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Journal of Desert Research ›› 2022, Vol. 42 ›› Issue (4): 139-150.DOI: 10.7522/j.issn.1000-694X.2022.00001

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Canopy width prediction models for the Gurbantunggut Desert

Mingna Wang1(), Dinghai Zhang2(), Zhishan Zhang3, Lining Lu2   

  1. 1.School of Finance and Economics /, Gansu Agricultural University,Lanzhou 730070,China
    2.College of Science, Gansu Agricultural University,Lanzhou 730070,China
    3.Shapotou Desert Research and Experimental Station,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China
  • Received:2021-09-26 Revised:2022-01-13 Online:2022-07-20 Published:2022-08-29
  • Contact: Dinghai Zhang

Abstract:

The Gurbantunggut Desert, the main distribution area of fixed and semi-fixed dunes, is the second largest desert in China with a relatively large variety of sand-fixing shrubs. The canopy width is an essential parameter for the visualization of sand-fixing shrubs, which is also a necessary variable for the growth of desert vegetation. The purpose of this study was to assess the main sand-fixing shrubs on three types of sand dunes (fixed, semi-fixed, mobile dunes) in the sand zone. The experiment uses 12 base models, Backpropagation Neural Network (BP), Support Vector Machine (SVM) machine learning algorithms to develop a canopy width prediction model based on the height and crown length rate of sand-fixing shrubs. To compare the two machine learning algorithm fits,canopy prediction models suitable for the experiment was selected. The results were as follows: (1) The different optimal canopy width prediction models had a difference in dune types and shrub species, and the fixed and semi-fixed dune models outperform the mobile dune models. The three dune types were optimally fitted to the M2 (Quadratic Model) model. (2) The optimal models fitted for Haloxylon persicum on semi-fixed and mobile dunes were M2 and M7(Gompertz) model, respectively. The best-fitting model for Calligonum mongolicum was M2 model. In contrast, the better-fitting models for Serpentine and Artemisia ordosica were M2 and M7 model on semi-fixed and mobile dunes, respectively. Generally, the models of M2 and M7 had a better predictors of different types of shrub crown width values. (3) The Radial Basis Function (RBF) kernel-based support vector regression machine was better than the BP neural network model in crown width prediction.

Key words: plant height, crown width, crown length rate, base model, BP neural network, support vector machine

CLC Number: