Summary of the invention
The growth of China fir year carbon density is calculated using DEM terrain factor technical problem to be solved by the invention is to provide a kind of
The calculation method of amount provides a kind of convenient and fast method for the estimation of China fir organic C storage.
To achieve the above object, the technical solution of the present invention is as follows:
A kind of China fir carbon density calculation method based on DEM terrain factor, comprising the following steps:
(1) it extracts terrain factor and calculates weight
The research area gradient in extraction digital complex demodulation data, slope aspect, height above sea level, gradient variability, slope aspect variability respectively
As terrain factor, the weight of each terrain factor is calculated separately using rough set method, then calculates separately each age as follows
The synthesis terrain factor F of group:
F=W1X1+W2X2+W3X3+W4X4+W5X5
In formula, X1For slope aspect, X2For height above sea level, X3For the gradient, X4For gradient variability, X5For slope aspect variability, W1The weight of slope aspect,
W2The weight of height above sea level, W3The weight of the gradient, W4The weight of gradient variability, W5The weight of slope aspect variability;
(2) biomass and Live carbon storage are estimated
1. biomass estimation
China fir biomass, China fir biomass estimation equation are estimated using conversion factor continuous function method are as follows:
B=aV+b,
In formula: B is unit area biomass;V is unit area accumulation, and a and b are respectively parameter, take a=0.3999, b
=22.5410;
B is divided by the age of stand up to unit area China fir year biomass;
2. Carbon fixation and carbon density estimation
The mean carbon content of each organ of cohort lanceolata forest is not multiplied by the China fir biomass of corresponding age group up to not cohort
Chinese fir Stand Live carbon storage;
Carbon density is the Live carbon storage of each age group standing forest divided by corresponding standing forest area;
(3) the year carbon density model of different China fir age groups is established
According to the synthesis terrain factor of standing forest terrain factor and each age group obtained by step (1), with step (2) resulting correspondence
The carbon density data of standing forest obtain each age of stand group year carbon density using successive Regression or linear regression fit and estimate as observation
Model is as follows:
Young growth: Y=0.001F+2.04;
Middle-aged forest: Y=0.001F+2.05;
Near-mature forest: Y=11.24-0.064X4-0.088X3-0.171X5;
Mature forest: Y=-0.0025F+1.69;
Overmature forest: Y=0.01X2+0.828;
In the above formulas, Y is year carbon density, and F is comprehensive terrain factor, X2For height above sea level, X3For the gradient, X4For gradient variability,
X5For slope aspect variability.
In the terrain factor, slope aspect quantify as follows: Schattenseite quantized value is 1, and half Schattenseite quantized value is 2, half tailo
Quantized value is 3, and tailo quantized value is 4.
The criteria for classifying of the China fir age group are as follows: young growth≤10 year, middle-aged forest 10~20 years, near-mature forest 21~25 years,
Mature forest 26~35 years, overmature forest was 35 years or more.
The mean carbon content of each organ of the not cohort lanceolata forest are as follows: the mean carbon content of young growth is 0.47, middle age
The mean carbon content of woods is 0.48, and the mean carbon content of near-mature forest is 0.49, and the mean carbon content of mature forest is 0.54.
The present invention has the advantages that using the calculated China fir year carbon density of calculation method and actual measurement of the invention
For error within allowed band, R value reaches the level of signifiance between numerical value.The calculation method is just with the landform in dem data
The factor can estimate China fir carbon density increment, simple and convenient, provide a kind of method for organic C storage estimation in regional scope.
Specific embodiment
It elaborates with reference to embodiments to a specific embodiment of the invention, but does not constitute and right of the present invention is wanted
Ask the limitation of protection scope.
China fir carbon density calculation method based on DEM terrain factor of the invention, step include:
1. extracting terrain factor and calculating weight:
Extract the research area gradient in digital complex demodulation data, slope aspect, height above sea level, slope respectively using ArcGIS tool
Variability, slope aspect variability are spent as terrain factor.Because slope aspect is descriptive index, slope aspect is quantified in calculating process, Schattenseite
Quantized value is 1, and half Schattenseite quantized value is 2, and half tailo quantized value is 3, and tailo quantized value is 4.Terrain factor is extracted to provide with forest
For minimum statistics unit standing forest in the investigation statistics data of source as unit, the terrain factor extracted represents the ground of corresponding standing forest
Shape.Each landform Factor Weight of each age group is calculated separately using rough set method, the results are shown in Table 1.
Each age group terrain factor weight of table 1.
Each age group criteria for classifying are as follows: young growth≤10 year, middle-aged forest 10~20 years, near-mature forest 21~25 years, mature forest 26
~35 years, overmature forest was 35 years or more.
Calculate separately the synthesis terrain factor F of each age group as follows again:
F=W1X1+W2X2+W3X3+W4X4+W5X5。
In formula, X1For slope aspect, X2For height above sea level, X3For the gradient, X4For gradient variability, X5For slope aspect variability, W1For the power of slope aspect
Weight, W2For the weight of height above sea level, W3For the weight of the gradient, W4For the weight of gradient variability, W5For the weight of slope aspect variability.
2. the estimation of biomass and Live carbon storage:
Accumulation in research on utilization area forest land forest resource survey data estimates that China fir biomass in unit area, carbon store
Accumulated amount and carbon density, the specific steps are as follows:
1. biomass estimation
China fir biomass estimation uses conversion factor continuous function method, and the conversion factor continuous function method is referring to square essence
Cloud, Liu Guohua, the biomass and net production [J] of Xu Song age China forest cover, Acta Ecologica Sinica, 1996,16 (5): 497-
508.China fir biomass estimation equation are as follows: B=aV+b, in formula: B is unit area biomass (thm-2), V is unit area storage
Accumulated amount (m3·hm-2), a and b are respectively parameter.The relative growth that this expression formula meets biology is theoretical, has generality.Take a
=0.3999, b=22.5410.Estimate resulting China fir biomass B divided by the age of stand up to unit area China fir year biomass.
2. Carbon fixation and carbon density estimation
The carbon content of China fir difference age of stand section has different, therefore using the average carbon of not each organ of cohort lanceolata forest
Content is multiplied by its corresponding biomass estimation not cohort Chinese fir Stand Live carbon storage.
The wherein not mean carbon content of each organ of cohort lanceolata forest: young growth 0.47, middle-aged forest 0.48, near-mature forest
It is 0.49, mature forest 0.54.
Carbon density is the Live carbon storage of each age group standing forest divided by corresponding standing forest area.
3. establishing year carbon density appraising model:
Using the relationship between standing forest terrain data and year carbon density increment, according to step 1 gained standing forest terrain factor
With the synthesis terrain factor F of each age group, using the carbon density data of the resulting corresponding standing forest of step 2 as observation, using gradually
It is as shown in table 2 that recurrence or linear regression fit obtain each age of stand group year carbon density appraising model:
Each age of stand group year carbon density appraising model of table 2.
In table 2, R2It is the goodness of fit of model, is the bigger the better, n represents observation data volume.
The method of the present invention, it is only necessary to have the DEM terrain data of target area, using ArcGIS tool extract DEM landform because
Son can estimate the China fir carbon density value in the region according to above-mentioned model.
Example 1: father's concubine mountain Young Growth of Chinese Fir standing forest, the age of stand 5 years, area 2.58hm2
Utilize ArcGIS tool extract DEM terrain factor: slope aspect be half tailo (quantized value 3), 851.68 meters of height above sea level, slope
Degree 22.99, gradient variability sos value 6.76, slope aspect variability soa value 4.69 are counted according to young growth year carbon density appraising model
It calculates, which is 2.28tChm-2, then standing forest Live carbon storage is 29.41tC.
Example 2: forest farm Middle-aged China-fir standing forest in happy, the age of stand 11 years, area 5.42hm2
Utilize ArcGIS tool extract DEM terrain factor: slope aspect be Schattenseite (quantized value 1), 792.83 meters of height above sea level, the gradient
25.89, gradient variability sos39.55, slope aspect variability soa9.44 are calculated according to middle-aged forest year carbon density appraising model, should
Standing forest year carbon density is 2.27tChm-2, then standing forest Live carbon storage is 135.34tC.
3: Huang Mian forest farm China fir near-mature forest standing forest of example, the age of stand 25, area 1.86hm2
Utilize ArcGIS tool extract DEM terrain factor: slope aspect be Schattenseite (quantized value 1), 501.67 meters of height above sea level, the gradient
40.5, the gradient variability sos value 48.48, slope aspect variability soa value 12.37 are counted according to near-mature forest year carbon density appraising model
It calculates, which is 2.46tChm-2, then standing forest Live carbon storage is 114.30tC.
Example 4: refined long forest farm Cunninghamia lanceolata mature plantation standing forest, the age of stand 30, area 0.74hm2
Utilize ArcGIS tool extract DEM terrain factor: half Schattenseite of slope aspect (quantized value 2), 746.83 meters of height above sea level, the gradient
14.59, the gradient variability sos value 47.48, slope aspect variability soa value 7.29 are counted according to mature forest year carbon density appraising model
It calculates, which is 1.28tChm-2, then standing forest Live carbon storage is 28.42tC.