Chinese Journal of Ecology

Interspecific relationships of dominant tree species in Thuja sutchuenensis community.

GUO Quan-shui¹; WANG Xiang-fu¹; Bahaer Guli²; WAN Quan-xing¹

2007, 26(12): 1911-1917 .

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By the method of sampling plots investigation, the tree species composition of Thuja sutchuenensis community was studied, with the dominant tree species of the community ascertained by calculating the importance value. The overall association, interspecific association, and interspecific covariation of the dominant tree species were also studied. The results showed that an overall negative association was existed among 15 dominant tree species. The pairs with positive interspecific association were Quercus semecarpifolia-Carpinus fargesiana Q. semecarpifolia-Illicium fargesii, Cyclobalanopsis jenseniana-Q. phillyraeoides, Tsuga chinensis-Sorbus wilsoniana, C. cordata var. chinensis-Acer davidii, C. cordata var. chinensis-C. jenseniana, C. jenseniana-Macrocarpium chinense, and C. fargesiana- Illicium fargesii. The interspecific association of Q. semecarpifolia with A. davidii was negative, while that of T. sutchuenensis with other species was not significant. 26 pairs of species showed a significant positive interspecific covariation, and 12 pairs showed negative interspecific covariation. The similarity of environmental resources utilization could be the reason of the positive interspecific covariation.

Soil carbon mineralization potential and its effect on soil active organic carbon in evergreen broadleaved forest and Chinese fir plantation

WANG Qing-kui^1,2; WANG Si-long^1,2; YU Xiao-jun¹; ZHANG Jian^1,3; LIU Yan-xin^1,3

2007, 26(12): 1918-1923 .

Asbtract ( 2001 )

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With incubation test, this paper studied the mineralization rate and cumulative mineralized amount of soil organic carbon (C), and the correlations of the mineralized organic C with the initial content of soil active organic C in evergreen broadleaved forest and Chinese fir (Cunninghamia lanceolata) plantation in Huitong region of Hunan Province. The results showed that the mineralization rate and cumulative mineralized amount of soil organic C were significantly higher in evergreen broadleaved forest than in Chinese fir plantation. At the 21st day of incubation at 9 ℃ and 28 ℃, the cumulative mineralized amount of soil organic C at the soil depths of 0-10 cm and 10-20 cm in evergreen broadleaved forest was 1.7-2.7 times of that in Chinese fir plantation. The proportion of CO₂-C released from the mineralization of soil organic C was higher in evergreen broadleaved forest than in Chinese fir plantation. There were significant correlations between the mineralized amount of soil organic C and the initial content of soil dissolved organic C and microbial biomass C (P<0.01). The mineralization of soil C increased soil microbial biomass C while decreased soil dissolved organic C, but the increment or decrement was not too great. When the incubation temperature raised from 9 ℃ to 28 ℃, soil C mineralization rate increased 3.1-4.5 times, and less difference was observed in the responses of the mineralization rate to temperature change between broadleaved forest and Chinese fir plantation.

Reconstruction of temporal variations of precipitation in Changbai Mountains area over past 240 years by using tree-ring width data.

ZHANG Han-song^1,2; HAN Shi-jie²; LI Yu-wen¹; ZHANG Jun-hui²

2007, 26(12): 1924-1929 .

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Based on the tree-ring width chronologies of Fraxinus mandshurica in Changbai Mountains area, the relationships between tree-ring width and climatic factors were analyzed, and the temporal variations of precipitation in this area since 1765 were reconstructed. The results showed that over past 240 years, the precipitation in Changbai Mountains area fluctuated evidently. The amplitude of the fluctuation was comparatively great before 1850, and relatively stable from 1850 to 1900, with a low level of precipitation. After 1900, the amplitude of the fluctuation increased significantly, and the durations of wetness and drought were extended. Especially after 1920, the precipitation fluctuated acutely, and several wet and drought periods could be clearly identified. The driest period with an evident decrease of precipitation appeared in 1816-1820, and the wettest period was in 1975-1979. The drought periods which appeared from 1925 to 1936 and from 1947 to 1957 were particularly notable for their durations. There were significant periodical variations of precipitation in the Changbai Mountains area, and the periodicities were 2.64-3.03 years, 5.28-6.96 years, and 12.13-22.63 years, respectively.

Correlations between forest vegetation NDVI and water/thermal condition in Northeast China forest regions in 1982-2003.

GUO Zhi-xing^1,2; WANG Zong-ming¹; SONG Kai-shan¹; ZHANG Bai¹; LI Fang¹; LIU Dian-wei¹

2007, 26(12): 1930-1936 .

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The correlation between the monthly, seasonal and yearly mean NDVIs of forest vegetations and corresponding water/thermal conditions (precipitation and temperature) in Northeast China from 1982 to 2003 were analyzed. Results showed that, temperature was the primary climatic factor affecting the NDVIs. The mean NDVIs of various forest vegetations had significant correlations (P<0.01) with the temperature and precipitation in spring and autumn, and the correlation coefficient with temperature was higher than that with precipitation. For cool-temperate needleleaf forest, its NDVI had significant correlation (P<0.01) with the temperature and precipitation of growing season, the correlation between NDVI and precipitation was higher than that with temperature but was adverse for the whole year. The time lag partial correlation between NDVI of cool-temperate needleleaf forest and precipitation is higher in April, with a correlation coefficient of -0.385. For temperate needleleaf and broadleaf mixed forest, the time lag partial correlation of its NDVI with temperature was higher in April-July，with a correlation coefficient of 0.581，0.490，-0.266 and -0.297, respectively. For warm-temperature deciduous broadleaf forest, the time lag partial correlation between its NDVI and temperature was higher in April, with a correlation coefficient of 0.571, while the coefficient between NDVI and precipitation was higher in July with a correlation coefficient of -0.367. During growth period, the effects of water/thermal conditions (precipitation and temperature) on forest vegetation NDVI were lagged significantly.

Root propagation characteristics of Populus euphratica Oliv.

WANG Yong-bin¹; Nurbay Abdusalih¹; Niels Thevs²

2007, 26(12): 1937-1941 .

Asbtract ( 1982 )

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Taking young Populus euphratica forest at the northern floodplain in middle reaches of Tarim River as test object, and by the methods of excavation, high pressure washing and root-cutting, this paper studied the abilities of P. euphratica in sharing risks and in foraging and storing basic resources under heterogeneous resources environment, and the cloning characteristics of its root propagation from the viewpoint of cloning ecology. The results showed that the offshoot root of P. euphratica was uniaxial. The angle between two horizontal roots in the same growth direction was 180° on average, while that between vertical root and horizontal root was about 90°-100°, forming a T-shaped spatial structure. The mean perimeter of genets was longer than that of ramets, and the horizontal roots were frustum-shaped. There existed substance transfer between two horizontal roots of P. euphratica.

Community quantitative characteristics and dynamics of endangered plant species Abies chensiensis

ZHU Xiu-hong¹; LIU Guang-wu¹; RU Guang-xin¹; DU Yao-dong²;CHEN Chen¹

2007, 26(12): 1942-1946 .

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The community characteristics and dynamics of Abies chensiensis forest distributed on Shiren Mountain Nature Reserve were investigated. The results showed that the community was composed of 61 seed plants belonging to 27 families and 40 genera. The vertical structure of the community was simple which could be divided into tree layer, shrub layer and herb layer. The large and middle DBH class individuals of A. chensiensis and Pinus armandii were dominant. While seedlings and sapling classes were less which belong to declining population. The small DBH class and young trees of Sorbus hupehensis population were dominant which belong to progressing population. The results of quantitative classification showed that the community could be divided into 5 types: ①Ass. Abies chensiensis+Sorbus hupehensis-Rosa davidii-Zoysia japonica, ②Ass. Abies chensiensis +Pinus armandi-Rhododendron concinuum-Veratrum nigrum, ③Ass. Abies chensiensis+Acer griseum-Rosa xanthina-Dendranthema indicum, ④Ass. Abies chensiensis+Pinus armandi-Fargesia nitida-Arctium lappa, ⑤Ass. Abies chensiensis+Quercus acutidentata-Fargesia nitida-Oenanthe javanica. These five types are all in for the process of succession. It should be carried out the strategy for in situ conservation and reduced human interferences in the forest rehabilitation in order to accelerate the natural regeneration.

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