**Table 14 Statistical analysis for fluctuated concentration rate of trees structure type**

a. Group statistics |

Classification | Number of samples (N) | Mean (%) | Std. deviation | Std. error | Min (%) | Max (%) |

Trees 1 column | 80 | 84.774 | 23.8102 | 26621 | 35.6 | 132.0 |

Trees 2 column | 144 | 79.493 | 19.4614 | 1.6218 | 44.3 | 124.4 |

Trees 3 column | 32 | 75.022 | 16.0382 | 2.8352 | 45.1 | 100.0 |

Total/mean | 256 | 80.584 | 20.7211 | 1.2951 | 35.6 | 132.0 |

b. Levene's test for equality of variances |

Levene's statistics | df1. | df2 | Significance probability |

6.211 | 2 | 253 | 0.002 |

c. Analysis of variance (ANOVA) |

Classification | Sum of squares | df | Mean squares | F | positive probability |

Between groups | 2565.695 | 2 | 1,282.847 | 3.035 | 0.050 |

Within groups | 106,921.883 | 253 | 422.616 | – | – |

Total | 109,487.578 | 255 | – | – | – |