There is a large area (about 5,900 hectare) covered with a primitive spruce forest in the sands at Baiyinaobao of Hexigten Banner in Nei Monggol. But which species this spruce forest belongs to is still a debatable problem in botanical taxonomy. The author has studied on this subject in different ways, which include investigation on the spot, identification of specimens, cultural experiments and analysis of geographic distribution.According to the research result, the species of the forest identified by the author is Picea meyeri Rehd. et Wils. This kind of spruce forest is a very rare and special type of forest ecosystem in the world. The detailed studies on phytocommunity characteristics provided scientific basis for improving the sands in western part of North-east China and eastern part of Nei Monggol and founding of a shelterbelts in North-east, North-west as well as North China.

The present paper deals with the secondary forest vegetation after 20 years period of natural regeneration. The field study was carried out on Mt. Wuchao near Hangzhou, Zhejiang Province. According to Jaccard’s community index of similarity, the secondary vegetation was divided into three types: the deciduous mixed forest, the evergreen mixed forest-a sere towards a higher stage of evergreen broad-leaf climax community, and intermediate type. The life forms were according to Raunkiaer’s classification:phaenerophyta (74.4%), chamaephyta (13.5%), hemicryptophyta (4.1%), geophyta (6.8%), and therophyta (1.4%). The high percentage of phaenerophyta is similar to the life form spectrum of the evergreen broad-leaf forest of Zhejiang Province. The leaf size of the vegetation was mainly microphylla (60.3%) but which is higher than those of the evergreen broad-leaf forest in other place of the province. 82.5% of the leaf pattern was simple leaf. The recovery vegetation stratification were divided into arborous layer, shrub layer, herbaceous layer and ground layer. According to Lutz’s phytograph index the most important tree species were:Lithocarpus glaber, Cyclobalanopsis glauca, and Quercus glandulifera var. brevipetiolata in which density, frequency, cross-sectional area and its appearence in the under and over story were predominant. Next is Castanopsis fargesii, Castanopsis sclerophylla and Schima superba. The recovery forest has a growing-stock of 50m3 per hectare, the highest is found to be above 140m3 per hectare. A total of 62 species of spermatophyta in 27 families and 45 genera was observed in the field during the study period and a comparison of its flora and geographical distribution was carried out.

Wanshan mercury’ mine region belongs to subtropical climate. By the analysis of mercury (Hg) concentration of soil, it shows that the mercury content has a significant variation. Hg concentration in the upper layer of soil is 2.33–420 mg/kg, but in lower layer is 2.03–27l mg/kg. As a result of long-period mining operations, the original vegetation had been destroyed and secondary vegetations were being formed. The grassland with scattered shrubs and shrubs are dominant vegetations in the mine region. The Hg concentration of main plants in 20 sample plots was analysed. It demonstrated the Hg concentration of the plants is different in various species; but the arrangemental positions of same species are similar in different sample plots. When the Hg concentration in the plants is less than 1.50 mg/kg, they are weak accumulator of Hg the plants of Hg concentration in range of 1.50 –3.50 mg/kg are intermedia accumulator of Hg; and Hg concentration is greater than 3.50 mg/kg those are the strong accumulator of Hg. Analysis demonstrated that Hg concentration of leaves is greater than that of branch in all wood-plants, then ratio of Hg concentration between leaves and branches is different in various species. The investigative data indicated that Hg concentration of all plants has largely increased under the condition of higher Hg level in air. Analysis manifested that some plants, such as Dendranthema indicum, Lespedeza davidii and Lindera flauca, in the Hg mine area have comparatively strong ability of absorbed and accumulated gaseous Hg, therefore, they may be used for purifying pollutant of Hg in air. The soil of farmland in the mining area contained very high Hg, as a result Hg concentrations of graincrop, vegetable and farm weeds were increased. It also clearly showed that the Hg concentration in rice was higher than that in the other graincrop; Hg concentration of vegetable in water farmland is richer than in dry farmland; Hg concentration of Polygonum hydropiper is the highest in farm weeds. The Hg amounts in non-edible part are much higher than in the edible part of the plants. The relations between the accumulation of Hg in plant community and the environmental factors are analysed. We found the accumulated Hg concentration of grass-plant and some shrubs are related to organic matter amount in lower layer of soil and the direction of slope. The Hg concentration in old branch was controlled by Hg content of lower layer soil and affected by soil moisture.

In this paper, the absorbing, transferring and accumulating law of mercury in the farmland soil-plant system polluted by mercury have been studied. The mercury content in soil within the range of 3 km from the pollution source was the highest. Mercury in soils distributed chiefly in 0–20cm surface layer, it almost did not move to the lower layer.The plants can absorb and accumulate mercury from the soils and air. The symptom of plants made by mercury pollution at Hangu have not been discovered. It was positive relationship between the mercury content in plants and soils. The correlation coefficient of mercury content in soils and in rice straw was 0.816(n=7), and the correlation coefficient of mercury content in soils and in brown rice was 0.898(n=7). The content of mercury in different organs of crops was as follows: root>stem>leave>seed; and compared with mercury content of the various crops seeds were as follows: brown rice> sorghum>wheat. In the air polluted area by high concentration of mercury, the mercury content of aerial part of plant was higher than that of root. Mercury of soils and plants was emitted continuously into the atmosphere, then it deposited on the soil surface or was absorbed by aerial part of plant. The capability of diffusion to adjacent area is Small.

The Mesopotamian Plain is the most important agricultural district of Iraq. Due to the arid-semi desert climate heavy texture silty-clay soils are dominant, the soils mainly contain sodium chloride and sodium, sulfate, magnesium and calcium.During the growth period of rice, the fields are usually covered with a layer of water which provides a better micro-climate condition in favor of the plant growth. Through the regulation action of evaporation, transpiration and frequent irrigation, the rice plant may pass its flowering stage more safely during the hot and dry season.After frequent irrigation, the salt content of soil is equilibrated at 0.15–0.30%. A 3-day drainage may solve the problem of contradiction of water to air supply, and keeps the salt content below the harm level also.The harm levels of salt content (mainly Cl-) to rice are 0.2–0.3%(0–5cm layer of soil) and 0.3–0.4% (5–20cm) during budding and rooting stage, and 0.5% (0–20cm) during three leaf stage.There is little change in soil pH during the growing period of rice.

The Shahe forest region is located on the area between 29˚8′45″—29˚13′30″N and 107˚31′—107˚35′45″E. The distribution of Cathaya argyrophylla ranges in elevation from 1400--1700m above sheer precipice and overhang rock, where the soil is deeper and the soil pH is between 3.4—4.6; the content of organic matter on surface soil is 4.8—20%, but on the lower horizon is 1.0—4.0%.Cathaya argyrophylla generally assembles in rather small pieces and grows with broad-leaved tree to form a mixed forest. The paper analysed and compared with the communities of Cunninghamia lanceolata-Quercus glandulifera var. brevipetiolata-Cathaya argyrophylla, Pinus taiwanensis–Cyclobalanopsis glauca–Cathaya argyrophylla as well as Lithocarpus hancei-- Quercus englcriana–Acer sinense--Cathaya argyrophylla, simultaneously, indicated that the main companions of relict Cathaya argyrophylla reflected characteristics of China--Japan forest vegetation subregion. Through analysing the biological characteristics of Cathaya argyrophylla found that its height in the period of growth increased most rapidly in the first 40 years and grew slowly 80 years later; the annual average height growth rate can be arrived 0.24m. Similarly, the diameter at breast-high in the period of growth increased most rapidly in the years from 40--70, and distinctly decreased 70 years later, the maximum annual average growth rate was 0.34m.

Cathaya argyrophylla is a famous Tertiary relic species and endemic in China. In recent years, it was discovered at the area of the northern part of Yuecheng Ling--the southwest of Hunan (locating in N, 26˚33′ and E. 110˚36′ at an altitude of 950--1050m.)and may be regarded as a news to the province. The mixed forest grows on the top of a cliff which is surrounded by a lot of the higher mountains at alt. 900--1500m. The area is isolated from human disturbance. So it can be survived to date. The compositions and the flora, the layers, the life form, the leaf size class and leaf texture are studied. The result shows that most life form are the chamaephyta and the microphyll with coriaceous texture. According the abundance, dominance and the frequence of the Stands the importance value index are calculated. Basis on the tree analysis of Cathaya the growth curve is given. The related communities in this area are also described.Some problems such as the reasons why Cathaya in this area can be survived, and why the cliff is the common habitat of all Cathaya forests everywhere, and the differences between Cathaya-Tsuga mixed forest in this area and the others are discussed.

The area of soil and water erosion in Shandong Province amounts to 44300km2, 79.3% of the total mountainous and hill regions in Shandong. Yi-Meng mountainous area is the most serious one in Shandong Province. Mengyin County is a typical case, the average amount of erosion soil in farmland is 2.09m3/mu/yr., resulting in a reduction of 3mm from soil layer.Destruction of the natural vegetation cover is the main cause of soil and water erosion. Other causes include reclamation, uncontrolled grazing, unreasonable overall arrangement of cultivated vegetation and unreasonable farming.Recovery of the forest is a fundamental measure for soil and water conservation. Besides, effectively controlling the soil and water erosion, prohibiting unreasonable reclamation, uncontrolled grazing and farming system, and carrying on effectively capital construction work on the farm are also necessary measures. Thus we can promote production and raise the living standard of the masses.

Xixia county on the south of the Funiu Mountains of Henan is in the northern part of subtropical zone of our country. It is an important base of the study on the forest vegetation. There are meso mountains, low mountains, hill lands, basins and valley plains in topography. The climate is of the transitional type from the subtropical zone to the warm temperate zone. The rivers have the characteristics of the mountain brook. The big rivers are the Lao-guan River, the Qi River, the Xia River and the Dan-shui River, etc. The principal soils are the brunisolic soil, the yellow-brown earth and the yellow cinnamon soil, etc.There are 5 principal types of the forest vegetation:The coniferous forest, the deciduous broad-leaved forest, the semiaiophyllus broad-leaved forest, the bamboo forest and the deciduous broadleaved economy forest. They include 10 formation groups and 18 formations, in which the Pinus massoniana forest, the Quercus acutidentata forest and the Quercus variabilis forest play an important role in the forest vegetation.A unity between the forest vegetation and the ecotype of Xixia county is an inseparable join and influenced part each other. The primeval physiognomy of the forest vegetation is fairly well. The forest covet degree was 75% before the War of Resistance Against Japan, and 63%, natural secondary forest 3, 230, 000mu, before liberation. Through the chop of the forest for 6 times the ecological equilibrium was destroyed: the rainfall decreased, the climate became dry, the water source dried up, the flow decreased, the water and soil were lose in large quantities, ponds and reservoirs and the course of rivers were bocked up, the animal had no place to live and proliferate, the agricultural production was influenced, the products of forest were decreased, etc. So we must be taking strong measures to adjust the forest vegetation of Xixia county.