In this paper, the contents of protein, fat and starch were compared among Kobresia humilis plants grown at different altitude in Qinghai-Xizang plateau (Daban Mt, 4,000 m a.s.1; Jinyang Mt,3,800 m a.s.1;Haibei station, 3,200 m a.s.1;Xining,2,200 m a.s.1). The results show that some biochemical component in aboveground and belowground tissues of the plants tended to increase with increasing altitude. As compared with those plants in Jinyang Mountain, Haibei Station and Xining, on average, the plants grown at Daban Mountain had a higher protein content by 9.9% ,17.3% and 39.4%, a higher fat content by 7.5% ,77.8% and 106.8%, and a higher starch content by 2.4%, 21.6% and 32.7% ,respectively. It is clear that altitude had effects on the seasonal changes of the contents of some biochemical components.The results suggest that the stronger frost resistance of the plants located at a higher altitude are associated with their stronger synthesis of the protein, fat, starch and related substances.

The area of the Karakorum-Kunlun Mountains is not so rich in flora. 827 species, subspecies and varieties of higher plants were recorded in the area of ca. 400, 000km2. Those plants belong to 272 genera of 60 families. Among them there are only 5 fern species of 3 genera of 3 families and 14 gymnosperms of 3 genera of 3 families. There are 136 grass species (Gramineae). The families each of which have more than 50 species observed there were Compositae, Leguminosae, Cruciferae, Cyperaceae and Chenopodiaceae. Of the taxa in the area, 44.5% belongs to the Central Asian geographic elements and 21.7% to Qingzang Plateau elements in terms of genera. But the Qingzang Plateau elements dominated in the sections of the Kumkol Basin of the Middle Kunlun (see Fig. 1 Ⅰ 5), the southern flank of east part of the West Kunlun (Ⅱ 2) and the southern flank of the Middle Kunlun (Ⅱ 3). The higher the altitude of the belts is, the greater the proportion of Qingzang Plateau geographic elements is . The proportion of Centra Asian elements decreases while the proportion of the Qingzang Plateau elements increases as the altitude raises. These two elements are similar in proportion at ca. 4250 m above sea level. The floristic differentiation between the southern and the northern flanks of the Kunlun is much more apparent than that between the West and Middle Kunlun. The results of this study show that the demarcation line between the Central Asian sub-region and the Qingzang Plateau sub-region runs along the Karakorum-Kunlun Mountains.

A vast amount of material and literature of the horizontal and vertical distribution of dominants, main companions of subtropical evergreen broad-leaved forest in China waere collected. 112 dominants and main companions, including 14 families, were selected to study the relationships between the climate and the vegetation. Those families were Myricaceae, Juglandaceae, Fagaceae, Magnoliaceae, Lauraceae, Theaceae, Hamamelidaceae, Daphniphyllaceae, Elaeocarpaceae, Araliaceae, Styracaceae, Aquifoliaceae, Frieaceae and Symplocaceae, respectively. Kira’s warmth index (W I ), Coldness index (C I ) and Xu’s humidity index (H I ) of those 112 kinds of dominants and main companions were calculated. The groups of Kira’s water-temperature distribution of main species of subtropical evergreen broad-leaved forest in China were classified into five types.Penman’s potential evapotranspiration (PET) and aridity (A) of the dominants and main companions were calculated. The groups of Penman’s water-temperature distribution of main species of subtropical evergreen broad-leaved forest in China were classified into five types, too.Thornthwaite’s potential evapotranspiration (APE), humidity index ( I H), aridity index ( I A) and moisture index ( I M) of those 112 kinds of dominants and main companions of subtropical evergreen broad-leaved forest in China were calculated. The groups of Thornthwaite’s water-temperature distribution of the dominants and main companions were classified into five types.Holdridge’s biotemperature (BT), potential evapotranspitation (P E), precipitation (P) and potential evapotranspiration ratio (PER) of the dominants and main companions were calculated. Holdridge’s water-temperature distributional groups of main species of evergreen broad-leaved forest in China were classified into five types too.

Based on the static life table , fecundity schedule of Picea mongolica population, the dynamic process of the spruce population, which is representative in Baiyinaobao, Xiaotengeli sandy lands, Inner Mongolia, was predicted using Leslie population model. The dynamics of plants of each age class was expounded. The spruce population on the sandy land was of low increase type. Its net reproductive rate, the intrinsic rate of increase and the increment rate per unit were high, but its generation span and the time of double population size were low. The number of one-year-old plants and total number of plants increased continually, and the change of total number of plants was small in 50 years.

Schima superba is one of the dominant species of subtropical evergreen broad-leaved forest in East China. This study was carried out on Mt. Wuyi, with the method of spatial sere substituting for time sere. On the basis of a census of all individuals of S. superba population at different successional stages, size structure, spatial pattern, population density and population dynamics were described for the species. In the early period after S. superba population invaded the Pinus taiwanensis forest, size structure of the population was characterized by a growing type, while the spatial pattern of the population showed a random type. In the process of development from P. taiwanensis forest to mature forest dominated by S. superba and C. eyrei, the size structure of the population tended to be stationary. Afterwards, it tended to be mature and senescence. In the meantime, the spatial pattern tended to be contagious type, and population density was continuously decreased. In the stages of the mature forest, the structure and density of the population had a process of fluctuation accompanying the regeneration or rehabilitation through forest gaps and the spatial pattern of the population also followed a contagious type. In addition, the spatial pattern of different size classes of the population was studied in the mature forest. It was found that the seedling, sapling and middle tree classes showed contagious type while the large tree class exhibited random type. Because the forest gaps could emerge commonly in the mature community, the population could maintain a relative steady state in a long period of time. According to the results above, the dynamic mechanism of S. superba population was discussed.

Based on the previous works, a general model for neighborhood interference index has been put forward: And the methods of measuring growth rate, neighbor size and target individual size have been discussed. As an example, the general model was applied to the management of Pinus massoniana forest.

In the present paper, tree rings of Pinus tabulaeformis were sampled in the Summer Villa Estate of Chengde City, and their δ13C values were measured using a MAT-252 isotope ratio mass spectrometer, in order to reveal the historical changes of atmospheric CO2 in North China. The results show that, since 1810, the δ13C values in the tree rings of P. tabulaeformis have decreased by 0.839‰ with a range of 0. 682‰～1.120‰ ,indicating that the concentration of atmospheric CO2 has increased. There was a good linear correlation between the values of tree ring δ13C and the historical global atmospheric CO2 concentration (r = – 0.5609, p<0.01). By applying the formula of tree ring δ13C with concentration of atmospheric CO2, we estimated that CO2 concentration in North China has increased from 278.4 μmol·mol-1 in the preindustrialization to 340 μmol·mol-1 at present.

Fire is one of the major environmental factors in forest and grassland ecosystems. Based on the results of analysing charcoal, pollen and loss-on-ignition (LOI) in 15000 a B.P. sediments in Dongganchi, this paper deals with the possibility of fire occurring since 15000 a B. P. in Beijing. The time series analysis was used to infer patterns of fire as well as relationship between fire and some plants. In the meantime, other factors resulting in fire were considered. In addition, the man’s effect on fire playing was discussed according to archaeological and historical material.

73 Garlic varieties collected from the area in 22˚～45˚ N and 77˚～127˚ E could be classified into 3 ecotypes by experimental and numerical taxonomy, the difference in number of leaves between autumn and spring seedeing was the main character by which the classification was made. It reflects the sensitivity of scaly bud and inflorescence differentiation to low temperature. The 3 ecotype were Low Temperature Sensitivity Type (LTST), Low Temperature Middle Type (LTMT) and Low Temperature Inactivity Type (LTIT). The difference is larger in LTST collected from the area at latitude 31˚N and more southern. The plants grew rapidly in winter and were less tolerant to coldness. The difference was smaller in LTIT collected from the area at latitude 35˚N and more northern or at low latitude but high altitude. The plants grew slowly in winter and were endurable to coldness. LTMT collected from area of latitude 23˚～39˚ N behaved between LTST and LTIT in terms of the difference.

The growth rule of root system of winter wheat in semiarid red clay soil hills in west Henan was investigated during 1987～1993. The results show as follows: the growth of primary and secondary roots and root number tended to increase with prolongation of the growing of root system, the maximum depth of the root system can be 340 cm, the increasing equation of root biomass (Y, kg·mu-1) is Y=33.013-2.732X+0.0902X2-0.000999X3+0.00000466X4- 0.00000000770X5, which has two peaks before overwintering and duration from rising to jointing respectively. The distributions of the root number and biomass inside soil were in keeping with the equation Y= ae-bx. When soil water capacity was bigger than 16 %, the growth of root system and aboveground part was all abnormal. The function relationship between root depth and soil water capacity around root tips can be described with equation Y= 2.009e0.2204X. Appearing of secondary root was not corresponding with number of leaves on the stem but with tillering. The dry matter accumulation of root system was in coordination with aboveground part. The increasing of primary root number can improve ear/plant. The increasing of secondary root number can raise grain/ear and weight/1000 grain. The improvement of root growth and yield due to soaking seed with microelement fertilizer or hormore was significant.

Recreation ecology is a new area of ecological application. Xiangshan Park is a famous scenic spot near Beijing. The tourists in this park centralized in both temporal and spatial aspect. In this paper, the degree of recreational disturbance was determined by the road situation. The effects of recreational disturbance on the characters of population, community and soil in the Cotinus coggygria var. cinerea forest (also named red leaf forest) which is the most important recreational resource in Xiangshan park, were studied. The results of this paper can be used for recreational ecological planning of this park.