Comparative Studies On The Dynamic Development Of Plant Populations Between The Road Area And The Forest Zone In Xiaolong Mountains Of Gansu Province

Because of the influence of human engineering and production,the natural vegetation has been compressed,the growth law and the dynamic characteristics of the wild plants have changed greatly.This paper selects Pinus tabuliformis,Pinus armandii,Quercus aliena var.acuteserrata,Larix principis-rupprechtii,Ulmus macrocarpa and Acer maximowiczii of the Bao Tian Road Area and forest zone of Xiaolong Mountains.A total of 6 representative plant communities.Drawing and analyzing population age structure,static life table and survival function curve;at the same time,using the spectral analysis and time series forecasting model,the paper discusses the development of 6 populations and analyzes the next 5 years,the next 10 years and the next 20 years.The results are as follows:(1)With the population age structure and survival curve characteristics shows that:In the road area Pinus armandii,Quercus aliena var.acuteserrata and Ulmus macrocarpa 3 populations survival curve are similar to the Deevey-?,they age structure are declining;Larix principis-rupprechtii and Acer maximowiczii populations survival curve are similar to the Deevey-?,they age structure are stable;Pinus tabuliformis population survival curve is similar to the Deevey-?,the age structure is growth.In the forest zone Pinus tabuliformis,Pinus armandii,Quercus aliena var.acuteserrata and Ulmus macrocarpa 4 populations survival curve are similar to the Deevey-?,they age structure are stable;Acer maximowiczii population is similar to the Deevey-?,the age structure is growth,Larix principis-rupprechtii population survival curve is similar to the Deevey-?,the age structure is declining.On the whole,the vegetation of the road area are declining,but the vegetation in natural forest are stable and growth.(2)The mortality and disappearance rate curve: In the road area population mortality and disappearance rate of the peak in 2,3,5 and 7,8,9 age class appeared,in addition to Pinus tabuliformis population,the mortality and disappearance rate of the other 5 populations is the minimum in 1 age class.The 6 populations of forest zone,in addition to Larix principis-rupprechtii population,the mortality and disappearance rate of the other 5 populations is the maximum in 1 age class.Different populations in 3,4,5 and 7,8,9 age class are also showing a higher rate of mortality and disappearance rate;the mortality and disappearance rate curve of Larix principis-rupprechtii population is disfferent from the other populations,showed a monotonic increasing trend.(3)From the analysis of 4 survival functions: In the road area 6 populations survival function and the cumulative mortality rate curves intersect at point 0.5,at the front of the point the survival rate is greater than the cumulative mortality,and at the rear of the point the survival rate is less than the cumulative mortality rate.The 6 populations of forest zone,except for Larix principis-rupprechtii population,the survival curve and cumulative mortality curve of the other 5 populations are not intersect,and the survival function of the 5 populations are always less than the cumulative mortality function.With the death density function and hazard rate function shows that the road area populations in the early growth stage showed growth,but in the late show state of recession;the populations of the forest zone in the early growth stage the number of individuals decreased rapidly,but showed a steady growth of the state in the late.(4)The spectrum analysis showed that: the 6 populations in the road arae and forest zone are subject to fundamental wave impact,Quercus aliena var.acuteserrata,Larix principis-rupprechtii,Ulmus macrocarpa and Acer maximowiczii of road arae and Pinus tabuliformis,Pinus armandii,Quercus aliena var.acuteserrata,Larix principis-rupprechtii and Acer maximowiczii of forest zone have significant effects of fundamental wave,there are small fluctuations in the basic cycle.But the Pinus tabuliformis and Pinus armandii populations of road area and the Ulmus macrocarpa population of forest zone have significant effects of 1/2 basic cycle length.The fundamental wave of forest populations are greater than the populations of road arae,explain in the Xiaolong Mountains forest zone which environment is relatively stable,natural forest periodic fluctuations is influenced by the biological and ecological characteristics of the population itself.(5)Through the time series prediction shows that: the number of individual about 6 populations in road area will gradually reduce over time,forest drying,seed germination rate,seedling and sapling growth inhibition is the main reason,after 20 years,the Larix principis-rupprechtii population will take the lead in recession,the number of individual about other populations also reduce,forest vegetation of road area in the overall recession.But after 20 years,the Pinus tabuliformis,Pinus armandii,Quercus aliena var.acuteserrata and Acer maximowiczii of forest zone the number of individuals on the basis of the current will be a small increase,showing steady growth state.