| Based on the methods of community Mathematics & Applied Statistics,the community characteristics of tsuga longibracteata pure forest,Tsuga longibrceata - Rhododendron forest and Tsuga longibracte ata-Cryptomeria fortunei forest were researched in Yong'an Tian baoyan national nature reserve. The studied including the sort of CCADCA; the distribution of the high scales and diameter scales and various kinds of model fittings; the spatial distribution patterns of the main species; species diversity features; main species niche characteristics and inter-specific association in tree layer; intra- and inter- specific competition comparison and community structural analysis.(1)From left to right,the order of CAA sort about three Communities was Tsuga longibracteata-Rhododendron,Tsuga longibracteata-Cryptomeria fortuneid and tsuga longibracteata pure forest. The first axis of DCA was significantly correlated with altituded,the Tsuga longibracteata pure forest was mainly located in the third and fourth quadrant in CCA ordination diagram; Tsuga longibracteata-Cryptomeria fortunei forest located in the fourth quadrant, Tsuga longibracteata-Rhododendron forest located in First and the four quadrants.The distribution patterns community was mainly affected by altitude and soil humidity, the distribution pattern of dominant species was mainly affected by altitude and ground temperature.(2)The research of DBH and high scale distribution showed that the DBH distribution of the tsuga longibracteata pure forest and Tsug alongibracteata- Cryptomeria fortunei forest about the number of individuals was decreased with the DBH increases;The share rate of DBH scale in Tsuga longibracteata-Rhododendron forest was decreased first and then increased. With the DBH increases, the share rate of tsuga longibracteata pure forest and Tsuga longibracteata-Cryptomeria fortunei forest was decreased first and then increased. Three frutex communities height-scale distribution was similar. The DBH was increased first and then decreased double, and then got to point in IV. The share rate of DBH scale in tsuga longibracteata pure forest and Tsuga longibracteata-Cryptomeria fortunei forest was increased first and then decreased two more, and then got to point in III&IV. But the share rate of DBH scale in the Tsuga longibracteata-Rhododendron forest was increased first incrersed and then decreased.(3)The research of main species spatial distribution patterns in Tsuga longibracteata showed that the tsuga longibracteata was followed aggregated distribution pattern, except tsuga longibracteata pure forest followed random distribution under 10m×30m scale .But with the scale increases, The Tsuga longibracteata-Cryptomeria fortunei forest was followed aggregated distribution, and then followed scattered trends with sampling scale increases; The Tsuga longibracte ata-Rhododendron forest was followedaggregated in all sampling scale.(4)Species diversity index of the order of the main species in tree layer is Tsuga longibracteata-Cryptomeria fortunei forest> tsuga longibracteata pure forest> Tsuga longibracteata-Rhododendron forest; which in shrub layer was Tsuga longibractea ta -Rhododendron forest > tsuga longibracteata pure forest > Tsuga longibracteata-Cr yptomeria fortunei forest; and in herb layer was Tsuga longibracteata-Cryptomeria fortunei forest > tsuga longibracteata pure forest > Tsuga longibracteata-Rhodode ndron forest;and Tsuga longibracteata-Cryp tomeria fortunei forest > tsuga longibra cteata pure forest> Tsuga longibracteata-Rhododendron forest in general. The first axis of DCA sorted sequence index continued to decline even after leveling off,but species diversity increased and then decreased.(5)The niche breadth in tsuga longibracteata pure forest was tsuga longibracteata higest> Cylobalanopsis glauca & Michelia maudiae & and Eurya japonica>Pinus; Castanopsis eyrei & Rhododendron simiarum.The niche breadth in Tsuga longibracteata-Cryptomeria fortunei forest was tsuga longibracteata >Lithocarpus glaber&Cylobalanopsis glauca&Fagus lucida>Cinnamomum micranthum. The niche breadth in Tsuga longibracteata-Rhododendron forest was Rhododendron simiarum > tsuga longibract eata & Cylobalanopsis glauca & Castanopsis eyrei> Lindera reflexa and Cast anopsis tibetana. Three communities exponential trend of niche overlap is different. With increase of ecological sections the Pianka Niche overlap index in tsuga longibr act eata was first increase then decrease, but got to one point between 0.4-0.6. And which in Tsuga longibracteata-Rhododendron forest and Tsuga longibractea ta-Cry ptomeria fortunei forest were relatively uniform in the first four sections,and smallest in the fifth section. The average of the niche overlap index order was Tsuga longib rac teata-Cryptomeria fortunei forest > tsuga longibracteata pure forest > Tsuga longib racteata-Rhododendron forest.(6)There were not significant negative correlation between main species nichechara cteristics and inter-specific association between the various communities. The contrast positive and negative species about tsuga longibracteata was 0.42. The correlation between Tsuga longibracteata and Rhododendron simiarum & Castanopsis eyrei & Michelia maudiae was negative, and Lindera reflexa & Cylobalanopsis glauca was positive, but not obvious. The contrast positive and negative species about Tsuga longibracteata-Cryptomeria fortunei forest was 0.86. The correlation between Tsuga longibracteata and Eurya japonica was positive,and Metasequoia glyptostroboides was negative,and Lithocarpus glaber was positive. The contrast positive and negative species about Tsuga longibracteata-Rhododendron forest is 0.42. The corre-l ation between Tsuga longibr-acteata and Rhododendron simiarum & Castanopsis eyrei & Michelia maudiae were negatives, and Lindera reflexa & Cylobalanopsis glauca was positive, but not obvious.(7)Three community species tend to bond with the distribution of species aggregation,and aggregation degree of the order was Tsuga longibract eata-Rhodod- endron forest> tsuga longibracteata pure forest > Tsuga longibracteata-Cryptomeriaf ortune forest. The recent genetic relation-ship species of Tsugalongibracteata- Rhododendron forest & Tsuga longiracteata-Rhododendron forest tend to aggregated distribution of tsuga longibracteata pure forest tend to dispersed. The aggregation level of recent genetic relation-ship species was Tsuga longibracteata - Rhododendron forest>Tsuga longibracteata-Cryptomeria fortunei forest> tsuga longibracteata pure forest. The order of phylogenetic diversity index community was Tsuga longibract- eata-Cryptomeria fortunei forest > tsuga longibracteata pure forest > Tsuga longibracteata-Rhododendron forest. There were significant positive correlation between phylogenetic diversity and species diversity index. Pedigree distance and niche overlap between species was significantly negatively...
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