Natural Closeness Assessment And Biotope Mapping Of Forest Communities In Huoditang Forest Region In Qinling Mountain

Natural closeness assessment and biotope mapping were the basis of the close to natural forest management and they also could propose reasonable advice for management measures. 7,8,9,10,11,12 small classes in13 stand compartment were selected to build Experiment and Demenstration Site in Huodintang Forest Region. Through the sample investigation, vegetation composition, spatial structure, succession stages and characteristics of the soil of different forest communities were analyzed and researched in Huoditang Experiment and Demonstration Site in Qinling Mountain. On this basis, through sensitive analysis of 30 indexes which description the community characteristics, 18 indexes were filtered out and used to construct index system to assessment the natural closeness. AHP was applied to evaluate the natural closeness. ARCGIS software was used to biotope mapping. The results showed that:1. In Huoditang Experiment and Demonstration Site,the total area of Experiment and Demonstration Site were 27.6 hm2. Vegetation resource was abundance and was divided into 41 families 71 genus 84 species. 9 families 14 genus 18 species in the arbor layer, 18families 36 genus 41 species in the shrub layer and 23 families 30 genus 31 species in the herb layer. All vegetation were divided into seven communities: Pinus armandii and Tsuga chinensis community, Larix gmellini and Betula albo-sinensis community, Larix gmellini community, Betula albo-sinensis community, Tsuga chinensis community, Pinus armandii community and Pinus armandii and Cephalotaxus sinensis community.2. Species diversity of different communities had shown a similar trend, shrub layer> arbor layer> herb layer; Larix gmellini community both in arbor layer, shrub layer or herb layer, the diversity index is the lowest. The richness index of Pinus armandii and Tsuga chinensis community both in the arbor layer, shrub layer or herb layer was the highest, and its Simpson index and Shanon-Wiener index in the tree-and shrub layer has also reached the highest. Pielou evenness Index (Jsw) of Tsuga chinensis community was the highest in arbor layer and the value was 0.9793. Four diversity indexes of Pinus armandii and Cephalotaxus sinensis community were highest in shrub layer and the values were 25,0.7881,2.6379 and 0.7941. Note the shrub layer developed, the species richness. The difference of Pielou evenness Index among seven communities was not significant, other diversity indexes differences were significant.3. The spatial distribution pattern of stand, Tsuga chinensis community and Pinus armandii and Tsuga chinensis community were clump distribution, Betula albo-sinensis community and Pinus armandii and Cephalotaxus sinensis community.were random distribution, Larix gmellini community and Pinus armandii community were evenness distribution. From plantations to secondary forest, with the succession progress, The stand distribution developed from evenness to random to clump distribution. The mixed degrees of the tree species also showed gradually increasing trend from the natural forest to plantations. In the vertical structure, the tree layers of the secondary forest were very clear and significant differences, but which of the plantation were single. Secondary forest was different aged stand. Plantation was same aged stand. Through analysis of the DBH structure, Tsuga chinensis population belonged to progress population, Pinus armandii population belonged to reaped and stable population, Betula albo-sinensis population belonged to stable population, Larix gmellini population belonged to recession population.4. The regeneration of Tsuga chinensis community and Pinus armandii and Tsuga chinensis community were Tsuga chinensis saplings and their numbers were rich. Which number were 2775/hm2 and2355/hm2. The regeneration of Betula albo-sinensis community were Betula albo-sinensis which were pioneer species and Acer davidii which were transitional species. The regeneration of Pinus armandii and Cephalotaxus sinensis community were Cephalotaxus sinensis saplings. The regeneration of Pinus armandii were Betula albo-sinensis, Acer davidii, Tsuga chinensis. The regeneration of Larix gmellini community were Tsuga chinensis and Picea wilsonii. The ability of regeneration was very weak and could not regeneration by themselves.5. The CI Values of seven communities were 5.01, 2.14, 1.75, 6.48, 3.22, 2.67 and 4.12, respectively, and the values of hemeroby of the seven communities were 9, 2, 1, 9, 5, 3 , 7. The order of succession were : Larix gmellini community→Larix gmellini and Betula albo-sinensis Community→Pinus armandi plantation community→Betula albo-sinensis community→Pinus armandii and Cephalotaxus sinensis community→Pinus armandii and Picea wilsonii. community→Tsuga chinensis community.6. Soil fertility greatly impact on the community. The difference of soil density and soil pH value among seven communities were not significant. Urease, organic matter, total N, available P, K and capacity exchange of Larix gmellini community declined significantly compared with the highest content of these indicators of Tsuga chinensis community, in the 0 ~ 20 cm soil layer, which of Larix gmellini community declined 50.7%, 49.5%, 25.1%, 68.7%, 54.0%, 48.8%, in these indexes , The most obvious declination were available P, followed by the available K, organic matter content and capacity exchange, the lowest decline was toatle-N.7. Through sensitive analysis of indexes, selected 18 evaluation indexes are: arbor layer species richness, shrub layer species richness, arbor layer Shanon-Wiener index, arbor layer Pielou eveness index, shrub layer Pielou eveness index, Mixed degrees, the number of regeneration, the number of age-class, the average diameter of constructive trees, high classes of constructive trees, shrub cover, herb cover, CI, hemeroby, organic matter content, available P available K, capacity exchange. These indexes were used to establish evaluation index system and rational mathematical model had good performance. The assessment results and the actual meted. According to the values of natural closeness comprehensive index, the order and the value of different communities were : Tsuga chinensis community (0.97)> Pinus armandii and Tsuga chinensis community (0.89)> Pinus armandii and Cephalotaxus sinensis community (0.75)> Betula albo-sinensis community (0.50)> Pinus armandii (0.38)> Pinus armandii and Cephalotaxus sinensis community (0.14)> Larix gmellini community (0.02).8 In Huoditang Experiment and Demonstration Site, near natural forest area ratio was 19.9%, semi-natural forests ratio was 14.9%, sub-natural forest area ratio was 11.6%, near plantation area ratio was 19.9%, exotic species artificial plantation area ratio was 33.7%. The natural closeness of Tsuga chinensis stand was the highest and all the stands were in the close to natural state; In Pinus armandii stands, near natural forest area ratio was 24.4%, semi-natural forest area ratio was 32.3%, near plantation area ratio was 43.3%. All the Betula albo-sinensis stands were in sub-natural state and staged in pioneer community at present. Larix gmellini community was plantation of exotic species, whose natural closeness was the lowest.9. The biotope map that mapped through GIS technology could clearly determine the various degrees of natural closeness, which was facilitated and scientific forest management tool. Based on biotope map, the management measures were proposed: hillsides-closed and protection type, upbringing and protection type, replanting and hillsides-closed type, selective cutting and upbringing type, upbringing and reformation type, and transformation and thinning type. Management measures invetion biotope map was also mapped through GIS technology.