| In order to solve the problem of introduction and degradation of camphor pine in sandy land in Inner Mongolia Autonomous Region,the forest characteristics and renewal status of the introduction site were investigated according to the geographical latitude,the germination experiments of seeds in different regions were conducted,the meteorological data of various regions were collected,and the main influencing factors regulating natural renewal were found out.Through the investigation of fruit,seed morphological characteristics,natural renewal status and environmental geographical factors,Arc GIS was used for renewal regionalization,SPSS one-way variance and correlation analysis,and the natural reproduction and renewal of P.sylvestrae in sandy land in Inner Mongolia Autonomous Region was studied.The main results are as follows:(1)There are cones in camphor pine trees in 10 areas and seeds in the cones.Significant difference(P <0.05),but no effect on the natural renewal of the seed number in different regions(P <0.05),the number of seeds from the northeast to southwest,20%-30% more than the seed rate in different regions(P <0.05),the seed rate increasing from the northeast to southwest,5-10 times that of the fruit.The poor quality of introduced earth fruits may be an important reason for the natural renewal of P.camphor.Seeds in all 10 areas can germinate and grow normally after germination.Seed germination rate and germination rate in different regions(P <0.05),the overall performance of high germination rate and germination rate,low germination rate in the central region,the eastern and western region was about 2 times that of the central region.The first germination time of seeds in different regions was on day 2.(2)There are natural renewal seedlings,and young trees in Alki,Arshan,Guzherstand and forest edge,which can complete natural renewal;Kulun,Zhanggutai,Wangdian,Manhan Mountain,Serene and forest edge are only existing seedlings,which can artificially promote natural renewal;Hohhot and Little Hololline and forest edge have no natural renewal.In the perspective of renewal suitability,four divisions are made: natural reproduction and renewal area,artificial promotion of natural reproduction and renewal area,introduction and growth with good but not renewal area,and introduction area with poor growth.(3)The average annual temperature and winter and spring temperature were significantly negatively associated with the renewal index.With average annual temperature below 2.5℃,2.55 and 2.5℃-7℃.Low temperature in spring and winter is the key to the natural reproduction and renewal of Pinus sylvestrus.January and December average precipitation and annual snow cover days were significantly and positively correlated with the renewal index.The sum of precipitation in January and December in the natural breeding and renewal areas is above 6mm,2-3 times that of other introduced areas.The annual snow days in natural reproduction area is above100 d,30-50 d,3-4 times;the introduction and growth is between 20-30 d,and the annual snow days in natural reproduction area is 4-8 times.Annual evaporation and winter and spring evaporation showed a significantly negative correlation with the renewal index.The annual evaporation of natural breeding renewal area is less than 1650 mm,300-500 mm less than other introduced areas,and the evaporation of spring and winter is less than 210 mm,more than 100 mm less than his introduced areas.The relative humidity of air and renewal index in winter and spring.In natural reproduction and renewal areas,the relative humidity in 1,2 and December is above 65,with relative humidity above 60 in November and relative humidity above 55 in March.Suitable forest density(500 plants / ha-800 plants / ha),herbaceous shrub cover(10%-70%)and elevation(700m-1500m)can significantly affect the natural renewal of sylvestrus forest.(4)Soil moisture content is in the range of 2%-20%,and the emergence rate of camphor pine seed increases with the increase of soil water content.With the increase of soil moisture content,the emergence time gradually decreases,and the emergence rate gradually increases.Temperature has no effect on the germination rate of camphor pine seeds.With the increase of temperature,the average germination time is shorter and the germination rate increases,but the probability of seed mildew increases,so it is more suitable for germination in low temperature environment. |
