Characteristics Of Natural Regeneration Of Sabina Vulgaris Community In Mu Us Sandland

Five sites was chosen from natural Sabina vulgaris community in experimental zone of exploitation and research center of Mu us sandland,WuShen banner, Erdos city.These were named respectively Salix cheilophila shrubs(A), Salix cheilophila + Sabina vulgaris(B), Sabina vulgaris + Salix cheilophila (C), Sabina vulgaris shrubs(D) and cutted Salix cheilophila plot(E). Sexual regeneration process of Sabina vulgaris community,including seed yield,seed bank,seedling dynamics and micro-habitat were studied using field experiments.The results are as following: Abundant cone was observed beneath Sabina vulgaris community in Mu us sandland, we concluded that seed yield could reach about 9118.5 per square meter. The difference of soil seed bank was so obvious in five site types, and seed quality was very poor. The seed density in top layer(0～5 cm) was higher than that in under layer(5～10 cm). Site A was of the largest seedling density ,was 17.4 seedling per square meter,accounts 30 percent of fine seeds in the surface soil. Site D had lost the ability to renovate. Few regenerate seedlings existed under Sabina vulgaris community, and seed regeneration came forth mainly in few mic-habitat, such as bottomland. Small seed bank, poor seed quality and comedown of regenerate entironment were primary factors limiting regeneration and development of natural Sabina vulgaris community. The trendline of annual average seedlings height and crown width was ascendling in site A. The increased rate was higher than death rate, that showing regenerate condition was well. The death rate of seedlings declined gradually with increasing of seedlings height. The growth speed of seedlings that height over 20cm reached 9.43cm/year,which was the most quick compared with that of other height levels. Direct ratio was revealed in growth speed and seedlings height. At the same time, linear correlative analysis was conducted on selecting meteorologic elements that might influence natural regeneration. Result showing,air temperature and precipitation being linear correlative relation with seedling growth index. Not symmetrical spatial pattern presenting that Sabina vulgaris seedlings was distributed mainly under the close Salix cheilophila canopies,and the number of Sabina vulgaris seedlings was more near truncal base. 50 plant species existed under the ground with Salix cheilophila shrubs,and including some hygrophytia plant. The ground with Salix cheilophila shrubs was of more high humidity, low temperature,shadycharacteristics. It was the most feasible microenvironment of regenerate Sabina vulgaris.