Effces Of High-density Diplopterygium Glaucum On The Update And Growth Of Schima Superba Secondary Forest

There had little researches about the high-density "Diplopterygium glaucum layer" which formed on Tiantong Mountains, Zhejiang province in 1989, and had great effects on the growth community structure and succession of Secondary Schima superba forest. Therefore, it’s necessary to carry out the impact and influence factor of ferns on the forest ecological system structure and dynamic change in the process, for the purpose of providing theory support on future study, and giving scientific guidance to the operation and management of forest.The survey data of the Schima superba forest with high-density Diplopterygium glaucum in 1972,1983,2003 and 2014 form the forestry centre was adopted in this research, aimed to study the influence of high-density Diplopterygium glaucum to Schima superba forest. And in order to kowning more about it, this research setted 15 high-density Diplopterygium glaucum and 5 low-density Diplopterygium glaucum plots in 2014. It aslo had done someothers’ experiment, aimed to kowning the influence of high-density Diplopterygium glaucum on seed, sapling and the temperature and humidity of soil.The results are conclude below:1. After 42a’s succession of the Schima superba forest with high-density Diplopterygium glaucum, the species richness was maintained a stable overall, the species composition had been changed, Castanopsis fargesii and Castanopsis carlesii which is the dominant species of Subtropical Evergreen Broad-leaved Forest had been missed, while added Neolitsea aurata var. chekiangensis and Myrica rubra. By the time, Schima superba and Lithocarpus glaber which is the dominant population of the Schima superba forest with high-density Diplopterygium glaucum, lack of it’s sapling that DBH< 13 cm. Compared with the community survey data of the Schima superba forest with high-density and low-density Diplopterygium glaucum, we could kown that the growth of stand volume for broad-leaved tree species in the Schima superba forest with high-density Diplopterygium glaucum was 2.132 m3·hm -2·a-1, the proportion of big tree that DBH≥ 17 cm is more than the sapling. While in the Schima superba forest with low-density Diplopterygium glaucum, the growth of stand volume for broad-leaved tree species was 4.948 m3·hm -2·a-1, and had the same proportion between the sapling that DBH< 17 cm and big tree. These researches showed that the stand growth became slower, lack of saplings and seedlings and the community update was hindered in the Schima superba Secondary forest, with the influence of high-density Diplopterygium glaucum.2. By the further analysis and comparison of community survey data, which from the Schima superba forest with high-density and low-density Diplopterygium glaucum samples were setted in 2014,we can kown that:1) There was no significant difference on the species composition and species diversity index in the two kind of Schima superba forest; 2) The Schima superba forest with high-density Diplopterygium glaucum had lower of stand density of main layer, succession layer, aspling layer and seedlings, compared to the Schima superba forest with low-density Diplopterygium glaucum; And the per hectare density of seedling was 58515 plants in the Schima superba forest with low-density Diplopterygium glaucum, more than 55181 plants as to the Schima superba forest with high-density Diplopterygium glaucum;3) The structure of Schima superba and Castanopsis fargesii population was decline cype, which was dominant species of the Schima superba forest with high-density Diplopterygium glaucum, meanwhile the seedling, sapling had missed, and update was hindered. While structure of all the dominant species population which in the Schima superba forest with low-density Diplopterygium glaucum was developed type unless Schima superba;4) There had slower forest stand growth, moreover the dominant species(Lithocarpus glaber,Castanopsis fargesii and Castanopsis carlesii)of lower density, larger volume and lower loss rate in the Schima superba forest with high-density Diplopterygium glaucum, as it to the Schima superba forest with low-density Diplopterygium glaucum. Above all, we could kown that the balance of community structure was destroyed, and the dominant species was aslo withered and declined in the Schima superba forest with high-density Diplopterygium glaucum. As a result, the community renewal ability was weakened which would hidered the succession.3. The soil temperature and humidity had reduced, also the growth of Lithocarpus glaber sapling had been restrained with the influences of high-density Diplopterygium glaucum, while the germination rate of seed had risen.