L’existence d’une veritable relique de foret dans le vallon de Daqinggou parait tout a fait en contrast avec le paysage desertique de ses alentours ou se succedent, a perte de vue, d’innombrables dunes plus ou moins mouvantes. Les plantes superieures de cette region, comprenant des elements des trois regions floristiques de Nei Monggol de la Chine du Nord et de Changpaishan, s’elevent a 450 especes. Dapres la fidelite et la presence definies dans la methode statistique de Braun-Blanquet, on y a releve 3 associations forestieres, a savoir, le Fraxinetum manshuricae, le Quercucetum mongolicae et l’Ulmetum macrocarpae. Parmi lesquels, la Quercetum mongolicae est le plus developpe au point de vue floristique, morphologique et structural, et le plus stable au point de vue de la dynamique. Sans etre influence par la nappe phreatique, il peut refleter l’etat moyen du climat regional sous la couverture forestiere. Il en resulte que sa genest n’est pas determinee par les conditions edaphiques particulieres, mais bien par le climat. Donc, il doit bien representer le climax climatique des communautes vegetales de la region. Quoique sa distribution soit actuellement tres restreinte,le fait que la regeneration naturelle du chene s’effectue un peu partout dans l’association de l’orme montre que dans le cours de l’evolution naturelle, le chene n’est pas en regression, mais bien en progression. Toutefois, par suite de la disparition de la foret depuis longtemps, le climat et le sol s’en trouvent relativement modifies en consequence. Donc, pour restaurer ou plutot pour reformer le visage naturel de la vallee du cours superieur de Liaoho, il faudrait bien considerer judicieusement la marche des,travaux de reboisement et le choix des essences a employer, et pour cela, la relique forestiere de Daqinggou pourrait fournir des indications tres utiles.

This paper recorded the destruction of natural vegetation at Baodao Xin Cun in recent thirty years, and its influences on the following aspects. 1. The vegetation is becoming lower and lower gradually, and the species of its composition fewer and fewer; the kinds of woody plant have been reduced to 102 as compared with that which is composed of 211 at the beginning of 1950’S. 2. Wild animals have become fewer as well, 21 species of birds have no longer existed. 3. The soil fertility is declining. As a result, the output of crop is decreasing and the outgrowth of natural vegetation is becoming poor year by year. In some quadrats, the fresh weight of plants above the ground is just over half of one kilogram per square meter. With the decling of soil fertility, some sciophiles specially fond of rich soil are dying away and some arid-enduring plants are sneaking in.

In this paper we have studied the effect of different light intensities on some photosynthetic properties of Setaria italica and Arachis hypogaea after shading treatment. The effects are expressed as follws The light compensation and saturation point of both crops are descended; Under lower light intensity, the rate of apparent photosynthesis and initial slope of light-photosynthetic curve are ascended; Especially, the rate of relative photosynthesis increases distinctly. Simultaneously, the chlorophyll and water content of the leaves are increased. The thickness of leaves becomes to be thin and the photosynthetic production decreased. The varying tendency of these characteristics is identical, but different on its extent. On the other hand, their apparent photosynthetic rates under the condition of light saturation, as the response to shading treatment, are quite different. Setaria italica is descended, while Arachis hypogaea is almost stable. According to the photosynthetic properties of these crops, it is clear that Setaria italica is a suny plant while Arachis hypogaea borderes on shade tolerant one. The shade tolerance of Arachis hypogaea is higher than that of setaria italica. Some data in this paper may provide a reference to arrange the structure of intercropping communities consisted by Setaria italica, Arachis hypogaea and some crops with tall stem, such as corn or sorghum.

Under climatic conditions of semi-dry and near warm temperate zone steppe in the eastern part of Ningxia, situated in the transitional region between typical steppe and desert steppe. There are different points of view concerned with the demarcation line between these two steppes. In accordance with structure and component of the vegetation, distribution and sere of Stipa bungeana and Stipa breviflora steppe. The demarcation line between these two steppes has been suggested. Besides, how to divide the line in the transitional region of steppe and its meaning in the use of grassland were described.

Jiangsu Province is situated at the sea board of Yellow sea, in latitute 30?46′—35?07′ north, longitude 116?22′—121 ?55′ east. It lies on the transitional area of warm temperate and subtropic zones, extending across southern temperate, northern subtropic and central subtropic bioclimatic belts. The annual mean temperature is 13–16℃, annual mean precipitation is 800–1200mm. There are uplifted hills and low mountains, which occupy about 5% of the total area, majority of them has an elevation of 200--300m. in general. The highest mountain in the area, Yun Tai Shan is mere at an elevation of 625m.By analysing the data, chiefly obtained by our own field survey, we recognize that, the basic characteristics of zonal vegetation in Jiangsu Province and its distribution pattern may be briefly summarized as follows:There are three typical zonal vegetation types in Jiangsu Province:1. The deciduous broad-leaved forestIt is mainly distributed in the north warm temperate region of the province and also may be seen in northern subtropic region. The basic constructive species for deciduous broad-leaved forest belong to the family Fagaceae, including Quercus variabilis, Q. fabri, Q. acutissima, Q. serrata var. brevipetiolata etc. In the calcareous hills, the species of Ulmaceae, such as Celtis bungeana, C. biondii, Ulmus pumila, U. parvifolia etc. are the characteristic species. 2. The deciduous and evergreen mixed forest It is widely distributed in the northern subtropic region of the province, but the typical form occupies the dotting hills along the edges of Taihu lake and the low mountains of Yixing and Liyang Districts, mainly in the central subtropic region. The basic constructive species for deciduous and evergreen mixed forest also belong to the family Fagaceae. The deciduous species are Quercus variabilis, Q. fabri, Q. acutissima, Q. serrata var. brevipetiolata etc. while the evergreen species are Castanopsis sclerophylla, Cyclobalanopsis glauca etc. Some calciphilous species such as Ulmus spp., Celtis spp., Zelkova schneideriana, Aphananthe aspera, Pteroceltis tatarinowii etc occurred on the calcareous hills. We consider that the deciduous and evergreen mixed forest type is a transitional form. This type is distributed overwhelmingly in the transitional area, the northern subtropic zone between warm temperate and subtropic zones of China, consequently it is distinguished with transitional characteristics, which are remarkably reflected by the development of mixed forest formation and its wide occurrence. 3. The evergreen broad-leaved forestIt is merely distributed in the central subtropic region of the province mainly in the mountainous regions of Yixing and Liyang Districts. The basic constructive species for evergreen broad-leaved forest are the evergreen trees of the family Fagaceae, such as Castanopsis sclerophylla, C. carlesii, Cyclobalanopsis glauca. C. myrsinaefolia, Lithocarpus glabra etc. In this forest, the deciduous spices are usually more in number than the evergreens, but the abundance and coverage of the latter are certainly dominant, therefore we consider that the evergreen broad-leaved forest type at the northern fringe of central zone is usually ,with some transitional characteristics. The principal types of three typical zonal vegetation types mentioned above are tabulated in detail. According to data of many plots, the dominant and frequent species, crown density distribution and habitat of all communities have been respectively generalized. Owing to having no high mountains the vertical zonation of vegetation does not exist. But the zonal vegetation types extending across three bioclimatic belts appear evidently. From north to south, the floristic component of zonal vegetation are gradually becoming multified, the number of vegetation types is increasing and zonal vegetation patterns occur successively in the order of the deciduous broad-leaved forest type, the deciduous and evergreen mixed forest type and the evergreen broad-leaved forest type. The typical zonal vegetation types of southern temperate, northern subtropic and central subtropic belts of China are tentatively designated as deciduous broad-leaved forest type, deciduous and evergreen mixed forest type and evergreen broad-leaved forest type respectively. The preceding two types containing the secondary vegetation, may also occur in northern and central subtropic belts respectively.