Evaluation On Forestry Suitability Of Land Resource In Fujian Based On GIS

This study is based on GIS and mathematical model. Firstly the objects of evaluation include forest land, meadow, orchard, tea garden, plowland with beyond 25 slop, uncultured grass land, sand lot and bare land, the unit of evaluation is 250m X 250m grid. Secondly , on the base of probing and building the spatial and attributive database of factors of suitability evaluation through models such as digital elevation, trend,thiessen, inverse distance weighted interpolation and t test, making use of factor, theory analysis and correlation model, it selects from thirty_seven factors which reflect properties such as climatesatmospheric environment, the physical and chemical character of soil and social economy, and establish the factor system of suitability evaluation of forest land ; finally, it evaluate the suitability of forest land in Fujian, main restricted factors and degree by means of fuzzy sum method, AHP model,adding-multiplication model,dynamic classification model, the result is following:1. Through thiessen polygon interpolation, inverse distance weighted interpolation of twelve power, inverse distance weighted interpolation of one power, thiessen polygen interpolation, inverse distance weighted interpolation of two power, it can respectively calculate the differences between true values and N0x, PM10, S02, TSP, pH of acid rain which are least, as follow: 0. 079, 0. 979,1. 276, 0. 512 and 0. 049, this shows that the precision of those models of interpolation is best, those model can apply to the precise calculation of spatial datum such as N0x, PM10, SO₂, TSP and pH of acid rain.2. The coefficients of correlation which reflect models between atmospheric factors and longitude ( λ ) .latitude ( φ) .elevation (A) are from 0.629 to 0.982, those all reach the most remarkable level, and the t values between true values and values of the hereinbefore atmospheric factors which calculate by combining the trend model of two power and inverse distance weighted interpolation of six power, four power, one power, four power, two power, two power, one power, one power, three power, twelve power, one power, one power, four power, three power, the results show that using models of interpolation upward it can get the datum of atmospheric factors which have the best precision and apply to the precise calculation of spatial datum such as dryness degree. yearly raining day, the yearly hour of sunlight of the season of growth, yearly average rainfall, yearly percent of sunlight, accumulative temperature beyond zero degree, the yearly hour of sunlight, accumulative temperature beyond ten degree, yearly non-frost day, yearly average temperature, yearly radiant energy of sun, the ratio of precipitation between the season of growth and overwintering season, yearly frostday and the quantity of yearly evaporation.3.Nineteen fracors including slope, aspect,the thickness of soil,modulus of corrasion,quantity of salt,the organic substance,pH of soil,the whole phosphorus,the whole kalium, sticky grain of physics, pH of yearly acid rainfall, TSP,location of region, the value of traffic understand, accumulative temperature beyond ten degree, yearly non-frost day, the yearly hour of sunlight and yearly rainfall can be the dominant factors of evaluation on forestry suitability of land resource in Fujian.4. The result is following : The total area of land resource of forestry suitability in Fujian is 9,444,900 hektare, which respectively account for 78.01 percent of the area of land of whole province and 99.43 percent of the area of researching land, this shows that land resource of forestry suitability in Fujian is relatively abundant, it mainly distribute three regions such as Nanping, SanMing and Rongyan, which account for 61. 01 percent of land resource of forestry suitability of whole province. The area of preparatory land resource of forestry suitability of whole province is 574,100 hektare, which account for 6.08 percent of forestry suitability of land resource of whole province, this show that there are still a number of land resource of forestry suitability not to exploit, uncultured grass land is dominant in preparatory land resource of forestry suitability, whose area is 526,900 hektare and account for 91. 77 percent of preparatory land resource of forestry suitability of whole province. The quality of land resource of forestry suitability and preparatory land resource of forestry suitability is high, the area of high suitability respectively account for 64. 92 and 62. 98 of land resource of forestry suitability and preparatory land resource of forestry suitability. The main restrictions of land resource of forestry suitability of whole province are acidity, lack of phosphorus, viscidity and acid rain, which respectively account for 42. 09 percent, 30. 59 percent, 21. 75 percent and 14. 38 percent of land resource of forestry suitability of whole province, secondly, are lack of kalium,quantity of heat, corrasion, thinness and superficiality which respectively account for 7. 49 percent, 4. 83 percent , 4. 82 percent, 3. 75 percent and 3. 43 percent of land resource of forestry suitability of whole province, 43. 12 percent of land resource of high forest suitability has restricted factors of differect degree, which gives priority to low restriction and is mostly the restriction of cidity,lack of phosphorus, viscidity and acid rain, 80.30 percent of land resource of middle forest suitability has restricted factors of differect degree, which gives priority to low and middle restriction and is mostly the restriction of cidity,lack of phosphorus, viscidity , lacking of kalium and acid rain, all land resource of low forest suitability has restricted factors of differect degree,which gives priority to high restriction and is mostly the restriction of cidity, lack of phosphorus, viscidity, flimsiness and lacking of kalium.it brings out the corresponding countermeasures of reasonable utilization of land resource of forestry suitability based on the main problems of utilization of land...