[Spatial pattern and interspecific association of tree species in coniferous and deciduous broad-leaved mixed forest under different disturbance intensities]. / ä¸åŒå¹²æ‰°å¼ºåº¦ä¸‹é’ˆé˜”æ··äº¤æž—æ ‘ç§ç©ºé—´æ ¼å±€åŠç§é—´å ³è”æ€§.

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. The results showed that the diameter distribution of trees in undisturbed plots was inverted 'J' type, while that of moderate disturbance and serious disturbance plots was under bimodal curve distribution. The stand distribution pattern showed a small-scale aggregated distribution under undisturbed and moderately distur-bance, and a random distribution under heavy disturbance. At the small scale, the coniferous and broadleaved species showed no correlation in undisturbed stands, were positively correlated in moderately disturbed stands, and negatively correlated in seriously disturbed stands. At large scale, they were no correlated in both moderately and seriously disturbed stands. The results suggested that abundance of trees with small diameter in the forests was negatively with disturbance intensity, which led to the lower degree of intraspecific aggregation at small scale. Meanwhile, appropriate levels of disturbance would benefit the collaborative use of environmental resources for trees. Our results revealed the impacts of disturbance density on forest community structure and could provide theoretical basis for forest management.

[Spatial distribution patterns and associations of typical tree species in different regions.] / ä¸åŒåŒºåŸŸå ¸åž‹æ ‘æœ¨çš„ç©ºé—´åˆ†å¸ƒæ ¼å±€åŠå ³è”æ€§.

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. Fagaceae had low abundance and a bimodal, skewed normal size-class structure respectively in CBS and GDS plots but a large number and an inverted J-type diameter distribution in HSD plot. Rosaceae had high abundance and a L-type size structure in GDS plot but relatively low abundance and a L-inverted and J-type size class distribution respectively in HSD and CBS plots. The trees from those three families showed different spatial distribution patterns in three different forest plots. The large size class individuals of Pinaceae were regularly distributed at small scale in CBS and GDS plots but aggregated in HSD plot, the middle and small size class ones were consis-tently aggregated in three plots. Fagaceae trees were mainly characterized by large size class and approximately distributed at random in CBS plot, but mainly characterized by middle or small size class and aggregated in GDS and HSD plots. The trees of Rosaceae were aggregated in three plots. The aggregation degree of trees from three families decreased with the increases of spatial scales. The large size class individuals of Fagaceae were negatively associated at small scale or uncorrelated with Pinaceae trees in CBS and HSD plots. The middle or small size class individuals of Fagaceae were negatively associated with Pinaceae ones in CBS and GDS plots but positively associated with Pinaceae ones in HSD plot. Trees from Pinaceae were negatively correlated with trees from Rosaceae in three plots. The middle or small size class individuals of Fagaceae were positively correlated with individuals of Rosaceae in CBS and GDS plots but negatively correlated with trees of Rosaceae in HSD plot. In conclusion, the spatial distribution patterns and associations of the trees from three families changed with the size class, research scale and had different patterns among three plots.

[Latitude variation mechanism of leaf traits of Metasequoia glyptostroboides in eastern coastal China]. / 沿海地区水杉叶片性状的纬度变化机制.

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. With the increase of soil N content, the SLA decreased firstly and then increased, while the leaf mass decreased significantly. With the increase of soil P content, the SLA increased, and the leaf mass decreased significantly.

[Variations in leaf C, N, P stoichiometry of Quercus acutissima provenance forests.] / éº»æ Žç§æºæž—å¶ç‰‡ç¢³ã€æ°®ã€ç£·åŒ–å­¦è®¡é‡ç‰¹å¾çš„å˜å¼‚.

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%-66.7% of the total variations accounted for leaf C, N, P, C/N, C/P and N/P, while the provenance effect was insignificant and only accounted for 2.9%-11.0% of total variations for leaf stoichiometry. The leaf N and C/N, N and N/P, P and C/P, P and N/P were significantly correlated, and the common standardized major axis slope was also observed among three sites and two provenance groups. It could be concluded that the leaf stoichiometry of Q. acutissima, was mainly determined by its growing environment, due to the similar C, N and P biochemical pathways at species level. The stable correlation coefficients among sites and provenances implied the coupling ratios of leaf stoichiometry were independent of environment and provenance, which supported the leaf stoichiometric homeostasis.

[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. In conifer stands, the distribution of Picea seedlings appeared as a patch pattern and was auto-correlated; while in mixed stands, the distribution was of gathering distribution pattern controlled by random factors. In the Picea stands with relatively low soil nitrogen content, the spatial distribution of soil available nitrogen was significantly heterogeneous and auto-correlated; whereas in the mixed stands with high nitrogen content, the distribution of soil available nitrogen showed random heterogeneity. In the conifer stands, the spatial correlation between Picea seedlings regeneration pattern and soil available nitrogen distribution was significant, regenerating more seedlings in the patches with higher NH4(+) -N concentration; while in the mixed stands, the correlation was not significant.

[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. The rate of postoperation complication was 22.9% and 27.3% in hepatectomy with or without portal vein resection and reconstruction respectively. The 1, 3-year survival rate were 85.7%, 31.4% and 81.8%, 27.8% in hepatectomy with or without portal vein resection and reconstruction respectively (P > 0.05). Only 5 patients were alive more than 3 years (7.58%), and no patient with palliative treatment lived over 5 years. CONCLUSIONS: Portal vain invasion is not the contraindication of resection for hilar cholangiocarcinoma. Hepatectomy with portal vein resection and reconstruction may raise the radical resection rate of hilar cholangiocarcinoma and improve the results of prognosis.

[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. The average age was 51 years old. The 41 patients had undergone gallbladder excision because of cholecystitis complicated lithiasis of gallbladder (32 cases), polypi of gallbladder or adenoma (9 cases). Postoperative pathology showed that 32 cases were adenocarcinoma of gallbladder, 6 cases were squamous carcinoma, 3 cases were squamous adenocarcinoma. Six cases were on the stage of Nevin I, 16 on Nevin II, 17 on Nevin III, 2 on Nevin IV. The second operation was performed after 6-30 d of the first operation. The second operation chose the improved method of Glenn excision of carcinoma of gallbladder. RESULTS: On the second operation, 14 cases were with lymphatic metastasis, 14 with gallbladder metastasis, 6 with bile duct metastasis, 2 with pancreas metastasis. Fourteen cases were on the stage of Nevin IV, 9 on Nevin V, none on Nevin I, II and III. After the second operation, 1 year survival rate was 100% (41 cases); The three-year survival rate was 53.8% (22 cases); The five-year survival rate was 17.5% (7 cases). CONCLUSION: Extended radical excision is one of the most important methods for the treatment of UGC.