The expansion process of a Stellera chamaejasme population in a degraded alpine meadow of Northwest China.

The expansion of poisonous plants can change vegetation community structures and affect grassland ecosystem service values. Stellera chamaejasme is one of the most important poisonous plants and has rapidly expanded in the arid areas of Northwest China in recent decades. The objective of this study was to elucidate the expansion process and model of an S.

[Magnetic Responses of Heavy Metals in Street Dust of Typical Mine-Based City, Northwest China].

Magnetic characteristics and heavy metal properties of 43 street dust samples collected from Baiyin City, northwest of China were systematically analyzed. The results revealed that the main magnetic minerals were low-coercivity magnetite and maghemite with coarse pseudo single domain (PSD) and multi-domain (MD) in magnetic grain size. Compared with the domestic comprehensive cities, low frequency magnetic susceptibility(χlf) value of street dust samples in Binyin varied from 43.

Ozone uptake by adult urban trees based on sap flow measurement.

The O(3) uptake in 17 adult trees of six urban species was evaluated by the sap flow-based approach under free atmospheric conditions. The results showed very large species differences in ground area scaled whole-tree ozone uptake (F(o)₃), with estimates ranging from 0.61 ± 0.

Transpiration rates of urban trees, Aesculus chinensis.

Transpiration patterns of Aesculus chinensis in relation to explanatory variables in the microclimatic, air quality, and biological phenomena categories were measured in Beijing, China using the thermal dissipation method. The highest transpiration rate measured as the sap flux density of the trees took place from 10:00 am to 13:00 pm in the summer and the lowest was found during nighttime in the winter. To sort out co-linearity, principal component analysis and variation and hierarchical partitioning methods were employed in data analyses.

[Magnolia liliiflora whole-tree sap flow in response to multiple environmental variables in Beijing].

In order to clarify the environmental factors affecting the water use of typical urban tree species Magnolia liliflora, an investigation was conducted on the responses of M. liliiflora whole-tree sap flow to the air temperature, air relative humidity, radiation, wind speed, soil temperature and water content, and precipitation in Beijing from April to October, 2008. The eight environmental factors affecting M.