Fundamental Study On Restoration And Reconstruction Technique Of Typical Poplar Plantation In Zhangbei County,Bashang Area

This article is take the structure and function characteristics of the typical poplar plantation ecological system in Zhangbei County,Bashang Area as the object of study.According to the data of forest health survey in Zhangbei County,Bashang Area,the vegetation succession of typical poplar plantation studied with qualitative description and quantitative calculation;Also the data applied to analysis the structure characteristics that tree species composition,diameter and height distribution and the function characteristics that wind-speed reduction and sand-break,water conservation,improving soil fertilizer and biological diversity with qualitative description and quantitative calculation.The structure and function characteristics of typical poplar plantation be analysised with PCA(Principle Components Analysis),and the restoration and reconstruction technique were came up with the results of comprehensive evaluation on structure and function characteristics.The main conclusions are as follows:(1)Analysis on age class distribution of vegetation community,survey on seedling recruitment,calculated on rate of dying tree,and analysis on reason for degradation.The ecological function would be played steadily with Simon poplar and Simon poplar forest,but the Beijing poplar and Cathay poplar forest wouldn't be played steadily for aged,and the structure and function characteristics would be degradated.According to analyze diameter distribution law of typical poplar forest,there are three types which were truncated normal distribution,bimodal distribution and approximate normal distribution.Distribution of height of typical poplar forest was mainly single peak distribution,the multi-peak distribution is less.(2)The order that sediment reduction effective and wind reduction effective of typical poplar plantation land is same.There is greater difference among the function characteristics that wind-speed reduction and sand-break,water conservation,improving soil fertilizer and biological diversity,the order of wind reduction effective is Lombardy poplar(36.61±2.85%)>Cathay poplar(34.34±3.48%)>Simon poplar(28.69±1.54%)>Beijing poplar(20.14±0.62%).The order of sediment reduction is Beijing poplar(7.68±0.43kg)>Simon poplar(5.6±0.56kg)>Cathay poplar(3.3 5±0.14kg)>Lombardy poplar(3.25±0.23kg).The best of sediment reduction effective is Lombardy poplar,the least is Beijing poplar.(3)The order of interception amount of typical poplar forest is Cathay poplar(0.60±0.13mm)>Lombardy poplar(0.32±0.04mm)>Beijing poplar(0.28±0.01mm)>Simon poplar(0.08±0.01 mm).The order of average rate of water holdup of typical poplar is Lombardy poplar forest(44.53±7.48%)>Simon poplar forest(3 8.73±8.68%)>forest(23.84±3.34%)>Cathay poplar forest(2.68 ± 0.12%).The order of storage capacity of typical poplar is Lombardy poplar forest(1075.00±27.40t/hm2)>Simon poplar forest(788.54±111.28t/hm2)>Cathay poplar forest(800.13±82.73t/hm2)>Beijing poplar forest(791.35±37.30t/hm2).Compare with the canopy interception and the litter water-holding and soil water storage,the highest rate of contribution for total water conservation was soil water storage,and the soil water storage account for 84.87%.(4)All the pH values more than 7.5,the soil of typical poplar forest presented alkalescence.The order of nutrient content of the typical forest land is:TK>TN>TP,available K>alkali-nitrogen>available P.The order of organic matter content of the typical forest land is Lombardy poplar forest land(33.87±5.84g/kg)>Cathay poplar forest land(17.1 l±2.94g/kg)>Beijing poplar forest land(11.55±0.85g/kg)>Simon poplar forest land(10.21 ± 1.07g/kg).(5)The diversity of four typical poplar plantations land is low.The maximum of index of Shannon-Wiener diversity of typical poplar forest is Lombardy poplar forest land(0.74±0.02)and the minimum is Beijing poplar forest land(0.65±0.02).The maximum of index of Patrick richness of typical poplar forest is Lombardy poplar forest land(45.50±2.70),and the minimum is Beijing poplar forest land(35.50±4.97).The maximum of Pielou of typical poplar forest is Simon poplar forest land(0.42±0.01),and the minimum is forest land(0.35±0.01).(6)There were twenty three indicators chose to apply the PCA(Principle Component Analysis)being evaluated comprehensive structure and function characteristics.The results showed that the comprehensive function of Lombardy poplar forest land at top of list,however,the comprehensive function of Simon poplar forest land ranked at bottom.According to the results,the result of comprehensive structure and function characteristics was divided to four classes which no degradation,mild degradation,moderate degradation,serious degradation.(7)According to the comprehensive evaluated results,there were four kinds of pattern model for restoration and reconstruction.The pattern which poplar and Mongolian pine mixed forest,poplar and Caragana korshinskii mixed forest poplar and Siberian apricot mixed forest,poplar and Siberian elm mixed forest were designed for forest restoration,and the reconstruction pattern which Mongolian pine pure forest,Mongolian pine and Caragana korshinskii mixed forest,Siberian elm and Caragana korshinskii mixed forest,Siberian elm and Siberian apricot mixed forest were designed for forest reconstruction.