[Spatial pattern and interspecific association of tree species in coniferous and deciduous broad-leaved mixed forest under different disturbance intensities].

We explored the effects of disturbance densities on the spatial pattern and the association of tree species in the coniferous broadleaved mixed forest in Pangquangou Nature Reserve of Guandi Mountain. Using three factors including canopy density, stand density and number of stumps, we classified the disturbance intensities of different forest stands into three levels, non-disturbance, moderate disturbance, and severe disturbance. The spatial distribution pattern and the association of different tree species were analyzed by spatial point pattern K2 function.

[Spatial distribution patterns and associations of typical tree species in different regions.].

Based on the monitoring data from the plots of Changbai Mountains in the temperate zone (CBS), Guandi Mountain in the warm temperate zone (GDS), Heishiding Mountain in the subtropical zone (HSD), we analyzed the spatial distribution of tree species from three families (Pinaceae, Fagaceae, Rosaceae) and their correlation using paired correlation function g(r). The results showed that the individual number and size class structural characteristics of the trees from the three families varied among different regions. Pinaceae had high population density and a bimodal size-class structure in GDS plot but a small number and skewed normal size-class structure in CBS and HSD plots.

[Latitude variation mechanism of leaf traits of Metasequoia glyptostroboides in eastern coastal China].

We analyzed the rules of Metasequoia glyptostroboides along with latitude, including leaf length, leaf width, leaf perimeter, leaf area, ratio of leaf length to width, specific leaf area (SLA), and leaf dry mass based on eight stands growing at different latitudes in the coastal area of eastern China, as well as their relationships with climatic and soil factors. The results showed that the leaf length, leaf width and leaf perimeter increased with increasing latitude, while the leaf area and SLA firstly increased and then decreased. The mean annual temperature and annual precipitation were the major environmental factors affecting the leaf traits along latitude gradient.

[Variations in leaf C, N, P stoichiometry of Quercus acutissima provenance forests.].

In order to explore the variations in leaf stoichiometry based on the method of forest tree breeding, we determined the leaf carbon (C), nitrogen (N), phosphorus (P) stoichiometry among 29 Quercus acutissima provenances grown at 3 sites. The results indicated that the site (environment) effect was statistically significant on leaf stoichiometry, with 13.2%-66.

[Spatial relevance between natural regeneration of Picea and heterogeneity of soil available nitrogen in Guandi Mountain].

By using geostatistic and pattern analysis methods, this paper studied the spatial pattern of Picea seedlings in naturally regenerated conifer (Picea) and mixed (Picea-Populus-Betula) forests in Guandi Mountain of Shanxi Province, China. The spatial distribution of soil nitrogen was also quantified by semivariogram analysis. To understand the effects of spatial heterogeneity of soil nitrogen on the regeneration of Picea seedlings, the relationships between the regeneration pattern of the seedlings and the spatial distribution of soil nitrogen were investigated by using GIS superposition and statistical analysis.

[Hepatectomy with portal vein resection and reconstruction in the treatment of hilar cholangiocarcinoma].

Objective: To summarize the clinical experience and the role of hepatectomy with portal vein resection and reconstruction hilar cholangiocarcinoma.

Methods: From 1998 to 2003, the clinical records of 118 cases with hilar cholangiocarcinoma were reviewed.

Results: Of the 118 patients, 66 were performed palliative treatment; and 52 patients underwent radical resection, of which 47 patients, including 11 cases combined with portal vein resection and reconstruction, underwent hepatectomy.

[Analysis of the treatment of unexpected gallbladder cancer].

Objective: To investigate the secondary operation methods and the effects on the prognosis of unexpected gallbladder cancer (UGC).

Methods: A retrospective analysis on the clinical data was made for 41 patients who underwent extended radical excision from June 1995 to December 2002. Among the patients, 12 were male, 29 were female.