaker. 6. They can absorb and accumulate more Si and Ca in their growing process. The amounts of different elements in their leaves show obvious seasonal changes. The cyclic speeds of mineral elements in the growing process of M. zenii, M. cylindrica and M. denudata are similar.

In this paper, the litter decomposition rates of several plants have been studied, the results showed that the litter decomposition rates were different with different plants. The ratio of weight losses of the litter of Robinia pseudoacacia, Armeniaca vulgaris var. ansu, Platycladus orientalis, Acer truncatum and Cotinus coggygria var. cinenea for one year were 54%, 64%, 78%, 73% and 65%, respectively. According to the exponential decay model, the estimated litter decomposition rates of Robinia pseudoacacia, Armeniaca vulgaris var. ansu, Platycladus orientalis, Acer truncatum and Cotinus coggygria var, cinenea were 0.490g/(g·a),0.597g/(g·a),0.990g/ (g·a), 0.800g/(g·a) and 0.662g/(g·a) per year, respevtively. The chemical component analysis of the litters showed that the weight loss of the litters was due to the losses of gross fat, soluble sugar, tanin and organic carbon initially. The ratio of the carbon content and the hitrogen content of the litters decreased with the passage of time during the annual decomposing process.

This paper aims at exploring the application of the contingency table to phytogeographical research. By applying contingency table to exploring Larix potaninii distribution, the effects of both vertical altitude and latitude on vertical altitude interaction, latitude interaction as well as alternate interaction have been found, and that on the plant’s distribution has also been found. Because of allying using x2 test, analysis of residuals, order table association test, log-linear models fitting, the method of log-linear models fitting has been changed in some way. This preliminarily study proves that the contingency table may be successifully used with phytogeographical research.

Monsoon forest is a tropical forest-type, which part or most the upper canopy trees drought-deciduous during dry season of every year, or they are deciduous subdominant species in the tree crown. Monsoon forest is a forest-type of tropical climatic moisture gradient and a foresttype transition from tropical rainforest to tropical woodland. For this reason, the viewpoint of 《China Vegetation》 (1980), i. e. monsoon forest is the northeast type of tropical forest horizonal distribution, on the one hand it developing to tropical rain forest and on other hand also transition to subtropical evergreen broadleaved forest, were uncertain.Ficus formation and Endospermum formation in the lower subtropical region are not monsoon forests, they are the lower subtropical rain forests or the lower subtropical evergreen broad-leaved lowland forests. The single dominant Vatica formation is not monsoon forest but an edaphic climax of tropical rain forest in Hainan.