The species diversity in different forest management models in Fujian Yong`an Forestry(Group) Joint-stock Co.,Ltd were studied.There were 222 species,113 genus and 72 families in the management area.The richness of species in 9 management models varied slightly with different growth forms.The richness of the shrub species was the highest,arbor was the second and the herb was the lowest.The species diversity under different models generally displayed as shrub layerarborherb.The species diversity and richness index were closely positive-correlative.By comprehensive analysis,species diversity of block utilization model was the highest,modification to enhance efficiency model was the second,the set-directed tending and replanting models were the worst,which demonstrated that the species diversity of natural forests was relatively high,while that of plantations was relatively low.

The spatial distribution of natural Rhododendron simiarum populations in Tianbaoyan nature reserve was studied by means of aggregated indices,Iwao model and Taylor equation,to provide theoretical reference for the management of natural R.simiarum forests and the protection of the resources.The results showed that: the aggregated indices,Iwao model and Taylor equation indicated that the distribution pattern of R.simiarum populations in Tianbaoyan nature reserve was aggregated,which was determined by the biological characteristics of R.simiarum population,inter-specific and intra-specific relationship,and the environmental conditions and so on.According to the Iwao equation,the theoretical sampling numbers under different densities and allowing errors were calculated.

Based on the investigation of the natural forests in Wuyishan Scenery District,the niche characteristics of 15 dominant populations were described and analyzed,with height class as the resource state and tree abundance as the index.The results indicated that the value of B(SW,i) and B(L) of Cunninghmia lanceolata,Castanopsis carlesii and Pinus massoniana took up the first three place,which showed that their distribution were relatively even in each height class.Meanwhile it also showed that they had a relatively wide resource utilization spectrum and the resources could be adequately used.In addition,there were 58 pairs whose niche overlap >0.5(including 0.5),the pair —— Adinandra mellettii and Machilus chrysotricha of which has the largest niche overlap value —— 0.935 9,indicating a high niche overlap could occur between two species with narrow niche breadth.

Growth dynamics of dominance of natural Pinus massoniana population in scenic spots of Wuyishan was detected based on the new growth model of population.Meanwhile a modified simplex technique was used to optimize the new model and the result showed that the actual maximum growth rate of the dynamics of dominance of natural P.massoniana population in scenic spots of Wuyishan was in the 6th diameter class and the breast diameter was from 20 cm to 24 cm.It would provide a theoretical basis for the protection and management of natural P.massoniana population in scenic spots of Wuyishan.

The log series model is applied to calculate and test the species abundance of natural forests in Wuyishan Scenery District. The forests are mainly composed of minority tree species and the tree individuals of majority tree species are few, indicating an unevenness in species abundance and a significant difference in species quantity in both arbor and shrub layers. The abundance grade of the arbor species ranges from 4 to 8, and that of shrub species from 2 to 4. Moreover, species abundance in arbor layer and shrub layer follows a logarithmic series distribution, and the species diversity of both layers displays the trend as Lithocarpus iteaphyllus>Cunninghmia lanceolata≥Castanopsis carlesii>Phyllostachys edulis>Pinus massoniana, which shows that the species diversity of the broad-leaved forest is more abundant than that of coniferous forest.

Niche characteristics of 15 major populations of natural forest in Wuyishan Scenery District were analyzed by quantitative method. The niche characteristics include niche breadth, niche proportional similarity and niche overlap. The results indicate that almost all the species investigated have narrow niche, with niche breadth (BL) of a few populations such as Pinus masoniana and Machilus chrysotricha0.54, and others BL0.4. In addition, niche proportional similarity index and Levin overlap index of all species pairs are high in sub-tropical forests.

Based on the data collected from continuous quadral grid through sampling method, the interspecific association of main populations in arborous layer of nature forest in Wuyishan Scenery District was analyzed by means of X 2-test and some indexes including association coefficient (AC) and Jaccard index (JI) and so on. The results showed that the overall association was significantly positive correlation among fifteen main populations and the interspecific association was not obviously correlation between most of species-pairs. There was closely positive association among some species-pairs such as Phyllostachys edulis-Schima superba, Adinandra mellettii-Cyclobalanopsis pachyloma, Cyclobalanopsis pachyloma-Distylium myricoides. There was closely negative association among 27 species-pairs such as Pinus massoniana-Cunninghmia lanceolata, Pinus massoniana-Cyclobalanopsis glauca, Cunninghmia lanceolata-Phyllostachys edulis, Cunninghmia lanceolata-Castanopsis carlesii, Cunninghmia lanceolata-Schima superba, Cunninghmia lanceolata-Adinandra mellettii and so on.