| Site classification and site quality evaluation are the keys to scientific afforestation and forest management.Timber resources can no longer meet the needs of people's daily lives in China,and there is an urgent need to develop building timber forest cultivation technologies.Pinus tabulaeformis is an important forest resource in Hebei province.It is of great significance to divide the site types and evaluate site quality.It can provide guidance for the cultivation.In this study,the Pinus tabulaeformis forest was taken as the research object in Hebei province,92standard plots were laid out,combined with 191508 pieces of Hebei Pinus tabulaeformis second-class inventory plot data,the site classification and site quality evaluation study of Pinus tabulaeformis building materials were carried out.The main findings are as follows:(1)Statistical analysis of the overall distribution of Pinus tabulaeformis plantations in Hebei province.The total area of Pinus tabulaeformis plantations in Hebei reached 503922hm~2,and a total accumulation of 23488855m3.Accumulation of Pinus tabulaeformis plantations in Chengde were the largest,reaching264366 hm~2 and 14833714m3,accounting for 52.5%and 58.3%of the total.According to the analysis of all age groups,it was found that the Pinus tabulaeformis plantations in Hebei were mainly near-mature forests,accounting for 35.2%of the area,followed by middle-aged forests,accounting for 32.3%,and younger forests accounting for 13.1%.Based on Arc GIS software,the distribution map of Pinus tabulaeformis plantation resources in Hebei area and the distribution chart of the age group of Pinus tabulaeformis plantation were drawn.The distribution of Pinus tabulaeformis and age group can be presented more intuitively.(2)The dominant factors were selected from seven site factors by quantitative theory I(elevation,aspect,slope,soil thickness,soil type,humus thickness,litter thickness),and the dominant factor of Hebei Pinus tabulaeformis plantation is aspect and soil thickness,and the site types of Pinus tabulaeformis plantation forest were divided into six types:sunny slope with thin soil,sunny slope with medium soil,sunny slope with thick soil,shady slope with thin soil,shady slop with medium soil,shady slop with thick soil.Based on Arc GIS software,draw the distribution map of Pinus tabulaeformis plantation site type in Heibei.The Pinus tabulaeformis plantation forest in Hebei area is mainly distributed on the shady thin soil,with an area of 216182 hm~2,accounting for 42.9%of the total area,followed by the sunny slope thin soil,accounting for 27.42%,and the shaded and middle slope soil respectively compared with 17.81%and 10.55%.The thick soil on the sunny slope and the thick soil of shady slope account for less.(3)The site index table was prepared using the comparative advantage method.The chi-square test proved that the site index was qualified.The site index table was connected with the second-type survey data attribute table of Pinus tabulaeformis.Use Arc GIS software to draw the site index distribution map of Hebei Pinus tabulaeformis plantation.The site index of 7 has the largest area,accounting for 22.4.%of the total area,the site index of 8,accounting for 20.6%,and the site index of 4,accounting for only4.8%.This shows that the overall site quality of Pinus tabulaeformis plantations in Hebei is better.Suitable for nurturing building materials.(4)Selection of Pinus tabulaeformis wood with different site quality grades was carried out for physical and mechanical properties analysis.The analysis found that:wood physical and mechanical properties reached the medium or above level when the site quality are good and medium,meeting the requirements of building materials.Forest land with poor site quality is not suitable for cultivation of building materials.According to this,the map of suitable cultivation areas of Hebei Pinus tabulaeformis construction timber forest was drawn.(5)According to the distribution map of Hebei Pinus tabulaeformis plantation resources,the distribution map of Hebei Pinus tabulaeformis plantation site types,the distribution map of Hebei Pinus tabulaeformis plantation site index,and the map of the suitable area of Hebei Pinus tabulaeformis plantation forest site,it can be known that the total amount is rich,and the overall site quality is medium to high,suitable for cultivating Pinus tabulaeformis construction material forest.Hebei Chengde City is the best place to cultivate Pinus tabulaeformis construction material forest,followed by Qinhuangdao City,Baoding City,Tangshan City... |
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